You might have heard talks about quantum computers, which makes it sound and apparently look like talks of the supercomputer during the first generation of supercomputers. Just like the first supercomputer they are big and an impressive piece of hardware capable of doing a lot of calculation.
[Flickr (CC BY-ND 2.0)IBM Research]Source: Quantum Computer Mixing Chamber
The quantum computing of today is a whole different level of computing which directly leverages the fundamentals of quantum mechanics (physics) to make its computation. The physicists amongst us are already familiar that the quantum mechanics are one of the fundamental laws of the universe since it shows the principle behind how everything in the universe work.
The researchers, creators and innovators in this field created computers that put to use these fundamental laws of quantum mechanics.
It harnesses such mechanical phenomena like the wave-particle duality, tunnelling, and entanglement.
One of the people making these efforts is the D-Wave System, a Canadian company who since 2011 when they produced their first quantum computer has since have projects that they are working on with industry giants like Google, NASA, Lockheed Martin, and the Los Alamos National Library.
Everything in Between, and 1s and 0s
The standard computer which you may probably be reading this article with is made to work following the principles of the Turing Machine. The Turing machine works on the principle of manipulation of the smallest information known as bits using a binary system in which the outcome could be a 1 or 0.
But in quantum computing, the quantum bits, called qubits, can exist in more than two states. It can either exist as 0, 1 or an overlap (superposition) of 0 and 1. That means the point at which it is neither 0 or 1 counts as a deciding value for a particular outcome. This added state is part of the beauty of quantum computing that makes it quite a fascinating subject.
The traditional computers work at a task one after the other. Or in the case of the high-speed types, lots of different computation happens simultaneously as separate tasks.
The superposition capability of the quantum computers gives it an almost magical computing prowess that gives it the ability to handle a million computations at a time! This superposition or multi-state qubit feature in quantum computers accords them their inherent parallelism.
For instance, a 30-qubit quantum computer can operate at ten teraflops (trillions of floating-point operations per second). You will notice a significant superior computing power when you compare this with a traditional desktop computing speed which is in gigaflops (billions of floating-point operations per second).
The Quantum Entanglement
That is an aspect of quantum mechanics which assumes that an attempt to determine the subatomic value of a particle may result in a change in its value. For instance, a check on the qubit's state in superposition may either show a value of 1 or 0 which essentially turns the quantum computer into the traditional computer.
In order not to upset the measurement, the scientists figured out a way to indirectly achieve the measurement. In quantum physics, a force applied to two atoms gets their properties entangled. The first atom can take on the characteristic of the second atom. The effect is a change in first atom's value, or position will affect the second entangled atom's value in the opposite direction without the need for the scientists to check on each one individually.
This relationship between the two qubits gets more complicated with the addition of more qubits. The correlations increase exponentially. For instance, for n-qubits, the correlations are 2n
For the D-Wave 2000Q there are 2048 qubits in the QPU.
At the beginning of the computation in the D-Wave 2000Q system, there will be the 22048 different states at the same time. A result is an astounding number of calculations that it can take. Also, a little increase in the number of qubits gives an exponential capability to the quantum computer.
As you increase the number of qubits, the number of those correlations grows exponentially: for n qubits, there are 2n correlations. This number quickly explodes: to describe a system of 300 qubits you'd already need more numbers than there are atoms in the visible Universe. SOURCE: PLUS MAGAZINE
Little wonder Albert Einstein describes entanglement as "spooky action from a distance".
An Environmental Problem
Making a quantum computer that works in the standard environment is difficult if not impossible. The temperature is a factor, the D-wave 2000Q quantum computer operates at a temperature a fraction off 0 Kelvin( near absolute zero), at less than 15 millikelvin or 0.15 Kelvin. At this frigid temperature, which is 180 times colder than interstellar space, the quantum processing unit can now optimally function quantum mechanically.
The second environment problem is the problem of interference from molecules moving around which can cause difficulty to the quantum computation. These interferences include the gamma rays and electromagnetic interference from radio waves, etc.
The extreme cold environment plus layers of shielding insulate and protect the chips in the QPU.
Why go the extreme length of this quantum computing?
From the cost of it which runs in millions to the exotic rarified temperatures, what is it about quantum computing that makes scientists go to all the troubles?
The quantum computer and classical computer can are like the relationship between an aeroplane and a horse. Both are means of transport, while one uses the air and is fast, the other runs on a road at a slower pace.
Quantum computing has an exponential speedup over classical computing for any specific set of problems.
The researchers working on critical human-scale projects like the development of cancer drugs; modelling of cancer to study the attack on cells, big data analysis where large data are analysed with hope to pinpoint patterns and draw inferences from it. The risk management modelling are all applications that quantum computers can handle more efficiently than the classical computers.
The term classical may sound a bit out of place here, but considering the computer as we have it today still does computation following an almost 60-70 years ago computer architecture. Though there has been the tremendous improvement in its use, it has its limits, and the quantum computer is here is take up that slack.
Conclusion
In the future, the quantum computers might change the way we do computing, from the artificial intelligence to the human genomics.
Just barely two decades ago in 1998, the first single qubit was successfully analysed by Michele Mosca and Jonathan A. Jones at Oxford University. In less than two years later, in March 2000, scientists at Los Alamos National Laboratory showcased an upgraded version of the prototype which is a 7-qubit quantum NMR computer.
In 2015, D-Wave broke into the 1000-qubit barrier which leaves many reeling from the 21000 possibilities the new capability opens. The D-wave partners like Google, NASA, etc. currently use these quantum computers.
But it looks like a new era of exponential growth in capacity is here as the D-wave annouced a 2000-qubits system in Jan of 2017.
If you feel like replacing the classical PC that you have, D-Wave can make that happen for a princely sum of $15,000,000. Make room for a 10-foot x 7foot x 10 foot (L x W x H) plus a provision for a 25KW which I think is not so much of a big deal since a traditional supercomputer consumes 2,500 KW.