Quantum computing gets complicated. The reason? Physics at the subatomic (i.e. quantum) level gets complicated. So complicated that I've been devoting the majority of my free time over the past few days, posting few articles in the intervening period, while I attempted to wrap my head around exactly how this stuff works (at least in broad strokes - I obviously didn't become a particle physicist in a few days time) well enough to explain it to others.
Now that I understand (well, as well as you can without a degree in particle physics) I'm even more excited and concerned than I was before.
The implications of what quantum computers will be able to do are enormous and paradigm shattering. Scientists can't even imagine what will be possible in the age of quantum computers.
Their creation and supremacy belong alongside A.I., VR/augmented reality, and DNA manipulation and categorization tech (such as CRISPR) as things that will shape the future of human civilization.
How Do Quantum Computers Work?
The big change in quantum computers is that they don't work based on a bit, like conventional computers of this day and age do. They work instead using a unit of information called a qubit, short for quantum bit. If you're wondering about precisely what the difference is you might want to check out my first article in this series here.
So when we ask the question 'how to quantum computers work?' what we're really asking is 'how do qubits work?' because this is the main and most significant difference between quantum computers and classical ones. Incidentally, if you are wondering how conventional computers work in the first place, you might want to check out my series of articles here (it's a link to the last article in the series, but scroll to the bottom and you'll see links to the rest).
Alright Then.... How Do Qubits Work?
The short answer to this question is 'very differently'. The long answer to this question is very long, a bit disorienting, and may make you question all you hold to be true. Also it's more than a little complicated (though I'll do my best to simplify). So, strap in.
In the first part of this series of articles we talked about how a qubit can do something that a bit can't: namely, it can be more than one value at a time. Now, before we even begin I have to make sure you understand that this does not mean a quantum computer can give any more answers than a conventional one can.
What it can do is ask many questions at the same time.
Those questions are represented by qubits and manipulations of qubits, but because of the nature of physics on the quantum level, these qubits always collapse down to the same amount of answers as a classical computer.
Somethine else I should make abundantly clear is that physicists, especially quantum physicists, like to talk in abstractions and metaphors. In classical computing a bit is represented by the computer pulses inside of a computer whose strength lets us know whether it is a zero or a one. In the same way a qubit is merely a mathematical representation of the actual physical component being manipulated on a subatomic level. Qubits can be photons, electrons, or ions but, regardless of what they are, they are mathematically equivalent. It's sort of like whether you have two apples or two giraffes or two cars, they can all represent two.
What Is Quantum Supremacy?
Quantum supremacy is when quantum computers are able to equal or surpass classical computers in computing power. This supremacy would make quantum computer unimaginably better than conventional ones at certain types of computing. As it turns out, some of the things that make quantum computing so unimaginably strong also make them somewhat weak.
However, we'll be discussing that what I hope will be the final post of this series, coming soon.
