Quantum Computing

Computers have been changing the way our world works since they were invented. They have advanced us and helped us become the global society we are today. They have also been advancing themselves from huge computers with basically no power, to computers we have today which can run simulations of galaxies. The next step in this computational evolution is quantum computing.

Basic computing we know today, such as the laptop you're reading this on, works by using a series of 0's and 1's to relay commands. What this means is everything your computer does is controlled by either a 0 or a 1 and whichever digit is selected controls a different response. This is using classical mechanics, because the digit being used is either a 0 or a 1, but can never be both (keep in mind a computer is doing thousands of things at a time, so its not just one digit, its thousands). As a result, large calculations and computations can be very time consuming. Quantum computing utilizes the uncertainty principle associated with quantum mechanics. What I mean by this is instead of all commands being done by either a 0 or a 1, every command uses both 0 and 1 at the same time.

Using this property of quantum mechanics, the computer can make each entry both 0 and 1 at the same time because the digit is like Schrödinger's Cat, the famous thought experiment. For this thought experiment, imagine a cat is placed in a closed box with no windows or anything to observe the box's contents. Placed in the box with the cat is a vile of poison set to open randomly at any moment once the box is closed. When the box is shut, there is no way to know if the cat is dead or alive without opening the box and observing its contents, so until the box is opened the cat can be thought of as both dead and alive. This applies to computing because the computer can operate using both 0 and 1 at the same time because the digit is always 0 and never zero, and it is always 1 and never 1 all at the same time.

This isn't the easiest concept to come to grips with, knowing one things can be 2 different things at the same time, but using it could make computers exponentially faster. Instead of taking time to sift through every command that comes to a computer and doing it all in order, a quantum computer would be able to do thousands of commands and calculations in a split second, almost infinitely fast. And because everything is taking place at the same time, the more calculations you add do not add more time to the process. It would also greatly reduce the size of computers, or at least the computational piece of a computer. Instead of needing a processing chip like we have now, a quantum computer would only need a few atoms to complete the quantum process.

The unprecedented speed and size of quantum computers certainly makes them a prize of the future, and has astounding possibilities of what they could create. For example, since a quantum computer makes every calculation at once, this means it has the possibility of making every calculation imaginable at once, without even being told to. Such as if we had a  quantum computer make a random passage of words, it would simultaneously make every passage of words that would every or has ever or could every be written, because they are all possibilities. 

The sheer power of quantum computing is intriguing, and at the uWaterloo, I will be experiencing its development first hand. On campus, the newly built QNC, or Quantum Nano Centre seen here, is focusing primarily on the development of quantum computers. In association with the Perimeter Institute for Theoretical Physics, some ground breaking work is being done in the field and you and I may be reading this blog on a quantum computer sooner than you think.