Quantum Supremacy by Dr Michio Kaku
Juan Carlos Zambrano
Gerente de Finanzas @ Tecnofarma Bolivia | Coaching ontologico
Quantum Supremacy by Dr Michio Kaku
Chapter 1 END OF THE AGE OF SILICON
A revolution is coming.
In 2019 and 2020, two bombshells rocked the world of science. Two groups announced that they had achieved quantum supremacy, the fabled point at which a radically new type of computer, called a quantum computer, could decisively outperform an ordinary digital supercomputer on specific tasks. This heralded an upheaval that can change the entire computing landscape and overturn every aspect of our daily life
First, Google revealed that their Sycamore quantum computer could solve a mathematical problem in 200 seconds that would take 10,000 years on the world’s fastest supercomputer. According to MIT’s Technology Review, Google called this a major breakthrough. They likened it to the launch of Sputnik or the Wright brothers’ first flight. It was the threshold of a new era of machines that would make today’s mightiest computer look like an abacus.
Quantum computers have been called the Ultimate Computer, a decisive leap in technology with profound implications for the entire world. Instead of computing on tiny transistors, they compute on the tiniest possible object, the atoms themselves, and hence can easily surpass the power of our greatest supercomputer. Quantum computers might usher in an entirely new age for the economy, society, and our way of life
But quantum computers are more than just another powerful computer. They are a new type of computer that can tackle problems that digital computers can never solve, even with an infinite amount of time. For example, digital computers can never accurately calculate how atoms combine to create crucial chemical reactions, especially those that make life possible. Digital computers can only compute on digital tape, consisting of a series of 0s and 1s, which are too crude to describe the delicate waves of electrons dancing deep inside a molecule. For example, when tediously computing the paths taken by a mouse in a maze, a digital computer has to painfully analyze each possible path, one after the other. A quantum computer, however, simultaneously analyzes all possible paths at the same time, with lightning speed
Given the profound implications of this revolution, it is not surprising that many of the world’s leading corporations have invested heavily in this new technology. Google, Microsoft, Intel, IBM, Rigetti, and Honeywell are all building quantum computer prototypes. The leaders of Silicon Valley realize that they must keep pace with this revolution or be left in the dust
Many scientists believe that we are now entering an entirely new era, with shock waves comparable to those created by the introduction of the transistor and the microchip. Companies without direct ties to computer production, like the automotive giant Daimler, which owns Mercedes-Benz, are already investing in this new technology, sensing that quantum computers may pave the way for new developments in their own industries. Julius Marcea, an executive with rival BMW, has written, We are excited to investigate the transformative potential of quantum computing on the automotive industry and are committed to extending the limits of engineering performance. Other large companies, like Volkswagen and Airbus, have set up quantum computing divisions of their own to explore how this may revolutionize their business.
Quantum Supremacy
Back in 2012, when physicist John Preskill of the California Institute of Technology first coined the term quantum supremacy, many scientists shook their heads. It would take decades, if not centuries, they thought, before quantum computers could outperform a digital computer. After all, computing on individual atoms, rather than wafers of silicon chips, was considered fiendishly difficult
Quantum computer. But these stunning announcements of quantum supremacy have so far shredded naysayers’ gloomy predictions. Now the concern is shifting to how fast the field is developing
End of Moore’s Law
What is driving all this turmoil and controversy?
The rise of quantum computers is a sign that the Age of Silicon is gradually coming to a close. For the past half-century, the explosion of computer power has been described by Moore’s law, named after Intel founder Gordon Moore. Moore’s law states that computer power doubles every eighteen months. This deceptively simple law has tracked the remarkable exponential increase in computer power, which is unprecedented in human history. There is no other invention which has had such a pervasive impact in such a brief period of time.
As Intel’s Sanjay Natarajan has said, We’ve squeezed, we believe, everything you can squeeze out of that architecture.
Silicon Valley may eventually become the next Rust Belt
Although things seem calm now, sooner or later this new future will dawn. As Hartmut Neven, director of Google’s AI lab, says, It looks like nothing is happening, nothing is happening, and then whoops, suddenly you’re in a different world.
Why Are They So Powerful?
What makes quantum computers so powerful that the nations of the world are rushing to master this new technology?
Essentially, all modern computers are based on digital information, which can be encoded in a series of 0s and 1s. The smallest unit of information, a single digit, is called a bit. This sequence of 0s and 1s is fed into a digital processor, which performs the calculation, and then produces an output
However, Nobel laureate Richard Feynman in 1959 saw a different approach to digital information. In a prophetic, pathbreaking essay titled There’s Plenty of Room at the Bottom and subsequent articles, he asked: Why not replace this sequence of 0s and 1s with states of atoms, making an atomic computer? Why not replace transistors with the smallest possible object, the atom?
Atoms are like spinning tops. In a magnetic field, they can align either up or down with respect to the magnetic field, which can correspond to a 0 or a 1. The power of a digital computer is related to the number of states (the 0s or 1s) you have in your computer.
But due to the weird rules of the subatomic world, atoms can also spin in any combination of the two. For example, you can have a state in which the atom spins up 10 percent of the time and spins down 90 percent of the time. Or it spins up 65 percent of the time and spins down 35 percent of the time. In fact, there are an infinite number of ways that you can have an atom spin. This vastly increases the number of states that are possible. So the atom can carry much more information, not just in a bit, but a qubit, i.e., a simultaneous mixture of the up and down states. Digital bits can only carry one bit of information at a time, which limits their power, but qubits, or quantum bits, have almost unlimited power. The fact that, at the atomic level, objects can exist simultaneously in multiple states is called superposition. (This also means the familiar laws of common sense are routinely violated at the atomic level. At that scale, electrons can be in two places at the same time, which is not true for large objects.)
In addition, these qubits can interact with each other, which is not possible for ordinary bits. This is called entanglement. Whereas digital bits have independent states, each time you add another qubit, it interacts with all the previous qubits, so you double the number of possible interactions. Hence, quantum computers are inherently exponentially more powerful than digital computers, because you double the number of interactions every time you add an additional qubit
Google’s Sycamore quantum computer, which was the first to achieve quantum supremacy, has the power to process 72 billion billion bytes of memory with its fifty-three qubits. So a quantum computer like Sycamore dwarfs any conventional computer
The commercial and scientific implications of this are enormous. As we transition from a digital world economy to a quantum economy, the stakes are extraordinarily high
Speed Bumps to Quantum Computers
The problem facing quantum computers was also foreseen by Richard Feynman when he first proposed the concept. In order for quantum computers to work, atoms have to be arranged precisely so that they vibrate in unison. This is called coherence. But atoms are incredibly small and sensitive objects. The smallest impurity or disturbance from the outside world can cause this array of atoms to fall out of coherence, ruining the entire calculation. This fragility is the main problem facing quantum computers. So the trillion-dollar question is: Can we control decoherence?
In order to minimize the contamination coming from the outside world, scientists use special equipment to drop the temperature to near absolute zero, where unwanted vibrations are at a minimum. But this requires expensive, special pumps and tubing to reach those temperatures
But we are faced with a mystery. Mother Nature uses quantum mechanics at room temperature without a problem. For example, the miracle of photosynthesis, one of the most important processes on earth, is a quantum process, yet it takes place at normal temperatures. Mother Nature does not use a roomful of exotic devices operating at near absolute zero to execute photosynthesis. For reasons that are not well understood, in the natural world coherence can be maintained even on a warm, sunny day, when disturbances from the outside world should create chaos at the atomic level. If we could one day figure out how Mother Nature performs her magic at room temperature, then we might become masters of the quantum and even life itself
Revolutionizing the Economy
Although quantum computers pose a threat to the cybersecurity of nations in the short term, they also have vast practical implications in the long term, with the power to revolutionize the world economy, create a more sustainable future, and usher in an era of quantum medicine to help cure previously incurable diseases
There are many areas where quantum computers can overtake conventional digital computers:
Now, increasingly it is measured in data. Companies used to throw their own financial data away, but now this information is being recognized as more valuable than precious metals. But sifting through mountains of data may overwhelm a conventional digital computer. This is where quantum computers come in, by finding the needle in the haystack. Quantum computers may be able to analyze a company’s finances in order to isolate the handful of factors that are preventing it from growing
Once quantum computers have used search engines to identify the key factors in the data, the next question is how to adjust them to maximize certain factors, such as profit. At the very least, large corporations, universities, and government agencies will use quantum computers to minimize their expenses and maximize their efficiency and profit
Quantum computers might also solve complex equations that are beyond the ability of digital computers. For example, engineering firms may use quantum computers to calculate the aerodynamics of jets, airplanes, and cars, to find the ideal shape that reduces friction, minimizes cost, and maximizes efficiency
But perhaps the greatest benefit is to use quantum computers to simulate hundreds of vital chemical processes. The dream would be to predict the outcome of any chemical reaction at the atomic level without using chemicals at all, only quantum computers
Artificial intelligence (AI) excels at being able to learn from mistakes, so that it can perform increasingly difficult tasks. It has already proven its worth in industry and medicine. However, one limitation of AI is that the vast amount of data that it must process can easily overwhelm a conventional digital computer. But the ability to sift through mountains of data is one of the strong points of quantum computers. So the cross-fertilization of AI and quantum computers can significantly increase their power to solve problems of all kinds
Further Applications of Quantum Computers
Quantum computers have the power to change entire industries. For example, quantum computers may finally usher in the long-awaited Solar Age
Every new technology has to confront the bottom line: costs. After decades of singing the praises of solar and wind power, boosters have to face the fact that it is still a bit more expensive than fossil fuels on average. The reason is clear. When the sun does not shine and the winds don’t blow, renewable energy technology sits there unused, gathering dust.
The key bottleneck for the Solar Age is often overlooked; it is the battery. We have been spoiled by the fact that computer power grows exponentially fast, and we unconsciously assume that the same pace of improvement applies for all electronic technology
Computer power has exploded in part because we can use shorter wavelengths of ultraviolet radiation to etch tiny transistors on a silicon chip. But batteries are different; they are messy, using a collection of exotic chemicals in complex interplay. Battery power grows slowly and tediously, by trial and error, not by systematically etching with shorter wavelengths of UV light. Furthermore, the energy stored in a battery is a tiny fraction of the energy stored in gasoline.
Quantum computers could change that. They may be able to model thousands of possible chemical reactions without having to perform them in the laboratory in order to find the most efficient process for a super battery, thereby ushering in the Solar Age
Already, utilities and car companies are using first-generation quantum computers from IBM to attack the battery problem. They are trying to increase the capacity and recharging speed for the next generation of lithium-sulfur batteries
Feeding the Planet
Another crucial application of quantum computers might be to feed the world’s growing population. Certain bacteria can effortlessly take nitrogen from the air and convert it into ammonia, which is then turned into chemicals that become fertilizer. This nitrogen-fixing process is the reason why life flourishes on earth, allowing for the growth of lush vegetation that feeds humans and animals. The Green Revolution was unleashed when chemists duplicated this feat with the Haber-Bosch process. However, this process requires a vast amount of energy. In fact, an astounding 2 percent of the entire energy production of the world goes into this process
So that is the irony. Bacteria can do something for free that consumes a huge fraction of the world’s energy
The question is: Can quantum computers solve this problem of efficient fertilizer production, creating a second Green Revolution? Without another revolution in food production, some futurists have predicted an ecological catastrophe as an ever-expanding world population becomes more and more difficult to feed, which could lead to mass starvation and food riots around the globe
Already, scientists at Microsoft have made some of the first attempts to use quantum computers to increase the yields from fertilizers and unlock the secret of nitrogen fixing
Scientists have spent decades trying to tease apart all the steps behind this process, molecule for molecule. But the problem of converting light into sugar is a quantum mechanical process. After years of effort, scientists have isolated where quantum effects dominate this process, and all are beyond the reach of digital computers. Therefore, to create a synthetic photosynthesis that could potentially be more efficient than the natural one still eludes our finest chemists.
Quantum computers may be able to help create a more efficient synthetic photosynthesis or perhaps entirely new ways of capturing the power of sunlight. The future of our food supply may depend on this
Birth of Quantum Medicine
So quantum computers have the power to rejuvenate the environment and plant life. But they can also heal the sick and dying. Not only can quantum computers simultaneously analyze the efficacy of millions of potential drugs faster than any conventional computer, they can also unravel the nature of disease itself
Quantum computers may answer questions like: What causes healthy cells to suddenly become cancerous, and how can they be stopped? What causes Alzheimer’s disease? Why are Parkinson’s and ALS incurable? More recently, the coronavirus has been known to mutate, but how dangerous are each of these mutant viruses and how will they respond to treatment?
Two of the greatest discoveries in all of medicine are antibiotics and vaccines. But new antibiotics are found largely by trial and error, without understanding precisely how they work at the molecular level, and vaccines only stimulate the human body to produce chemicals to attack an invading virus. In both cases, the precise molecular mechanisms are still a mystery, and quantum computers may offer insight into how we might develop better vaccines and antibiotics
When it comes to understanding the body, the first giant step was the Human Genome Project, which listed all of the 3 billion base pairs and 20,000 genes that form a blueprint for the human body. But this is just the beginning. The problem is that digital computers are used mainly to search through vast databases of known genetic codes, but they are helpless when it comes to explaining precisely how DNA and proteins perform their miracles inside the body. Proteins are complex objects, often consisting of thousands of atoms, which fold up into a small ball in specific and unexplainable ways when they do their molecular magic. At its most fundamental level, all life is quantum mechanical, and so beyond the reach of digital computers
But quantum computers will lead the way into the next stage, when we decipher the mechanisms at the molecular level that tell us how they work, allowing scientists to create new genetic pathways, new therapies, new cures to conquer previously incurable diseases.
In addition, the aforementioned merger of AI and quantum computers may turn out to be the future of medicine. Already, AI programs like AlphaFold have been able to map the detailed atomic structure of an astounding 350,000 different types of proteins, including the complete set of proteins that make up the human body. The next step is to use the unique methods of quantum computers to find out how these proteins do their magic, and to use them to create the next generation of drugs and therapies.
Quantum computers are already being connected to neural networks, to create the next generation of learning machines that can literally reinvent themselves. The laptop sitting on your desk, by contrast, never learns. It is no more powerful today than it was last year. Only recently, with new advances in deep learning, are computers taking the first steps to recognizing mistakes and learning. Quantum computers could exponentially accelerate this process and have singular impacts on medicine and biology
Google CEO Sundar Pichai compares the arrival of quantum computers to the Wright brothers’ historic 1903 flight. The original test was not so amazing by itself, because the flight lasted only a modest twelve seconds. But this short flight was the trigger that initiated modern aviation, which in turn has changed the course of human civilization.
What is at stake is nothing less than our future. It’s up for grabs for whoever is able to build and use a quantum computer. But to truly understand the impact this revolution might have on our daily lives, it is useful to retrace some of the valiant attempts made in the past to fulfill our dream of using computers to simulate and understand the world around us.
And it all began with a mysterious, 2,000-year-old relic found at the bottom of the Mediterranean
Chapter 2 END OF THE DIGITAL AGE
From the bottom of the Aegean Sea came one of the most intriguing, captivating puzzles of the ancient world. In 1901, divers were able to salvage a strange curiosity near the island of Antikythera. Among the scattered pieces of broken pottery, coins, jewelry, and statues in a shipwreck, divers found one object that was oddly different. At first, it looked like a worthless piece of coral-encrusted rock.
But when layers of debris were cleaned off, archaeologists began to realize that they were staring at an exceedingly rare, one-of-a-kind treasure. It was full of gears, wheels, and strange inscriptions, a machine of intricate and exquisite design.
Nowhere in the ancient record was there any mention of a mechanism this sophisticated. It dawned on them that this magnificent machine must have been the pinnacle of scientific knowledge of the ancient world. It was a supernova of brilliance staring at them from millennia past. This was the world’s oldest computer, a device that would not be duplicated for another two thousand years.
So the purpose of the world’s first computer was to simulate heavenly bodies, to reproduce the mysteries of the cosmos in a device you could hold in your hands. Instead of just staring in awe at the night sky, these ancient scientists wanted to understand its detailed workings, allowing them unprecedented insight into the motion of celestial bodies in the heavens.
Quantum Computers: The Ultimate Simulation
Archaeologists found that the Antikythera represented the pinnacle of our ancient attempts to simulate the cosmos
Simulation is one of our deepest human desires. Children use simulation with toy figures to understand human behavior. When children play cops and robbers, teacher and student, or doctor and patient, they are simulating a piece of adult society in order to understand complex human relations
Sadly, it would take many centuries before scientists could build machines of sufficient complexity to simulate our world as well as the Antikythera could
Babbage and the Difference Machine
Charles Babbage, who is often called the Father of the Computer. He dabbled in a number of disparate fields, including art and even politics, but was always fascinated by numbers. Fortunately, he was born into a wealthy family, so his banker father could help him pursue many of his diverse interests.
His dream was to create the most advanced computing machine of his time, which could be used by bankers, engineers, sailors, and the military to unerringly perform tedious but essential calculations
He was quite persuasive in recruiting eager followers to help him advance his ambitious project. One of them was Lady Ada Lovelace, a member of the aristocracy and daughter of Lord Byron. She was also a serious student of mathematics, which was rare for women of that time. When she saw a small working model of Babbage’s project, she became intrigued by this exciting program
Lovelace is known for helping Babbage introduce several new concepts in computing. Usually, a mechanical computer required a set of gears and cogs to slowly and painstakingly calculate numbers, one by one
Lovelace was, in a sense, the world’s first programmer. Historians agree that Babbage was probably aware of the importance of software and programming, but her detailed notes written up in 1843 represented the first published account of a computer program.
But about a century after his death, engineers at the London Science Museum, by following his designs on paper, were able to finish one of his models and put it on display. And it worked, just as Babbage had predicted in the previous century.
Is Mathematics Complete?
In 1900, the great German mathematician David Hilbert listed the most important unproven mathematical questions of the time, challenging the world’s greatest mathematicians. This remarkable set of unsolved questions would then guide the agenda of mathematics for the next century as, one by one, each unproven theorem would be proven. Over the decades, young mathematicians would find fame and glory as they conquered one of Hilbert’s unfinished theorems
Alan Turing: Computer Science Pioneer
A few years later, one young English mathematician, who was intrigued by G?del’s famous incompleteness theorem, found an ingenious way to reframe the entire question. It
would forever change the direction of computer science.
Alan Turing’s exceptional ability was recognized early in his life. The headmistress of his elementary school would write that, among her students, she has clever boys and hardworking boys, but Alan is a genius. He would later be known as the father of computer science and artificial intelligence
Instead of building increasingly complex adding machines like Babbage’s difference engine, Alan Turing eventually asked himself a different question: Is there a mathematical limit to what a mechanical computer can perform?
Turing imagined an infinitely long tape, which contained a series of squares or cells. Inside each square, you could put a 0 or a 1, or you could leave it blank
Then a processor read the tape, and was allowed to make just six simple operations on it. Basically, you could replace a 0 with a 1, or vice versa, and move the processor one square to the left or right:
You can read the number in the square, You can write a number in the square, You can move one square to the left, You can move one square to the right, You can change the number in the square, You can stop
The Turing machine is written in binary language, rather than base 10. In binary language, the number one is represented by 1, the number two is represented by 10, the number three is represented by 11, the number four by 100, and so on. There is also a memory where numbers can be stored.) Then the final numerical result emerges from the processor as output.
In other words, the Turing machine can take one number and turn it into another according to precise commands in the software. So Turing reduced mathematics to a game: by systematically replacing 0 with 1 and vice versa, one could encode all of mathematics.
Computers in Warfare
Clearly, Turing had proved himself to be a mathematical genius of the highest caliber. But his research was interrupted by World War II. To aid in the war effort, Turing was recruited to perform top secret work at the British military installation at Bletchley Park outside London. There they were tasked with decoding secret Nazi codes
But Turing was also involved with another project, Colossus, with an even more ingenious design. Historians believe it was the world’s first programmable digital electronic computer. Instead of mechanical parts like the difference engine or the bombe, they used vacuum tubes, which can send electrical signals near the speed of light. Vacuum tubes can be compared to valves controlling the flow of water. By turning a small valve, one can shut off the water flowing in a much larger pipe, or let it flow unimpeded. This, in turn, can represent the number 0 or 1. So a system of water pipes and valves can represent a digital computer, where the water is like the flow of electricity. In the machines at Bletchley Park, a large array of vacuum tubes could perform digital calculations at enormous speeds by turning the flow of electricity on or off in the vacuum tubes. Thus, the work of Turing and others replaced the analog computer with a digital computer. One version of Colossus contained 2,400 vacuum tubes and filled up an entire room
Under the enormous pressure of wartime, Turing and his team were able to finally break the Nazi code around 1942, which helped defeat the Nazi naval fleet in the Atlantic. Soon, the Allies were able to penetrate the deepest secret plans of the Nazi military. The Allies were able to eavesdrop on Nazi instructions to their troops and anticipate their war plans. Colossus was finished in 1944, in time for the final invasion of Normandy, which the Nazis did not adequately prepare for. This sealed the fate of the Nazi empire.
Turing and the Creation of AI
After the war, Turing returned to an age-old problem that had intrigued him as a youth: artificial intelligence. In 1950, he opened his landmark paper on the subject by stating, I propose to consider the question: Can machines think?
Or to put it another way, is the brain a Turing machine of some sort?
He was tired of all the philosophical discussions that stretched back centuries about the meaning of consciousness, the soul, and what makes us human. Ultimately, all this discussion was pointless, he thought, because there was no definitive test or benchmark for consciousness.
So Turing came up with the celebrated Turing test. Put a human in a sealed room and a robot in another room. You are allowed to ask each one any written question and read their responses. The challenge is: Can you determine which room held the human? He called this test the imitation game.
The Turing test replaces endless philosophical debate with a simple reproducible test, to which there is a simple yes-or-no answer. Unlike a philosophical question, for which there is often no answer, this test is decidable
It is a tragedy that one of the creators of the computer revolution, who helped save the lives of millions and defeat fascism, was in some sense destroyed by his own country.
But another revolution in our understanding of the world would overturn this idea. Determinism would be overthrown. In the same way that G?del and Turing helped show that mathematics is incomplete, perhaps computers of the future would have to deal with the fundamental uncertainty introduced by physics.
So mathematicians would focus on a different question: Is it possible to build a quantum Turing machine?
Chapter 3 RISE OF THE QUANTUM
Max Planck, the creator of the quantum theory, was a man of many contradictions. On one hand, he was the ultimate conservative. It might be because his father was a professor of law at the University of Kiel, and his family had a long, distinguished tradition of integrity and public service. Both his grandfather and great-grandfather were theology professors, and one of his uncles was a judge.
He was cautious in his work, ever precise in his manners, and a pillar of the establishment. Judging by appearances, this mild-mannered man would be the last person you would think would become one of the greatest revolutionaries of all time, shattering all the cherished notions of previous centuries by opening up the quantum floodgates. But that is exactly what he did.
According to Newton, the universe was a clock. It was ticking away following his three laws of motion in a precise and predetermined way. This was called Newtonian determinism, which held sway for several centuries
But there was a nagging problem. There were a few loose strings, and by pulling on them, this elaborate Newtonian architecture would eventually unravel
Birth of the Quantum Theory
It was the first step in a long process that would eventually create the quantum computer.
Planck’s revolutionary insight meant that Newtonian mechanics was incomplete, and a new physics must emerge. Everything we thought we knew about the universe would have to be completely rewritten.
But being a proper conservative, he proposed his idea cautiously, diplomatically claiming that if you introduce this trick of packets of energy as an exercise, then you can precisely reproduce the actual energy curve found in nature.
To do the calculation, he had to introduce a number representing the size of the quantum of energy. He called it h (otherwise known as Planck’s constant, 6.62…x 10-34 joule-seconds), which is an incredibly small number. In our world, we never see quantum effects because h is so small. But if you could somehow vary h, one could continuously move from the quantum world to our everyday world. Almost like tuning a radio dial, one could turn it all the way down, so h = 0, and we have the commonsense world of Newton, where there are no quantum effects. But turn it the other way, and we have the bizarre subatomic world of the quantum, a world that, as physicists would shortly find out, resembled the Twilight Zone.
We can also apply this to a computer. If we let h go to zero, we arrive at the classical Turing machine. But if we let h get larger, then quantum effects begin to emerge, and we slowly turn the classical Turing machine into a quantum computer
Although his theory indisputably fit the experimental data and opened up an entirely new branch of physics, he was hounded for years by stubborn, die-hard believers in the classical, Newtonian idea. Describing this blizzard of opposition, Planck wrote: A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.
But no matter how fierce the opposition was, more and more evidence began to pile up confirming the quantum theory. It was indisputably correct
The man who explained the photoelectric effect was Albert Einstein, and he did it using Planck’s theory. Following Planck, Einstein claimed that light energy could occur in discrete packets or quanta of energy (later called photons) that could knock electrons out of a metal
One day, Austrian physicist Erwin Schr?dinger was discussing the idea of matter as a wave with a colleague. But if matter can act like a wave, his friend asked, then what is the equation that it must obey?
Schr?dinger was intrigued by that question. Physicists were familiar with waves, since they were useful in studying the optical properties of light, and were often analyzed in the form of ocean waves or sound waves in music. So Schr?dinger set out to find the wave equation for electrons. It was an equation that would completely overturn our understanding of the universe. In some sense, the entire universe, with all its chemical elements, including you and me, are solutions of Schr?dinger’s wave equation
Birth of the Wave Equation
Today, Schr?dinger’s wave equation is the bedrock of the quantum theory, taught in any graduate course in advanced physics. It forms the heart and soul of the quantum theory. I sometimes spend an entire semester at the City University of New York teaching the implications of this one equation
Schr?dinger’s equation was a bombshell. It was an immediate, overwhelming success. Previously, physicists like Ernest Rutherford thought that the atom was like a solar system, with tiny pointlike electrons circling around a nucleus. This picture, however, was much too simplistic because it said nothing about the structure of the atom and why there were so many elements
But if the electron was a wave, then the wave should form discrete resonances of definite frequencies as it circled around the nucleus. When one catalogued the resonances that an electron could make, one found a wave pattern that fit the description of the hydrogen atom perfectly.
How does this work? When we sing in the shower, only some of the waves from our voice can resonate between the walls, making a pleasing sound. We suddenly become great opera singers while in the shower. Other frequencies that don’t fit correctly inside the shower eventually die out and fade away. Similarly, if we beat on a drum, or blow on a trumpet, only certain frequencies are allowed to vibrate on its surface or in its pipes. This is the basis of music
The Quantum Atom
The periodic table of elements, which was painstakingly assembled by chemists over centuries, could now be explained using a simple equation, by solving for the resonances of electron waves as they whirl around the nucleus of the atom
It was breathtaking to realize that a single equation could explain the elements that make up the entire universe, including life itself. Suddenly, the universe was simpler than anyone thought
Chemistry has been reduced to physics
Waves of Probability
As spectacular and powerful as the Schr?dinger equation was, there was still one important, but embarrassing, question. If the electron was a wave, then what is waving?
The solution would divide the physics community right down the middle, pitting physicists against one another for decades to come. It would spark one of the most controversial debates in the entire history of science, challenging our very notion of existence. Even today, there are conferences debating all the mathematical nuances and philosophical implications of this split. And one by-product of this debate, as it would turn out, is the quantum computer
Physicist Max Born lit the fuse of this explosion by postulating that matter consists of particles, but the probability of finding that particle is given by a wave
This immediately cleaved the physics community in two, with the founders of the old guard on one side (including Planck, Einstein, de Broglie, and Schr?dinger, all denouncing this new interpretation), and Werner Heisenberg and Niels Bohr on the other, creating the Copenhagen school of quantum mechanics.
So with this new interpretation, the principles of quantum theory could now finally be expressed. Here is a (very simplified) summary of the basics of quantum mechanics:
But the most crucial and outrageous statement is number four, which holds that only after a measurement is made will the wave finally collapse and yield the correct answer, giving the probability of finding the electron in that state. One cannot know which state the electron is in until a measurement is made.
This is called the measurement problem
It is precisely postulates 3 and 4 that make quantum computers possible. The electron is now described as the simultaneous sum over different quantum states, which gives quantum computers their calculational power.
Ironically, Schr?dinger, whose equations started the whole quantum mechanics bandwagon in the first place, began to denounce this version of his own theory
Schr?dinger’s Cat
Schr?dinger’s cat is the most famous animal in all of physics. Schr?dinger believed it would demolish this heresy once and for all. Imagine, he wrote, there is a cat in a sealed box, which contains a vial of poison gas. This vial is connected to a hammer, which is attached to a Geiger counter next to a quantity of uranium. If an atom of the uranium decays, it activates the Geiger counter, which sets off the hammer, thus releasing the poison and killing the cat
Now here is the question that has baffled the world’s top physicists for the past century: Before you open the box, is the cat dead or alive?
A Newtonian would say that the answer is obvious: common sense says that the cat is either dead or alive, but not both. You can only be in one state at a time. Even before you opened the box, the cat’s fate was already predetermined.
However, Werner Heisenberg and Niels Bohr had a radically different interpretation.
They said that the cat is best represented by the sum of two waves: the wave of the live cat and the dead cat. When the box is still sealed, the cat can only exist as the superposition or sum of two waves simultaneously representing a dead and a live cat.
But is the cat dead or alive? As long as the box is sealed, this question makes no sense. In the microworld, things do not exist in definite states, but only as the sum of all possible states. Finally, when the box is opened and you observe the cat, the wave miraculously collapses and reveals the cat as being either dead or alive, but not both. So the process of measurement connects the microworld and the macroworld.
This has deep philosophical implications. Scientists spent many centuries arguing against something called solipsism, the idea that philosophers like George Berkeley believed that objects do not really exist unless you observe them
Microworld Versus Macroworld
But no matter how crazy the quantum theory appeared to be, its experimental success was indisputable. Many of its predictions (when predicting the properties of electrons and photons in what is called
For example, if we can hypothetically live in a completely quantum world, it means that everything we know about common sense is wrong. For example:
Entanglement
In 1930, Einstein had had enough. At the Sixth Solvay Conference in Brussels, Einstein decided he would go head-to-head and challenge Niels Bohr, the leading proponent of quantum mechanics. It was to be the Clash of Titans, with the greatest physicists of the age debating the very destiny of physics and the nature of reality. What was at stake was the very meaning of existence. Physicist Paul Ehrenfest would write, I will never forget the sight of the two opponents leaving the university club. Einstein, a majestic figure, walking calmly with a faint ironical smile, and Bohr trotting along by his side, extremely upset. Later, Bohr was so shaken that he could be seen muttering to himself, Einstein…Einstein…Einstein…
Physicist John Archibald Wheeler recalled, It was the greatest debate in intellectual history that I know about. In thirty years, I never heard of a debate between two greater men over a longer period of time on a deeper issue with deeper consequences for understanding this strange world of ours.
Five years later, Einstein mounted his final counterattack. With his students Boris Podolsky and Nathan Rosen, they made one last valiant attempt to smash the quantum theory once and for all. The EPR paper, named after its authors, was to be the final blow against the quantum theory.
One unforeseen by-product of this fateful challenge would be the quantum computer
Imagine, they said, two electrons that are coherent with each other, meaning they are vibrating in unison, i.e., with the same frequency but shifted by a constant phase. It is well known that electrons have spin (which is the reason why we have magnets). If we have two electrons with a total spin of zero, and if we let one electron spin, say, clockwise, then the other electron spins counterclockwise because the net spin is zero.
Now separate the two electrons. The sum of the spins of the two electrons must still be zero, even if one electron is now on the other side of the galaxy. But you cannot know how it is spinning before you take a measurement. But strangely, if you measure the spin of one electron and find it is spinning clockwise, then you instantly know that its partner on the other side of the galaxy must be spinning counterclockwise. This information traveled instantaneously between the two electrons, faster than the speed of light. In other words, as you separate these two electrons, an invisible umbilical cord emerges between them, allowing communication to travel through the cord faster than the speed of light
But, claimed Einstein, since nothing can go faster than the speed of light, this was in violation of special relativity, and hence quantum mechanics is incorrect. This was the killer argument that disproved the quantum theory, Einstein thought. He rested his case
Today, this principle is called entanglement, the idea that when two objects are coherent with each other (vibrating in the same way), then they remain coherent, even if separated by vast distances
This has major implications for quantum computers. It means that, even if the qubits in a quantum computer are separated, they can still interact with each other, which is responsible for the fantastic computational ability of quantum computers
This gets at the essence of why quantum computers are so unique and useful. An ordinary digital computer, in a sense, is like several accountants toiling away independently in an office, each doing one calculation separately, and handing off their answers from one to another. But a quantum computer is like a roomful of interacting accountants, each one simultaneously computing, and, importantly, communicating with each other via entanglement. So we say that they are coherently solving this problem together
Tragedy of War
Unfortunately, this vibrant intellectual debate was interrupted by the rising tide of world war. Suddenly, the scholarly discussions about the quantum theory became deadly serious, as both Nazi Germany and the U.S. instituted crash programs to develop the atomic bomb. The Second World War would have devastating consequences for the physics community.
Planck, witnessing the wholesale migration of Jewish physicists from Germany, personally met with Adolf Hitler, pleading him to stop the persecution of Jewish physicists, which was destroying German physics. However, Hitler became enraged at Planck and screamed at him.
Erwin Schr?dinger, who witnessed a Jewish man being beaten by the Nazis in the streets in Berlin, tried to stop the attack, only to be beaten himself by the SS.
Chapter 4 DAWN OF QUANTUM COMPUTERS
The transistor is a paradox.
Usually, the larger an invention, the more powerful it is. Huge double-decker jetliners can carry loads of passengers halfway around the world in a matter of hours. Rockets today are towering inventions able to send multiton payloads to Mars. The nearly seventeen-mile-long Large Hadron Collider cost over $10 billion and may one day unravel the secret of the Big Bang. Its circumference is so big that much of the city of Geneva can be put inside the perimeter of the machine
Yet the transistor, perhaps the most important invention of the twentieth century, is so small that billions of them can fit on your fingernail. It is not an exaggeration to say that it has revolutionized every aspect of human society.
So sometimes smaller is better. For example, sitting on your shoulders is the most complex object in the known universe, the human brain. Consisting of 100 billion neurons, each connected to about 10,000 other neurons, the human brain in its complexity exceeds anything known to science
So both a microchip made of billions of transistors and the human brain can be held in your hand, yet they are the most sophisticated objects that we know about
Why is that? Their incredibly small size hides the fact that you can store and manipulate vast amounts of information within them. Furthermore, the way that this information is stored resembles a Turing machine, giving them tremendous calculational power. A microchip is the heart of a digital computer with a finite input tape (though Turing machines in principle can have an infinite tape). And the brain is a learning machine or neural network that constantly modifies itself as it learns new things. A Turing machine can be modified so it too can learn like a neural network.
But if the power of the transistor comes from being microscopic, then the next question is: How small can you make a computer? What is the smallest transistor?
Genius in Action
Richard Feynman was one of a kind. There will probably never be another physicist like him.
On one hand, Feynman was a charismatic showman, fond of amusing audiences with outrageous stories of his past and his crazy antics. In his rough accent, he sounded like a truck driver as he told colorful tales about his life.
Always interested in new, quirky experiences, he once sealed himself in a hyperbaric chamber to find out if he could leave his body and see himself floating from a distance. And he would love to play his bongos at all hours of the day.
Birth of Nanotech
Above all, Feynman was a visionary
Feynman realized that computers were becoming smaller and smaller. So he asked himself a simple question: How small can you make a computer?
He realized that in the future, transistors would become so small they would eventually become the size of atoms. In fact, he conjectured, the next frontier for physics could be to create machines as small as atoms, pioneering a growing field now called nanotechnology.
He realized that in the atomic realm, new fantastic inventions are possible. The current laws of physics that we use on the macroscale become obsolete at the atomic scale, and we have to open our minds to entirely new possibilities. His ideas were first expressed in a speech he gave to the American Physical Society at Caltech in 1959, titled There’s Plenty of Room at the Bottom, anticipating the birth of a new science.
His basic idea was simple: to create tiny machines that could arrange the atoms the way we want. Any tool that we use in our workshop would be miniaturized to the size of fundamental particles. Mother Nature manipulates atoms all the time. Why can’t we?
He summarized his idea for quantum computers by saying, Nature isn’t classical, dammit, and if you want to make a simulation of nature, you’d better make it quantum mechanical.
This is a profound observation. Classical digital computers, no matter how powerful, can never successfully simulate a quantum process
Quantum Sum Over Paths
He realized that in a quantum computer this would have tremendous calculational power. Think of a maze. If a classical mouse were put in a maze, it would tediously try out many possible paths, one after the other, in sequence, which is extremely slow. But if you put a quantum mouse in a maze, it simultaneously sniffs out all possible paths at the same time. When applied to a quantum computer, this principle exponentially increases its power
So Feynman rewrote the quantum theory in terms of the principle of least action. In this view, subatomic particles sniff out all possible paths. On each path he put a factor related to the action and Planck’s constant. Then he summed or integrated over all possible paths. This is now called the path integral approach, because you are adding up contributions from all the paths an object can take
Much to his shock, he found he could derive the Schr?dinger equation. In fact, he found that he could summarize all of quantum physics in terms of this simple principle. So decades after Schr?dinger introduced his wave equation by magic, with no derivation, Feynman was able to unify the entirety of quantum mechanics, including the Schr?dinger equation, using this path integral approach
As a physicist, I work with relativistic versions of Schr?dinger’s equation, which is called quantum field theory, i.e., the quantum theory of subatomic particles at high energies. The very first thing I do when calculating with quantum field theory is to follow Feynman and start with the action. I then calculate over all possible paths to get the equations of motion. So Feynman’s path integral approach, in some sense, has swallowed up all of quantum field theory
But this formalism is not just a trick; it also has some profound implications for life on earth. We saw earlier that quantum computers have to be kept at near absolute zero. But Mother Nature can perform marvelous quantum reactions at room temperature (such as photosynthesis and the fixing of nitrogen for fertilizers). Under classical physics, there is so much noise and jostling of atoms at room temperature that many chemical processes should be impossible in those conditions. In other words, photosynthesis violates the laws of Newton
So how does Mother Nature solve the problem of decoherence, the most difficult problem in quantum computers, to enable photosynthesis at room temperature?
By summing over all paths. As Feynman showed, electrons can sniff out all possible paths to do their miraculous work. In other words, photosynthesis, and hence life itself, may be a by-product of Feynman’s path integral approach
Quantum Turing Machine
In 1981, Feynman emphasized that only a quantum computer can truly simulate a quantum process. But Feynman did not elaborate on precisely how a quantum computer might be built. The next person who picked up the torch was David Deutsch of Oxford University. Among other achievements, he was able to answer the question: Can you apply quantum mechanics to a Turing machine? Feynman had hinted at this problem, but never wrote down the equations for a quantum Turing machine. Deutsch went on to fill in all the details. He even designed an algorithm that could run on this hypothetical quantum Turing machine
In the same way that Turing was able to make the field of digital computers rigorous by introducing the precise rules of Turing machines, Deutsch helped make the foundation of quantum computers rigorous. By isolating the essence of how qubits are manipulated, he helped standardize work on quantum computers
Perhaps the most outrageous of these proposals was made in 1956 by graduate student Hugh Everett. We recall that the quantum theory can be summarized in roughly four broad principles. The last one is the sticking point, where we collapse the wave function to decide what state the system is in. Everett’s proposal was daring and controversial: his theory says simply to drop the last statement that says the wave collapses so it never does at all. Each possible solution continues to exist in its own reality, producing, as the theory is known, many worlds.
Parallel Universes
But not only is Deutsch well known for developing the concept of quantum computers, he also takes seriously the deep philosophical questions raised by them. In the usual Copenhagen interpretation of quantum mechanics, one has to make an observation to finally determine where an electron is. Before an observation is made, the electron is in a fuzzy mixture of several states. But when the state of the electron is measured, the wave function magically collapses down to one physical state. This is how one extracts numerical answers from a quantum computer.
Many Worlds
However, Everett’s and Deutsch’s theories challenge the very nature of reality. The many worlds theory is one that overturns our conception of existence itself. Its consequences are staggering
Unfortunately, Everett’s idea was so radical, so out of this world, that it was uniformly ignored by physicists for decades. Only recently has it experienced a revival as physicists rediscover his work
Rebirth of Parallel Universes
Meanwhile, during the years he was working on nuclear warfare, his ideas began to slowly percolate in the physics community. One problem arose when physicists tried to apply quantum mechanics to the entire universe, i.e., to create a quantum theory of gravity
In quantum mechanics, we start with a wave that describes how an electron can be in many parallel states at the same time. At the end, the observer makes a measurement from the outside and collapses the wave function. But we encounter problems when applying this process to the entire universe
So if you try to apply superposition to the entire universe, then you necessarily wind up with parallel universes, just as Everett predicted. In other words, the starting point of quantum mechanics is that the electron can be in two states at the same time. When we apply quantum mechanics to the entire universe, it means that the universe must also exist in parallel states, i.e., in parallel universes. So parallel universes are unavoidable.
Parallel Universes in Your Living Room
Nobel laureate Steve Weinberg once explained to me how to mentally get your head around the many worlds theory so your mind doesn’t explode. Imagine, he said, sitting quietly in your living room, with radio waves from various radio stations around the world filling the air. In principle, there are hundreds of signals from various radio stations in your living room. But your radio is only tuned to one frequency; it can only pick up one station, because you are no longer vibrating in sync with other radio stations. In other words, your radio has decohered from the other radio waves filling up your living room. Your living room is full of different radio stations, but you cannot hear them because you are not tuned into them, or coherent with them
Now, he told me, replace the radio waves with quantum waves of electrons and atoms. In your very living room, there are the waves of parallel universes, i.e., the waves of dinosaurs, aliens, pirates, volcanoes
David Deutsch takes these mind-boggling concepts seriously. Why are quantum computers so powerful? he asks. Because the electrons are simultaneously calculating in parallel universes. They are interacting and interfering with each other via entanglement. So they can quickly outrace a traditional computer that computes in only one universe
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To demonstrate this, he takes out a portable laser experiment that he keeps in his office. It simply consists of a sheet of paper with two holes in it. He shines a laser beam through both holes and finds a beautiful interference pattern on the other side. This is because the wave has passed through both holes simultaneously, and has interfered with itself on the other side, giving rise to an interference pattern
This is nothing new
But now, he says, gradually reduce the intensity of the laser beam to almost zero. Eventually you have not a wave front, but just a single photon passing through both holes. But how can a single photon of light pass through both holes simultaneously?
In the usual Copenhagen interpretation, before you measure the photon, it actually exists as the sum of two waves, one for each hole. Isolating a single photon has no meaning until you measure it. Once you measure it, then you know which hole it went through.
Everett did not like this picture, because it meant that you could never answer the question: Which hole did the photon enter before we measured it? Now apply this to electrons. In Everett’s many worlds theory, the electron is a point particle that indeed went through just one hole, but there was another twin electron in a parallel universe that went through the other hole. These two electrons, in two different universes, then interacted with each other via entanglement to alter the trajectory of the electron to create the interference pattern.
In conclusion, a single photon can pass through only one slit, but it can still create an interference pattern because the photon can interact with its counterpart moving in a parallel universe
Summary of Quantum Theory
Let’s now summarize all the bizarre features of the quantum theory that make quantum computers possible.
Shor’s Breakthrough
Up until the 1990s, quantum computers were still largely a plaything for theoreticians. They existed in the minds of a small but brilliant core of scientists, true believers, and academics
But the work of Peter Shor at AT&T in the early 1990s changed everything. Far from being a minor footnote talked about casually at water coolers, quantum computers suddenly were on the agenda of major governments around the world. Security analysts, who may have little need for a physics background, were now being asked to decipher the mysteries of the quantum theory.
Everyone who watches a James Bond movie knows that the world, with so many competing and even hostile national interests, is full of spies and secret codes. This may be a Hollywood exaggeration, but the crown jewels of these security agencies are the codes they use to protect their most valuable national secrets. We recall that Turing’s success breaking the Nazi Enigma code was a historic turning point, helping shorten the length of the war and altering the course of human history
Up to then, work on quantum computers was highly speculative and was the domain of the most esoteric electrical engineers. But Shor showed that it is possible for a quantum computer to break any digital code currently in use, thereby jeopardizing the world economy, which requires absolute secrecy when sending billions of dollars over the internet.
The key advantage of a quantum computer is time. Although both classical and quantum computers can perform certain tasks, the time it takes classical computers to crack a difficult problem may make it totally impractical
In other words, both a classical computer and quantum computer factorize in much the same way, except the quantum computer computes over many states simultaneously, which greatly speeds up the process.
So the calculation time can rapidly rise to astronomical heights, comparable to the age of the universe. This makes the factorization of a large number possible but highly impractical on a conventional computer.
But if we do the same calculation using a quantum computer, the time to factorize only grows like t ~ Nn, i.e., like a polynomial, because quantum computers are astronomically faster than a digital computer
Laser Internet
In the future, top secret messages may be sent on a separate internet channel carried by laser beams, not electrical cables. Laser beams are polarized, meaning that the waves vibrate in only one plane. When a criminal tries to tap into the laser beam, this changes the direction of polarization of the laser, which is immediately detected by a monitor. In this way, you know, by the laws of the quantum theory, that someone has tapped into your communication.
So if a criminal tries to intercept a transmission, it will inevitably set alarm bells ringing. It does require, however, a separate internet based on lasers to carry the most important national secrets, which would be an expensive solution
Chapter 5 THE RACE IS ON
Some of the biggest names in Silicon Valley are now placing their bets on which horse will win this race. It’s too early to tell at this point who that might be, but what is at stake is nothing less than the future of the world economy
Similarly, quantum computers can also have a wide range of possible designs. Basically, any quantum system that can superimpose states of 0s and 1s and entangle them so that they can process this information can become a quantum computer. Electrons and ions that spin up or down could serve this purpose, or polarized photons that spin clockwise or counterclockwise. Since the quantum theory governs all matter and energy in the universe, there are potentially thousands of ways to build a quantum computer. In a lazy afternoon, a physicist may dream up scores of ways of representing the superposition of 0s and 1s to create an entirely new quantum computer.
So what do those various designs look like, and what are the advantages and disadvantages of each? As we saw, companies and governments are investing billions in this technology, and their choice of design may influence who will come to dominate this race. So far, IBM is leading the pack with 433 qubits, but like a horse race, the exact rankings can change at any time.
As we go to press, IBM released the 433-qubit Osprey quantum computer and will deploy the 1,121-qubit Condor quantum computer in 2023. Dario Gil, IBM senior vice president and head of its research division, says, We believe that we will be able to reach a demonstration of quantum advantage—something that can have practical value—within the next couple of years. That is our quest. In fact, IBM has publicly stated that its goal is to eventually build a million-qubit quantum computer.
At present, the superconducting quantum computer has set the bar for computing power. Back in 2019, Google was first out of the gate, announcing that it had achieved quantum supremacy with its Sycamore superconducting quantum computer
However, IBM was not far behind, and later surged ahead with its Eagle quantum processor, which broke the 100-qubit barrier in 2021 and has since developed the 433-qubit Osprey processor
The superconducting quantum computer relies on this technology as well. By bringing the temperature down to a fraction of a degree above absolute zero, the circuits become quantum mechanical, i.e., they become coherent, so the superposition of electrons is undisturbed. Then, by bringing various circuits together, one can entangle them so that quantum calculations are possible
However, because it is impossible to actually reach absolute zero, errors will inevitably creep into the calculation. While an ordinary digital computer does not have to worry about this, it becomes a major headache for the quantum computer. It means that you cannot entirely trust the results. This could be a serious problem if billions of dollars in transactions are at stake.
Yet another contender is the ion trap quantum computer. When you take an electrically neutral atom and strip off some electrons, you get a positively charged ion. An ion can be suspended in a trap consisting of a series of electric and magnetic fields, and when multiple ions are introduced they vibrate as coherent qubits
Soon after Google made its claim of achieving quantum supremacy, the Chinese announced that they broke an even larger barrier, performing a calculation in 200 seconds that would take a digital computer half a billion years
When quantum physicist Fabio Sciarrino of Sapienza University in Rome heard the news, he recalled, My first impression was, Wow! Their quantum computer, instead of computing on electrons, computes on laser light beams
Because photonic computers operate at room temperature, their coherence time is quite short. But this is compensated for by the fact that the laser beams can have high energy, so the calculations can be done much faster than the coherence time, so the molecules in the environment appear as if they were moving in slow motion
More recently, a Canadian start-up called Xanadu has introduced its photonic quantum computer, which has a distinct edge. It is based on a tiny chip (not a tabletopful of optical hardware) that manipulates infrared laser light through a microscopic maze of beam splitters. Unlike the Chinese design, the Xanadu chip is programmable and its computer is available on the internet. However, it only has eight qubits, and still requires some superconducting freezers
The big advantage of silicon photonic computers would be that they can use the tried-and-true methods perfected by the semiconductor industry.
One of the keys to their program is the dual nature of silicon. Not only can silicon be used to make transistors and hence control the flow of electrons, it can also be used to transmit light, since it is transparent to certain frequencies of infrared radiation. This dual nature is crucial to entangling photons
One big selling point is that they can address the problem of error correction. Since errors creep into any calculation because of interactions with the environment, you want redundancy built into the system by creating redundant qubits. With a million qubits, they feel that they can begin to control these errors, so that real practical calculations can be done on the computer.
The dark horse in this race is the Microsoft design, which uses topological processors
As we’ve seen, one major problem facing several of the previous designs is that the temperature must be kept near absolute zero. But according to quantum theory, there is another way besides ion traps and photonic systems to create a quantum computer. A system can remain stable at room temperature if it maintains some special topological properties that are always preserved. Think of a circular piece of rope with a knot in it. If you are not allowed to cut the rope, then no matter how hard you try, the knot cannot be removed
There is currently one last type of quantum computing called quantum annealing, being pursued by the D-Wave company, based in Canada. Though it does not use the full power of quantum computers, D-Wave claims it can produce machines that can reach 5,600 qubits, far beyond the number found in other competing designs, and has plans to offer computers with more than 7,000 qubits in a few years
In summary, there is intense competition among corporations and even governments to get a head start on this new technology. The rate of progress in this field has been astounding. Every major computer company has their own quantum computer program. Prototypes are already proving their worth and are even being sold on the marketplace.
But the next big challenge is for quantum computers to solve real-world practical problems that can alter the trajectory of entire industries. Scientists and engineers are focusing on problems that are far beyond the reach of digital computers. The goal is to apply quantum computers to solve the biggest problems in science and technology
One focus of research is to uncover the quantum mechanics behind the origin of life, which will help unravel the mystery of photosynthesis, feed the planet, provide society with energy, and cure incurable diseases.
PART II QUANTUM COMPUTERS AND SOCIETY
Chapter 6 THE ORIGIN OF LIFE
Every culture has its cherished mythology about the beginning of life. People have often wondered what could possibly explain the glorious richness and diversity on earth. In the Bible, for example, God created the heavens and earth in six days. He created man in His image out of dust, and then breathed life into him. He created all the plants and animals to be ruled by us.
The origin of life is perhaps one of the greatest mysteries of all time. This question has dominated religious, philosophical, and scientific discussions like no other. Throughout history, many of the deepest thinkers believed that there was a mysterious life force that could animate the inanimate. Many scientists, in fact, believed in something called spontaneous generation, that life could magically arise by itself out of inanimate matter.
Even today, there are many gaps in our understanding of how life first originated on the earth almost 4 billion years ago. In fact, digital computers are useless when analyzing the fundamental biological and chemical processes at the atomic level that might shed light on this problem. Even the simplest molecular process can quickly overwhelm the capacity of a digital computer. However, quantum mechanics may help explain many of these gaps and unravel the mysteries of life. Quantum computers are ideally suited for this problem and are now beginning to uncover some of the deepest secrets of life at the molecular level.
Two Breakthroughs
Two monumental breakthroughs occurred in the 1950s that have set the agenda for further research in the origins of life. The first occurred in 1952, when a graduate student, Stanley Miller, working under Harold Urey at the University of Chicago, did a simple experiment
Since then, this simple experiment has been repeated and modified hundreds of times, giving scientists a revealing look into the ancient chemical reactions that may have spawned life. One can imagine, for example, that toxic chemicals found in hydrothermal vents at the bottom of the oceans might have provided the basic elements needed to create the first chemicals of life and that these volcanic vents might have then supplied the energy to turn those chemicals into the amino acids necessary for life. Indeed, some of the most primitive cells on earth are found near these underwater volcano vents
Today, we realize how easy it is to create the building blocks of life. Amino acids have been found in distant gas clouds many light-years away, or in the interior of meteorites from outer space. Carbon-based amino acids may form the seeds of life throughout the universe. And all of this because of the simple bonding properties of hydrogen, carbon, and oxygen, as predicted by the Schr?dinger equation.
Thus, it should be possible to apply quantum mechanics to find, step by step, the quantum processes that originated life on earth. Elementary quantum theory helps us understand why the Miller experiment was so successful, and it may point the way toward deeper discoveries in the future.
What Is Life?
The second breakthrough came directly from quantum mechanics. In 1944, Erwin Schr?dinger, already famous for his wave equation, wrote a seminal book, What Is Life? In it, he made the astonishing claim that life itself is a by-product of quantum mechanics, and that the blueprint of life is encoded in an unknown molecule. In an era when many scientists still believed that a mysterious life force animated all living matter, he made the assertion that life can be explained by an application of quantum physics. By examining solutions of his wave equation, he conjectured, life could arise from pure mathematics, in the form of a code handed down through this mystery molecule
It was an outrageous idea. But two young scientists, physicist Francis Crick and biologist James Watson, saw this as a challenge. If the basis of life could be found in a molecule, then their task would be to find this molecule and prove that it carried the code of life.
From the moment I read Schr?dinger’s What Is Life?, I became polarized towards finding out the secret of the gene, recalls Watson.
They reasoned that the molecule of life, as envisioned by Schr?dinger, must be hidden in the genetic material of the nucleus of the cell, much of which is composed of a chemical called DNA
Physics and Biotechnology
One person who spearheaded this effort to sequence all our genes was Harvard biochemist and Nobel laureate Walter Gilbert. When I interviewed him, he admitted to me that this field was not in his original game plan. In fact, he started working at Harvard as a professor of physics, studying the behavior of subatomic particles created in powerful accelerators. Working on biology was the furthest thing from his mind
So he made the biggest gamble of his career
As a professor of physics, he made a huge jump, switching from theoretical elementary particle physics to biology. But the gamble paid off, because in 1980 he won the Nobel Prize in Chemistry. Among other achievements, he was one of the first to develop a rapid technique to read the DNA molecule, gene for gene.
He then helped build momentum for the Human Genome Project. In 1986, when speaking at Cold Spring Harbor in New York, he gave an estimate for the cost of this ambitious, unprecedented endeavor: $3 billion. The audience was stunned, recalled Robert Cook-Deegan, author of The Gene Wars. Gilbert’s projections provoked an uproar. This, many people felt, was an impossibly low number. When he made that startling prediction, only a handful of genes had been sequenced. Many scientists even thought that the human genome would forever be beyond reach.
One person who was deeply influenced by all this is Francis Collins, the former director of the National Institutes of Health. He is one of the most influential doctors in medicine today. Millions of people have seen him on TV talking about the latest developments with the Covid-19 pandemic.
I asked Collins how he became interested in biology, despite starting out as a chemistry major. He confessed to me that biology always seemed so messy, with so many arbitrary names for so many animals and plants. There was no rhyme or reason, he thought. In chemistry, he saw order, discipline, and patterns that could be studied and duplicated. So he taught physical chemistry, using the Schr?dinger equation to explain the inner workings of molecules
Very quickly, Collins made a name for himself. In 1989, he uncovered the gene mutation responsible for cystic fibrosis. He found that it is caused by the deletion of just three base pairs in your DNA (from ATCTTT to ATT).
Eventually, he became the top medical administrator in the country. But he brought his own personal style to Washington. He rode to work on his motorcycle. And he has never shied away from his personal religious beliefs. He even wrote a best-seller: The Language of God: A Scientist Presents Evidence for Belief
Three Stages in Biotechnology
Gilbert and Collins, in some sense, represent some of the stages in the development of this field
In Stage One, Walter Gilbert and others were able to complete the Human Genome Project, one of the most important scientific ventures of all time. However, the catalogue of the human genome is like a dictionary with 20,000 entries and no definitions. By itself, it is a monumental accomplishment, but also a useless one
In Stage Two, Francis Collins and others have tried to fill in the definitions for these genes. By sequencing diseases, tissues, organs, etc., one is able to tediously compile the way in which these genes operate. It is a painfully slow process, but gradually the dictionary is being filled up
But now we are gradually entering Stage Three, when we can use this dictionary to become writers ourselves. This means using quantum computers to decipher how these genes operate at the molecular level, so that we can devise new therapies and create new tools to attack incurable diseases. Once we understand how they inflict their damage at the molecular level, we may be able to use that knowledge to devise new techniques to neutralize or cure these diseases
Whirlwind advances in quantum computers are giving birth to new sciences called computational chemistry and quantum biology. Finally, quantum computers are making it possible to create realistic models of molecules, allowing scientists the ability to see, atom for atom, nanosecond by nanosecond, how chemical reactions take place
Now imagine you could analyze all the ingredients at the molecular level. In principle it might be possible to create new, delicious recipes from first principles, knowing how the molecules all interact with each other. This is the hope of quantum computers, to be able to understand the interaction of genes, proteins, and chemicals at the molecular level.
Researcher Jeannette M. Garcia of IBM says, As molecules get larger, they very quickly get out of the realm of what you can simulate with classical computers.
Elsewhere, Garcia has written that predicting the behavior of even simple molecules with total accuracy is beyond the capabilities of the most powerful computers. This is where quantum computing offers the possibility of significant advances in the coming years. She points out that digital computers can only reliably calculate the behavior of just a couple of electrons. Beyond that, the calculation overwhelms any classical computer, unless drastic approximations are made.
Linghua Zhu at Virginia Tech says, The atoms are quantum, the computer is quantum, we’re using quantum to simulate quantum. When we use classical methods, we always use approximations, but with a quantum computer, it’s possible to exactly know how each atom is interacting with the others.
Chapter 7 GREENING THE WORLD
When I walk in a dense forest on a bright spring day, I can’t help but be overwhelmed by the lush, vibrant green vegetation that surrounds me and the explosion of delicate blossoms everywhere I look. Wherever I gaze, I see this rainbow of vivid colors. I see life bursting out in all directions, with plants eagerly soaking up the sunlight and somehow converting that energy into all this abundance
What drives life on this planet is photosynthesis, the deceptively simple process by which plants convert carbon dioxide, sunlight, and water into sugar and oxygen. It’s staggering to realize that photosynthesis creates 15,000 tons of biomass per second, which is responsible for covering the earth with green vegetation.
Life would be unimaginable without photosynthesis, yet remarkably, with all our advances in science, biologists are still not precisely sure how this vital process occurs. Some biologists believe that, because the capture of a photon of energy by photosynthesis is nearly 100 percent efficient, it must be quantum mechanical
We sometimes forget that photosynthesis is the end product of billions of years of totally random, chaotic chemical processes, and it developed these remarkable properties purely by chance. Hence, once quantum computers unravel the mystery of photosynthesis at the quantum level, we might be able to improve and modify the way plants grow. Billions of years of plant evolution might be squeezed into a few months on a quantum computer.
Photosynthesis is so vital to the earth that it has literally reshaped the planet’s atmosphere
But when photosynthesis emerged on earth, it converted the carbon dioxide into the oxygen we now breathe. So with every breath, I am reminded of this momentous transition that occurred billions of years ago.
Through these means biologists were able to slowly understand the life history of plants. But one step always eluded them. How do plants capture the energy of photons of light in the first place? What starts this long chain of events, beginning with the capture of the energy of sunlight? It remains a mystery to this day. But quantum computers may help unravel it
Quantum Mechanics of Photosynthesis
Many scientists believe photosynthesis is a quantum process. It begins when photons, the discrete packets of light, hit a leaf that contains chlorophyll. This special molecule absorbs red and blue light, but not green, which is scattered back into the environment. Hence, the green color of plants is due to the fact that green is not absorbed by them
When light hits a leaf, you would expect it to be scattered in all directions and lost forever. But here is where quantum magic occurs The photon of light impacts chlorophyll, and this creates energy vibrations on the leaf, called excitons, which somehow travel along the surface of the leaf. Eventually, these excitations enter what is called a collection center on the surface of the leaf, where the energy of the exciton is used to convert carbon dioxide into oxygen
According to the Second Law of Thermodynamics, when energy is transformed from one form to another, much of that energy is lost into the environment. So one expects that much of the energy of the photon should dissipate when hitting the chlorophyll molecule and therefore become lost during this process as waste heat
Instead, miraculously, the energy of the exciton is carried to the collection center with almost no energy loss at all. For reasons that are still not understood, this process is almost 100 percent efficient
This phenomenon by which photons create excitons that pool in collection centers would be like a golf tournament where each golfer fires a ball randomly in all directions. Then, as if by magic, all these balls would somehow change direction and score a hole in one each time. This should not be happening, but it can actually be measured in the laboratory
One theory is that this journey of the exciton is made possible by path integrals, which we saw earlier were introduced by Richard Feynman. We recall that Feynman rewrote the laws of the quantum theory in terms of paths. When an electron moves from one point or another, it somehow sniffs out all possible paths between these two points. Then it calculates a probability for each route. Hence, the electron is somehow aware of all possible paths connecting these points. This means that the electron chooses the path with the most efficiency
There is also a second mystery here. The process of photosynthesis happens at room temperature, where random motions of atoms in the environment should destroy any coherence among the excitons. Normally, quantum computers have to be cooled down to near absolute zero in order to minimize these chaotic motions, yet plants function perfectly well at normal temperatures. How is that possible?
Artificial Photosynthesis
One way to experimentally prove or disprove the existence of quantum effects is to look for indications of coherence, the telltale sign of quantum effects when atoms vibrate in unison. Normally, one would expect to find a chaotic jumble of individual vibrations, without any rhyme or reason, but if one detects some vibrations in phase with each other, this would immediately signal the presence of quantum effects
It might also explain how photosynthesis could operate at room temperature, without all the pipes and tubing found in a physics laboratory.
Quantum computers are ideally suited to making these quantum calculations. If this approach using path integrals is valid, then it means that we can now alter the dynamics of photosynthesis to solve a variety of problems. Instead of conducting thousands of experiments with plants, which takes an inordinate amount of time, these experiments could be done virtually.
Artificial Leaf
When we discuss the world’s biggest problems, CO2 is usually described as one of the villains of the story. CO2 captures energy from the sun and causes the earth to heat up. But what if we could recycle this greenhouse gas so it would become harmless? We might then also be able to create commercially valuable chemicals from recycled CO2. Scientists propose that sunlight may be able to do exactly that. This new technology would take CO2 from the air and combine it with sunlight and water to create fuel and other valuable chemicals, not unlike a leaf, but made artificially. Burning this fuel would create more CO2, which could then recombine with sunlight and water to create more fuel, in a ceaseless process of recycling with no net gain of CO2. In this way CO2, which has been cast as the villain, becomes a useful resource
For this recycling to work, it would proceed in two steps
First, sunlight would be used to break apart water into hydrogen and oxygen. The hydrogen produced could then be used in fuel cells to power clean hydrogen cars. One problem with electric cars is that they use batteries, which, in turn, get their energy mainly from coal- and oil-fired plants
Second, the hydrogen produced by splitting apart water can be combined with CO2 to produce fuel and valuable hydrocarbons. This fuel, in turn, can be burned, and CO2 is again produced, but it can be recombined with hydrogen and hence recycled. This could create a new cycle in which CO2 could be continually reused so it doesn’t build up in the atmosphere, stabilizing the amount of this greenhouse gas while providing energy at the same time.
The hard part is now to complete the final step and find a cheap way to combine hydrogen with CO2 to create fuel. This is difficult because CO2 is a remarkably stable molecule. Harvard chemist Daniel Nocera thinks he has found a viable way to accomplish this. He uses a bacterium, Ralstonia eutropha, which can combine hydrogen with CO2 to create fuel and biomass, with an efficiency of 11 percent.
Quantum computers can take the technology to the next level. So far, much of the progress in this area is done by trial and error, requiring hundreds of experiments with exotic chemicals
If quantum computers provide the final step to creating artificial photosynthesis and the artificial leaf, it may open up entirely new industries that can provide new forms of efficient solar cells, alternate forms of crops, and new forms of photosynthesis. In the process, it might be possible to use quantum computers to find ways to recycle CO2, which would go a long way in the effort to combat climate change.
Chapter 8 FEEDING THE PLANET
In modern history, one man is responsible for saving more lives than any other person on earth, yet his name is largely unknown to the general public. It is reliably estimated that about half of humanity is alive today because of this man’s discoveries, yet there are no biographies or documentaries singing his praises. Fritz Haber, a German chemist, touched the lives of every human on the planet. Haber was the man who discovered how to make artificial fertilizers. Fifty percent of all the food we eat is directly related to his pioneering research, yet his contribution is rarely celebrated by historians.
He unleashed the Green Revolution, breaking open nature’s secrets to manufacture almost unlimited quantities of fertilizer that help feed the planet today. He changed world history when he discovered the crucial chemical process by which nitrogen could be taken from the air to create fertilizers. Where once peasants had to toil in the harsh soil to eke out a miserable living, today we have miles of green crops, as far as the eye can see. Instead of starving nations with barren, lifeless fields, we have lush farms yielding tremendous bounty.
But his role in history is tarnished by the fact that his stunning breakthrough can also be used to create devastating chemical weapons, including high-energy explosives as well as poison gas. Although billions of people on this planet owe their very existence to this man, his work also killed thousands who perished because of the havoc his discoveries unleashed on the battlefield
Furthermore, we have to live with the fact that the Haber-Bosch process, as the technique he developed is known, is so power-hungry that it puts an enormous strain on the energy supply, exacerbating pollution and even climate change
But to appreciate the pioneering work of Haber, and the importance of quantum computers improving on his discoveries, one has to first appreciate his enormous contribution to escape the dismal destiny once predicted by Malthus
Overpopulation and Famine
Today, the world’s food supply is heavily dependent on fertilizers. The essential ingredient of fertilizer is nitrogen, which is found in our protein and DNA molecules. Nitrogen, ironically, is the most plentiful chemical in the air we breathe, making up about 80 percent of it. For some mysterious reason, simple bacteria that can grow along the roots of legumes (e.g., in peanuts and beans) are able to extract nitrogen from the air and fix it with molecules of carbon, oxygen, and hydrogen to create ammonia, the essential ingredient needed to make fertilizer.
These bacteria have somehow mastered a puzzling chemical process. Although common bacteria can effortlessly extract nitrogen from the air to create life-giving fertilizers, chemists are still at a loss to duplicate Mother Nature so efficiently.
The reason is that the nitrogen we breathe in the air is actually N2, i.e., two nitrogen atoms stuck together extremely tightly with three covalent chemical bonds. These bonds are so strong that normal chemical processes cannot break them. So chemists are saddled with this stubborn dilemma. The air we breathe is full of life-giving nitrogen, which in principle makes fertilizer possible, but it is of the wrong form, and hence useless
It is like the proverbial man dying of thirst in an ocean full of salt water. You are surrounded by water but there’s not a drop to drink.
Science for War and Peace
This is where the work of Fritz Haber comes in. Even as a child, he was fascinated by chemistry, often performing experiments by himself. His father was a prosperous merchant importing dyes and pigments, and he would sometimes help in his father’s chemical factory. He was part of a rising generation of European Jews who were successful in business and science, but he eventually converted to Christianity. But above all, he was a nationalist, with a firm desire to help Germany with his knowledge of chemistry
He focused on a number of chemical mysteries, including how to harness the nitrogen found in the air into useful products, such as fertilizer as well as explosives. He realized that the only way to split the two nitrogen atoms apart was to apply enormous pressure and temperature. By brute force, the nitrogen bonds could be broken, he theorized. He made history by finding the right magical combination in the laboratory. If you heated the nitrogen gas found in air to 300 degrees C and compressed it with the pressure of 200 to 300 times atmospheric pressure, then it was possible to finally break the nitrogen molecule apart and have it recombine with hydrogen to form ammonia, which is NH3. For the first time in history, chemistry could be used to feed the world’s rising population
He would win the Nobel Prize in 1918 for this pioneering work. Today, about half the nitrogen molecules in your body are a direct consequence of Haber’s discovery, so his enduring legacy is imprinted in your atoms. The world population today is over 8 billion people, and we could not feed this population without his work
Fertilizers were not the only thing on Haber’s mind. Being a German nationalist, he was an enthusiastic supporter of the German army during World War I, and the energy stored in the nitrogen molecule could be harnessed to create life-giving fertilizer as well as fatal explosives.
So, ironically, the man whose mastery of chemistry expanded the world population also doomed the lives of thousands of innocents. He is also known as the Father of Chemical Warfare
But there is also a tragic aspect to his life. His wife, a pacifist, would commit suicide, perhaps due to her opposition to his research in chemical warfare and poison gas.
ATP: Nature’s Battery
Scientists who are anxious to apply quantum computers to the problem of replacing the inefficient Haber-Bosch process realize that they have to understand how nitrogen fixing is performed by Mother Nature
In order to break the nitrogen bond, Haber’s method was to apply high temperatures and enormous pressure from the outside. This is what makes it so inefficient. But nature does it at room temperature, without high-temperature furnaces and compressors. How can a lowly peanut plant do what usually takes a huge chemical plant?
In nature, the fundamental energy source is found in a molecule called ATP (adenosine triphosphate), which is the workhorse of life, nature’s battery. Whenever you flex your muscles, take a breath, or digest food, you are using the energy from ATP to fuel your tissues. The ATP molecule is so elemental that it is found in almost all forms of life, indicating that it evolved billions of years ago. Without ATP, most of life on earth would die.
In nature, harnessing energy from twelve ATP molecules from random collisions might take years. Clearly this is too slow to make life possible. So a series of shortcuts are necessary to greatly accelerate this process.
Quantum computers may be able to help solve this riddle. They could unravel this process at the molecular level, and perhaps improve the nitrogen-fixing process or find an alternative process
Catalysis: Nature’s Shortcut
The key, scientists believe, is something called catalysis, which may be analyzed with quantum computers. A catalyst is like a bystander. It does not participate directly in a chemical process, but somehow by its presence it facilitates a reaction
Normally, chemical reactions found in the body are quite slow, sometimes taking place over long periods of time. Sometimes, something magical happens to speed up these processes so they can take place in a fraction of a second. This is where catalysts come in. For the nitrogen-fixing process, there is a catalyst called nitrogenase. Like a conductor, its purpose is to orchestrate the many steps necessary to combine twelve ATP molecules with nitrogen to break the triple bond. So nitrogenase is the key to creating a Second Green Revolution. But unfortunately our digital computers are too primitive to unravel its secrets. A quantum computer, however, may be perfectly suited for this important task.
Microsoft is one company that cannot wait to solve the nitrogen-fixing problem. It already is using first-generation quantum computers to see if the mystery of this process can be uncovered. The implications are profound, with the potential to create a Second Green Revolution and feed an exploding world population with lower energy costs. Failure to do so could have disastrous side effects, as we’ve seen, perhaps leading to riots, famine, and wars.
Recently, Microsoft had a setback when some experimental results on topological qubits did not turn out correctly, but for the true believers in quantum computers, that is just a speed bump
In fact, Google’s CEO, Sundar Pichai, recently claimed that he thinks that quantum computers may be able to improve on the Haber process within a decade
Quantum computers will be essential to analyzing this important chemical process, in several ways:
Chapter 9 ENERGIZING THE WORLD
Edison and Ford would pass the time by making wagers, betting on which energy source would power the future. Edison favored the electric battery, while Ford believed in gasoline. For anyone listening to this wager, it was a no-brainer. One would surely conclude that Edison would win handily. Electric batteries were quiet and safe. Oil, by contrast, was noisy, noxious, and even dangerous. The idea of having a gas station every few blocks was considered preposterous
In many ways, the critics of oil were all correct. The fumes emitted by the internal combustion engine can cause respiratory illnesses and accelerate global warming, and gasoline-powered cars are still noisy
But it was Ford who eventually won the bet
People began to forget about Edison’s dream. Inefficient, clumsy, and weak, the electric battery could not compete with cheap, high-octane fuel designed for an energy-hungry population
Because Moore’s law has revolutionized the world economy with cheap computer power, there is a tendency to assume that everything obeys this law. We are puzzled, therefore, by the fact that battery power efficiency has lagged for so many decades. We forget that Moore’s law only applies to computer chips, and that chemical reactions like the ones that power batteries are notoriously hard to predict. Forecasting new chemical reactions that would increase the efficiency of a battery is a major undertaking.
Solar Revolution?
This challenge of increasing battery performance has tremendous economic implications. Back in the 1950s, futurists proclaimed that our houses would one day be powered by sunlight. Vast arrays of solar cells, supplemented with powerful windmills, would capture the energy of the sun and the wind and provide cheap and reliable energy. Energy for free. That was the dream.
In part, the problem lies in the limitations of modern batteries. When the sun does not shine and the winds do not blow, power from renewable energy drops to zero
History of the Battery
Looking back, we see that the history of the battery has moved at a glacial pace across the centuries. In ancient times, it was well known that if one walked across a carpet, you might get an electric shock when touching a doorknob
In 1799, Alessandro Volta built the first battery and showed that he could create a chemical reaction to reproduce this effect. To create electricity in the laboratory on demand was a sensational discovery. News spread quickly that this strange force could now be generated at will.
But sadly, the battery has not changed much in over 200 years. The simplest battery starts with two metal rods or electrodes placed in separate cups. In both cups is a chemical called an electrolyte, which allows a chemical reaction to take place. Connecting the two cups is a tube in which ions can pass from one cup to the other
Lithium Revolution
In the postwar era, battery technology was a backwater field. Progress stagnated because there was relatively little demand for electric vehicles and portable electronic appliances. However, increased concern about global warming and the exploding electronics market has sparked new research in battery technology
Because of the threat of pollution and global warming, the public has demanded action. As pressure mounted on the automobile industry to convert to electric cars, inventors rushed to create more powerful batteries. Batteries were gradually becoming competitive with gasoline.
One success story has been the introduction of the lithium-ion battery, which has taken the market by storm. They are found in nearly all forms of electronics, in cell phones, computers, and even jumbo jetliners. What makes them so ubiquitous is the fact that they have the highest energy capacity of any battery available, yet they are portable, compact, reliable, and efficient. It is the end product of decades of research, painfully analyzing hundreds of different chemicals for their electrical properties
Putting it all together, the lithium-ion battery has an anode made of graphite, a cathode made of lithium cobalt oxide, and an electrolyte made of ether. The impact of lithium-ion batteries has been so revolutionary that the Nobel Prize in Chemistry was given to several scientists who perfected it: John B. Goodenough, M. Stanley Whittingham, and Akira Yoshino
However, one undesirable feature of lithium-ion batteries is that, although they have the highest energy density of any battery on the market, they still have only 1 percent of the energy stored in gasoline. If we are to enter a carbon-free era, we need a battery with an energy density approaching that of its fossil fuel rival.
Beyond Lithium-Ion Batteries
Because of the enormous commercial success of the lithium-ion battery, found everywhere in modern society, there is a feverish search under way for a replacement or improvement for the next generation. Again, engineers are limited by their trial-and-error approach
One such candidate is the lithium-air battery. Unlike other batteries, which are completely sealed, this one allows air to flow in. The oxygen from the air interacts with the lithium, releasing the battery’s electrons
The big advantage of the lithium-air battery is that its energy density is ten times that of the lithium-ion battery, so it is approaching the energy density of gasoline
Despite the enormous boost in energy density found in lithium-air batteries, a host of technical problems have prevented this remarkable battery from working in practice. In particular, it has a short life span of only two months or so. Scientists who have faith in this technology believe that, by experimenting with scores of different types of chemicals, one might be able to solve many of these technical problems
Not surprisingly, the automotive industry is investing in quantum computers to see if a super battery might be designed using pure mathematics. A super-efficient battery could remove the chief bottleneck preventing a Solar Age: the storage of electricity.
The Automotive Industry and Quantum Computers
One company that sees the potential of quantum computers to revolutionize their industry is the automotive giant, Daimler, which owns Mercedes-Benz. As early as 2015, Daimler created the Quantum Computing Initiative to keep abreast of this rapidly changing field
Airbus is using a quantum computer to create a virtual wind tunnel to calculate the most fuel-efficient path in which its airplanes ascend and descend. And Volkswagen is also using this technology to calculate the optimal path for buses and taxis to take in a congested city
But quantum computers are not just useful for creating newer, cheaper, and more powerful batteries and cars, without destroying the environment. Quantum computers may eventually also free us from the dangers of dreaded, incurable diseases that have afflicted humanity since the dawn of time. We now turn to how quantum computers can create a revolution in medicine
PART III QUANTUM MEDICINE
Chapter 10 QUANTUM HEALTH
How long can you live?
For most of human history, the average life expectancy for humans hovered between twenty and thirty years. Life was often short and miserable. People lived in constant fear of the next plague or famine.
With this new orientation among doctors and scientists, the stage was set for revolutionary advances like antibiotics and vaccines, which would eventually vanquish a bestiary of deadly diseases, adding perhaps ten to fifteen more years to the average life expectancy. Better nutrition, surgery, the Industrial Revolution, and other factors also contributed to the increase in life expectancy
So now the average life expectancy in many countries is in the seventies.
Unfortunately many of these breakthroughs in modern medicine were due to luck, not careful design. There was nothing systematic about finding cures for these diseases, which occurred mainly through fortuitous accidents
For example, in 1928, when Alexander Fleming inadvertently observed that particles of bread mold could kill bacteria growing in a Petri dish, he set off a revolution in health care. Doctors, instead of helplessly watching their patients die of common diseases, could now give antibiotics like penicillin, which, for the first time in human history, could actually cure the patient. Soon, there were antibiotics against cholera, tetanus, typhoid, tuberculosis, and a host of other diseases. But most of these cures were found by trial and error
Rise of Drug-Resistant Germs
Furthermore, as humanity expands into previously unexplored and unpopulated areas, we are constantly exposed to new diseases for which we have no immunity. So there is a huge pool of unknown diseases waiting to jump out and infect humanity.
Some believe that the large-scale use of antibiotics in animals has accelerated this trend. Cows, for example, become breeding grounds for drug-resistant germs because farmers sometimes overadminister antibiotics in order to increase milk and food production
Because of the threat that these diseases may come back stronger than ever, there is an urgent need for a new generation of antibiotics that are cheap enough to justify their cost. Sadly, there has been no development of new classes of antibiotics for the last thirty years. The antibiotics that our parents used are about the same ones we use today
Role of Quantum Medicine
Today, using automation, robotics, and mechanized assembly lines, thousands of Petri dishes containing different types of diseases can be exposed to promising drugs all at once, mimicking the basic approach pioneered by Fleming 100 years ago
Since then, our strategy has been:
Test promising substance?→?determine if it kills bacteria?→?identify the mechanism
Quantum computers might upend this process entirely and accelerate the search for new lifesaving drugs. They are powerful enough that one day they might guide us systematically to new ways to destroy bacteria. Instead of spending ages fiddling with different drugs over many decades, we might be able to rapidly design new drugs inside the memory of a quantum computer
This means reversing the order of the strategy:
Identify the mechanism?→?determine if it kills bacteria?→?test promising substance
Killer Viruses
Similarly, modern science has been able to attack viruses using vaccines, but only up to a point. Vaccines work indirectly by stimulating the immune system of the body, rather than by directly attacking the virus, so progress to cure diseases caused by viruses has been slow
Since then, vaccines have been used against a large number of previously incurable diseases, such as polio, hepatitis B, measles, meningitis, mumps, tetanus, yellow fever, and many others. There are thousands of possible vaccines that might have therapeutic value, but without an understanding of how the body’s immune system works at the most minute scale, it is impossible to test all of them
Covid Pandemic
One way to see the power of quantum computers is to consider the tragedy of the Covid pandemic, which has killed about a million people in the U.S. so far and plunged billions of people around the world into economic hardship and distress. Quantum computers, however, can give us an early warning system to detect emerging viruses before they spawn a worldwide pandemic
Early Warning System
There are several ways in which quantum computers can help stop the next pandemic. At the very least, we need an early warning system to detect the virus as it emerges in real time. From the moment a new version of the Covid-19 virus emerges, it takes weeks before an alert can be issued. During that period the virus can escape unnoticed into the human ecosystem. A delay of a few weeks can allow the virus to spread to millions of people
One method for tracking epidemics is to put sensors in sewer systems around the world. Viruses can easily be identified by analyzing the sewage, especially around crowded urban areas
One theory is that the Mardi Gras celebration in late February 2020 in New Orleans was a superspreader event that exposed hundreds of thousands of unsuspecting people to the virus. Sure enough, when analyzing the thermometer readings right after Mardi Gras, one can see a sudden spike in patient temperatures in the South
In the future, with a vast network of medical devices like thermometers and sensors connected to the internet, one might have an instantaneous temperature readout of what is happening around the country analyzed by quantum computers. With a simple glance at the map of the country, one can see hotspots representing a potential new superspreader event.
So in the future, a network of sensors placed indoors might be able to detect aerosols in the air and then send the results to quantum computers, which can analyze this vast pool of information to find the early warning signs of the next pandemic.
Deciphering the Immune System
Vaccines have proven that the body’s own immune system is a powerful defense against infectious disease. But scientists know very little about how it actually works.
In the future, quantum computers may provide an unprecedented look into the molecular biology of the immune system. This may present numerous ways in which to turn off or dial down the immune system so it does not kill you in the event of a serious infection
The Future
Antibiotics and vaccines are the foundation of modern medicine. But antibiotics are usually found by trial and error, and vaccines only stimulate the immune system to create antibodies to fight off a virus. So one of the goals of modern medicine is to develop new antibiotics, and another is to understand the body’s immune response, which is our first line of defense against viruses and also one of the greatest killers of all time, cancer. If the mystery surrounding our immune system can be solved using quantum computers, then we will also have a way to attack some of the greatest incurable diseases, such as certain forms of cancer, Alzheimer’s, Parkinson’s, and ALS
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