A Look Into Quantum Computing

Understanding the What and Why of Quantum Computing

Published July 3, 2019in Computation6 min read

Imagine a classical computer (your laptop, phone, etc.) as a Formula One race car and a quantum computer as an unknown type of race car. If the two cars were to race on a track, the quantum computer would speed past the Formula One, but rather, take a secret shortcut to the finish line seconds after the race starts. However, if you were to open the hood of the quantum car, it would collapse into just a random component, like a v8 engine. This quirkiness of quantum mechanics is very interesting and has the potential to change computing as we know it today

Counting in 0s and 1s

Let’s breakdown the analogy in terms of computing and science. To understand this, we must first understand how a computer works. A classical computer performs elementary functions. At the core of all those functions are transistors, a physical switch which can either block or allow data through it. The Formula One race car, representing classical computers, work by programming the most basic form of data, bits. Bits are binary, meaning they can either be 0 or 1, reflecting the states of “on” or “off.” Bits are programmed to encode and process data. A combination of bits is used to represent more complicated pieces of data. Then transistors combine to form, logic gates, which then connect to develop modules which can carry out simple operations, such as add two numbers. Upon being able to add, computers are also able to multiply as multiplication is repeated addition.

In reality, children would be much more inclined to play, rather than doing some math.

The operations performed by the machine are so basic that they would likely be questions on the test of a grade 2 student (ex. 2 x 5 or 10 + 2). You can even imagine a computer as an army of grade 2 students, working as a unit to solve math questions. Upon having more students, they can do anything from performing astrophysics calculations to running complex AI programs.

Problems Ahead

The process described above has become increasingly complicated as computer parts start to shrink. Apple’s iPhone X s was one of the first to start using 7 nanometers (nm) transistors in their chips and Apple is aiming to use 5nm chips in their 2020 iPhones. To provide context, the diameter of an HIV cell is 120 nm, and a red blood cell is 7000 nm. Since transistors are just an electrical switch, they merely block electrons from moving in one direction. With the size of transistors shrinking to the size of mere atoms, electrons may transfer themselves to the other side of the blocked passage, causing all sorts of unpredictable things to occur. This process of particles transferring themselves is called Quantum Tunneling. The process creates a significant barrier for classical computers going ahead. Thus, scientists decided to utilize the power of quantum physics to build quantum computers.

0s, 1s, and Everything In Between

Quantum computers are based off qubits, the quantum computer counterpart to bits. In the quantum world, qubits do not have to either be a 1 or a 0. Instead, they exist in any proportion of both states at once. However, once it passes through a filter or has its value tested, it becomes vertically or horizontally polarized. This process causes the qubit to collapse into one of the definite states. This phenomenon is called superposition and is truly a game changer. As long as a qubit is left unobserved, it will be in a superposition of probabilities for 0 and 1, and it is impossible to predict which it will be. Superpositioning explains how whatever was underneath the hood of the quantum car, collapsed into a v8 engine in the race car analogy.

So Quirky!

Four classical bits can be in one of 16 different configurations at a time. That provides 16 possible combinations, out of which you can only use one. However, four qubits in superposition can be in all 16 of those combinations at once. This number grows exponentially with each extra qubit and with only 20 qubits, it is possible to have over a million combinations at once. Quantum computers also have many more quirky and unconventional properties, such as entanglement and qubit manipulation using quantum gates.

But Why Quantum Computers?

Even though quantum computers won’t be replacing our computers at home anytime soon, they are already showing positive signs in the realm of database searching, optimization problems, simulations and exploiting IT Security.

When searching a query, a classical computer (the type you are reading this article on) would have to test every one of its entries in a database until it reaches the one that matches with the given query. Whereas, quantum algorithms running on quantum computers would only need the square root of the time required by classical computers, making it exponentially faster.

Also, quantum computers have recently been getting attention regarding IT security. This rising interest is due to quantum computers ability to completely exploit today’s security infrastructure. Currently, banking data, emails and other confidential data are kept secure by an encryption system, which uses a public and private key. The public key encodes messages and private key, which only you have, can be used to decode the message. Classical computers would take years to try and crack the private key; however, quantum computers could potentially calculate the private key in a matter of minutes.

Also, the realm of simulations is quite exciting for quantum computers, as simulations based on quantum physics are hugely resource intensive on classical computers, while sometimes lacking in accuracy. This is where quantum computers come into the scene, as it would be logical to simulate quantum physics using processors based on quantum mechanics.

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In the very words of the renowned physicist Richard Feynman, “Nature isn’t classical, dammit, and if you want to make a simulation of nature, you’d better make it quantum mechanical.”

The Los Alamos National Laboratory used D-Wave Quantum Computers for quantum molecular dynamics simulations. The results were shown to equal or beat methods that exist today. (Learn More)

Due to the very nature of quantum computers, they are much better at solving optimization problems. Optimization problems revolve around trying to find the best combination of things given some constraints. Classical computers rely on a large number of switches to find the optimal solution. However, these switches are not scalable, which is not ideal when solving real-world problems with large data sets. Quantum computing is already being deployed to solve a variety of optimization problems today. One of the most exciting of which is solving a problem that my family faces daily — traffic jams. In 2017, the Volkswagon Group used quantum computers from quantum computer maker D-Wave to calculate traffic flows and optimize travel time of 10,000 taxis in the city of Beijing. (Learn More)