The quest for quantum energies in computing
Tags: Science, Quantum Computing, Computer Science, Technology, Algorithms

The beginning of 2019 was marked with IBM announcing its first commercial quantum computer at the 2019 Consumer Electronics Show (CES). Even though experts are quite skeptical about its power and viability, it is a big step forward in the computer building technology. In this post we’ll discuss why it is so important and what we can expect from it.

What is a quantum computer?

A quantum computer is a computation device that makes direct use of quantum mechanical phenomena, such as superposition and entanglement, to perform operations on data. Quantum computers differ from traditional computers based on transistors and more innovative computing technologies such as DNA, optical, or biocomputers.

How does it work?

Quantum computers take advantage of the ability of subatomic particles to exist in more than one state at any time. This ability allows operations to be done much more quickly and use less energy than classical computers.

While in classical computing, a single piece of information is a bit existing in two states — 1 or 0, quantum computing stores information in ‘qubits’. These quantum systems also have two states, but they can storage capacity is not limited to 1 or 0, because they can exist in any superposition of these values.

To manipulate information, quantum computers leverage different physical phenomena — superposition, entanglement, and interference.

Superposition is a combination of states we would ordinarily describe independently. In our everyday life, a superimposition will be the sound of two notes played at once. In quantum superposition, the difference is what happens when you perform a measurement. Even though the system exists in a perfectly defined superposition state, when you perform certain measurements on it, you get random outcomes. So, the magic is observed as a special kind of quantum randomness.

Entanglement is a famously counter-intuitive quantum phenomenon that we never see in the classical world. Entangled particles behave together as a system in ways that cannot be explained using classical logic. In the simplest terms, they cannot be described independently of each other. If we measure one of them, we might observe that it behaved randomly, but it tells us what to expect when measuring the other particle, in the same way. Moreover, this perfect correlation remains true even if you measure entangled particles at opposite ends of the galaxy, so it is crucial for speeding up computation.

Interference is another challenging principle of quantum theory. When particles exhibit interference, they are behaving like waves: when two waves are in phase, their amplitudes add, and when they are out of phase, their amplitudes cancel.

Quantum algorithms

Just like in classical computing, you need an algorithms — a set of instructions that are supposed to solve the problem and you need a machine to execute these instructions. The fact that quantum computers can create superpositions, entanglement, and other quantum effects means that we have to write algorithms in a new way incorporating these phenomena.

We suggest you to watch this explanation by IBM researcher David Gosset to conceptualize it faster and more effectively:

What are the benefits?

At present, there exist challenges above a certain size and complexity that we cannot solve since we don’t have enough computational power on Earth to tackle them. For them we need a new kind of computing: one whose computational power also scales exponentially as the system size grows. If large-scale quantum computers can be built, they will solve certain problems exponentially faster than any of our current computers.

For example, integer factorization is believed to be computationally infeasible with for large integers that are the product of only a few prime numbers. Contrary to classical computers, a quantum computer could solve this problem efficiently using Shor’s algorithm to find its factors.

At present, it is the difficulty of integer factorizations that is the basis of most of public key ciphers. Therefore, a quantum computer will potentially “break” many of the current cryptographic systems.

Shor’s algorithm

From a less sinister perspective, quantum computers can be used to model complicated chemical reactions. Since Google and IBM have already presented quantum devices to simulate a hydrogen molecule and then even more complex molecules, there is hope that quantum simulations will eventually be used to design entirely new molecules for use in medicine.

Furthermore, the Holy Grail for quantum chemists is to model the Haber-Bosch process — a way of artificially producing ammonia.

Do we have a winner?

For quite a time it was believed that Google was leading the race. In a Nature article published in March 2017, it revealed ambitious plans to commercialize quantum technology in the next five years. At the same time, Google intended to achieve the ‘quantum supremacy’ — the point where a quantum computer can crunch sums that a classical computers fail hopelessly — with a 49-qubit computer by the end of 2017.

In November 2017, however, Google’s leadership was shaken by IBM that announced it had built a 50-qubit quantum computer. Yet, it was far from stable, and the system could only hold its quantum microstate for 90 microseconds, far from the times needed to make quantum computing viable.

However, since 2016, long before creating a standalone computer, IBM has been offering a free and publicly available IBM Q Experience that currently has over 100,000 users, who have already run more than 6.7 million experiments resulting in publishing more than 130 research papers. The IBM Q Network has recently included such additions as Argonne National Laboratory, CERN, ExxonMobil, Fermilab, and Lawrence Berkeley National Laboratory.

Similar efforts were taken by such startups as Rigetti focusing on the stability of its own systems and the Canadian company D-Wave that created what it was calling a 2,000-qubit system.

Finally, this January IBM seems to win the race with launching, Q System One, the first standalone commercial quantum computer. But is it a real victory?

Even though IBM describes it as “the first fully integrated universal quantum computing system designed for scientific and commercial use”, it is merely a 20-qubit machine that is not powerful enough for most of the commercial applications. IBM itself stresses that this is a first attempt and that the systems are “designed to one day tackle problems that are currently seen as too complex and exponential in nature for classical systems to handle.”

However, the most important features of it are stability, repeatability and flexibility, and if the underlying architecture of the Q System One is scalable, new processors can be popped in when they’re developed without new engineering challenges.

It is true that right now the Q System One is the quantum equivalent of the room-sized computers of the 1950s. And of course, it is true that getting quantum computing into the hands of consumers will require a big breakthrough to handle high temperatures, at the very least. Still, quantum computers can one day revolutionize many disciplines, such as materials and drug discovery, AI and complex systems optimization, and the present-day IBM announcement is a big step from the fantasy world to our reality.