The Standard Model and the Bird/Frog Perspective of the Universe - part I
It became customary to say the Universe is made of particles, but, guess what, quantum physics does indeed reverse that. Quantum physics emphasizes that the whole comes first [1], not the parts. The parts appear as a fragmentation of the whole. Surprisingly, this wholeness became "the elephant in the room" for many physicists. In my humble opinion, wholeness makes the Universe magnificent, more thrilling than the other way around.
Cosmologist Max Tegmark explains, "The theory becomes easier to grasp when one distinguishes between two ways of viewing a physical theory: the outside view of a physicist studying its mathematical equations, like a bird surveying a landscape from high above it, and the inside view of an observer living in the world described by the equations, like a frog living in the landscape surveyed by the bird."
Welcome back to a new edition of our monthly newsletter which is envisioned as a venue where a broader audience can get exposed to calculations in Theoretical Particle Physics. In the last edition, we discussed the Higgs mechanism, a generation mechanism of the property called "mass" for gauge bosons. This edition will attempt to ponder the Standard Model from the Bird's Perspective.
Let's get started.
Many Branches
If we take mathematics of quantum mechanics at its face value, during a measurement, that is just an interaction of the observer and the observed object, the observer gets entangled [1] or "twisted together" with the observed object. When the object is in a quantum superposition such as a particle being "half here and half there", the observer splits into two copies. One copy of the observer observes the particle "here". The other copy observes the particle "there". So, in a nutshell, the observer himself splits into a number of observers, each of which sees a definite result of the measurement. This is how elegantly Hugh Everett [2] solved the measurement problem and introduced the "many-worlds" concept into the quantum mechanic's vocabulary. The key to understanding this is that the observer does not necessarily mean a conscious observer. When two electrons interact with each other, they "observe" each other.
Continuing on this path we arrive pretty quickly to the conclusion that every quantum process [1] results in a multitude of "observers", witnessing each possible outcome, living in their separate individual realities or "Everett branches". Every quantum transition taking place on every star everywhere in the Universe is splitting our local world on Earth into a humongous number of copies of itself. Splitting makes the Universe mind-boggling, we could say almost a living entity, which constantly splits itself. Everett said, "Our amoeba does not have a life line but a life tree." This is in a nutshell what is called Everett's interpretation of quantum mechanics, usually labeled "Many Worlds" interpretation of quantum mechanics which is, I would say, unfortunate.
The "Many Worlds" label implies Many Universes which, in my humble opinion, is an illusion. The better label would be "Many Branches" since, as Levy-Leblond said [1], "To me, the deep meaning of Everett's ideas is not the coexistence of many worlds, but on the contrary, the existence of a single quantum one." The defining feature of Everett's interpretation is that it describes the Universe exclusively and completely in quantum mechanical terms. There is one Universe, a single quantum mechanical system which, we could say, eternally splits itself into myriad copies of itself.
The Universe as "a clock"
The French polymath Pierre-Simon Laplace [3] hatched a thought experiment known as Laplace's demon. His argument went as follows: if some hypothetical ultra-intelligent being – or demon – could somehow know the position of every atom in the universe at a single point in time, along with all the laws that governed their interactions, it could predict the future in its entirety. We would think we made free choices, but the demon would have known it all along, by extrapolating out along the endless chain of causes. “For such an intellect,” Laplace said, “nothing could be uncertain, and the future, just like the past, would be present before its eyes.” This idea of a deterministic Universe was a natural progression of the success of Newton's mechanics, his law of universal gravitation, which could predict the behavior of both terrestrial objects and the Solar System. It evolved into the concept of the Universe as a system that behaves and operates as a mechanical clock [4].
Do you really think that a deterministic Universe would be an exciting place? Once you are able to predict the future of the Universe in its entirety, the Universe will become a really boring place, sterile from any excitement.
I definitely prefer "Everett's Universe" so to speak, a forever exciting to explore, single quantum mechanical system that continuously splits itself into myriad copies of itself.
The Bird Perspective of the Universe
From the bird's perspective [1], there are no Everett's branches, to begin with. All that exists is a single, entangled quantum Universe. We arrive at this wonderful picture of the Universe if we listen carefully to the mathematics of quantum mechanics. Hugh Everett did. Application of quantum mechanics to the entire Universe enables entanglement to merge the Universe into an all-encompassing "One". It seems old Tai Chi Masters realized this a long time ago when they insisted to be "one with the Tao (Universe)".
Everett said [1]: "The question is one of terminology: to my opinion, there is but a single (quantum) world, with its universal wave function. There are not "many worlds", no "branching", etc., except as an artifact due to insisting once more on a classical picture of the world." As Levy-Leblond emphasizes, "many worlds" describe classical realities we are familiar with, a left-over of classical conceptions, in obvious contradiction of Everett's original intent - the existence of a single quantum Universe. The fundamental reality is not only a single quantum Universe but a single unique entity comprising matter, space, and time as well as all potentially possible events and situations, everything you can and cannot imagine. Not only is there a single quantum world, but this single world is all there is. As Wojciech Zurek affirmed, "It was Everett who gave us the permission to think about the universe as wholly quantum mechanical."
How would the Standard Model look from the Bird's Perspective of the Universe?
We can probably get some clues from quantum computing. In quantum computing [5], we try to exploit the collective properties of quantum states, such as superposition and entanglement, to perform computation. The devices that perform quantum computation are quantum computers. These are really machines that tap into the "One" to perform calculations simultaneously in different parallel worlds (branches).
Everett’s Many Worlds interpretation of quantum mechanics may elegantly explain the inner workings of quantum computers. In David Deutsch’s view [6], "Everett’s approach was to look at the quantum theory and see what it actually said, rather than hope it said certain things. What we want is for a theory to conform to reality, and, in order to find out whether it does, you need to see what the theory actually says. Which with the deepest theories is actually quite difficult, because they violate our intuitions." Deutsch writes [1], "When a quantum factorization engine is factoring a 250-digit number, the number of interfering universes will be of the order of 10 to the power of 500... All those computations are performed in parallel, in different universes, and share their results through interference.''
It seems a very short possible answer to the above question is to try to express the Standard model in terms of quantum computation, which is, of course, easy to say than to do...
Part II will deal with the Standard Model from the Frog's Perspective.
Stay well!
References
[1] The One
[2] https://cqi.inf.usi.ch/qic/everett_phd.pdf
[3] Laplace's demon
[5] https://en.wikipedia.org/wiki/Quantum_computing
[6] https://www.newyorker.com/magazine/2011/05/02/dream-machine