What is Quantum Computing?

What is Quantum Computing? I get asked this question from our partners all the time now.

I love reading Jeff Barr's blogs as they explain tech in a simple way!

Ordinary (classical) computers use collections of bits to represent their state. Each bit is definitively 0 or 1, and the number of possible states is 2n if you have n bits. 1 bit can be in either of 2 states, 2 bits can be in any one of 4 states, and so forth. A computer with 1 MiB of memory has 2(8*1048576) states, excluding CPU registers and external storage. This is a large number, but it is finite, and can be calculated.

Quantum computers use a more sophisticated data representation known as a qubit or quantum bit. Each qubit can exist in state 1 or 0, but also in superpositions of 1 and 0, meaning that the qubit simultaneously occupies both states. Such states can be specified by a two-dimensional vector that contains a pair of complex numbers, making for an infinite number of states. Each of the complex numbers is a probability amplitude, basically the odds that the qubit is a 0 or a 1, respectively.

A classical computer can be in just one of those 2n states at a given time, but a quantum computer can occupy all of them in parallel.

If you have been in IT for any length of time, you know that Moore’s Law has brought us to the point where it possible to manufacture memory chips that store 2 tebibytes (as I write this) on a thumb drive. The physical and chemical processes that make this possible are amazing, and well worth studying. Unfortunately, these processes do not apply directly to the manufacture of devices that contain qubits; as I write this, the largest gated-based quantum computers contain about 50 qubits. These computers are built on several different technologies, but seem to have two attributes in common: they are scarce, and they must be run in carefully controlled physical environments.

Read more here in Jeff Barr's Blog!