When you hear the phrase “Quantum Physics”, you think of names like Max Planck, Albert Einstein and Stephen Hawking. You also think it’s a realm of science that’s very difficult to understand.
Quantum computing is just as hard to grasp. When you delve into the details, it sounds like something from out of science fiction but actually, it’s something that all the major tech companies are working on right now.
Classical computing is what we’re all familiar with. Every year, laptops and PCs are becoming faster, slimmer and cheaper. This is due to a phenomenon called Moore’s Law which allows computer chip makers to pack in about double the number of transistors in a chip every two years or so.
Moore’s Law has held up remarkably well for decades but at some point, it will come to an end. It has to as we will someday reach a physical limit on how many transistors (now shrunken to a size smaller than bacteria) can be placed on a chip. To have faster computing after that day requires a paradigm shift in the way computing is done. And that’s where quantum computing comes in.
In classical computing, one bit of binary data can have one of two values: 1 or 0. In quantum computing, units of data are called qubits and each of these can exist simultaneously as both 1 and 0. In other words, these two bits can be entangled, which allows quantum devices to conduct calculations in parallel.
It’s a bit difficult to picture the differences but to use a spherical analogy, a classical computing bit can be at either of the two poles of the sphere whereas a qubit can be at any point on the sphere.
In classical computing when you add an extra transistor to your computer’s processor, you can encode just one more piece of binary information. In quantum computing, each additional qubit actually doubles its encoding capacity.
Qubits operate according to two key principles of quantum physics: superposition and entanglement. Superposition means that each qubit can represent both 1 and 0 at the same time. Entanglement meanwhile, allows particles to be manipulated despite the distance between them so that anything that happens to one particle will be reflected in the other.
These two principles allow quantum computers to solve more complex problems in quicker time than classical computing. With just 50 or so qubits, quantum devices would already be able to do things beyond what today’s super-computers can do.
This is great. So why don’t we have quantum computers in the market already? It so happens that controlling these complex systems of qubits is quite a challenge. The quantum effects of superposition and entanglement are very fragile. The system is so fragile that so far scientists have been able to keep qubits in a stable state for just a fraction of a second. After that errors start occurring. But all the major tech players are working on this so we should see some breakthroughs in a few years’ time.
This month Intel announced that it has successfully built a 49-qubit processor codenamed “Tangle Lake”, which is quite remarkable given that just last October it revealed it had made a 17-qubit chip. In just three months, it has managed to play catch up with the likes of Google and IBM which has been working on this for years.
Google has been testing a 22-qubit quantum computer and has a 49-qubit model in development. Last November, IBM announced that it has a 50-qubit device in its labs. “This 49-qubit chip pushes beyond our ability to simulate and is a step toward quantum supremacy, a point at which quantum computers far and away surpass the world’s best super-computers,” said Intel CEO Brian Krzanich.
In order for quantum computers to be useful, there needs to be software to run on it. This is where software giant Microsoft comes into the picture. Industrial quantum computers do not exist yet so Microsoft has released cloud-based simulators that allow developers to test software developed in Q#, its programming language for quantum computing.
Q# is not the only quantum programming language. Others such as QCL and Quipper also exist. Quantum programming languages are necessary because the languages used for classical computers simply won’t work for quantum devices. As mentioned earlier, classical computers encode information in binary form as a sequence of 1’s and 0’s, whereas quantum computers use qubits which encode 1’s and 0’s simultaneously.
WHAT CAN THEY BE USED FOR?
Assuming that quantum computers will become commercially available in a few years’ time, what can they be used for? IBM has said they could lead to revolutionary breakthroughs in materials and drug discovery, the optimisation of complex man-made systems and artificial intelligence. “We expect them to open doors that we once thought would remain locked indefinitely,” the company declares on its IBM Q (its quantum computing division) website.
Researchers expect quantum computing to be particularly useful in the medical field, for example, to analyse microbes so they can create new vaccines. Quantum computing can also be useful for DNA sequencing and the search for new types of drugs.
Other commercial applications include improving transportation. Volkswagen is working on a quantum computing platform that’s able to alert drivers to traffic jams 45 minutes before they actually occur. This isn’t possible with classical computers as they lack the processing power needed to accurately analyse situations with as many variables as traffic jams. But quantum computing can do it.
It can also help to accurately predict future demand for public utilities like electricity. Imagine if city councils could use these systems to predict years in advance which neighbourhoods will have households with electric vehicles (which will consume a lot more electricity — perhaps five times more — than normal households). This would facilitate better planning for the funding and deployment of additional power grids.
Of course, like any other advanced technology, quantum computing can be used for nefarious purposes too such as hackers using it to break powerful encryption. At the same time, corporations and governments can work towards building a more secure Internet — perhaps even a quantum Internet — where information is transmitted with cryptography so advanced it will foil quantum hackers.
In other words, we probably will see the same kind of battle between good and bad that exists in today’s Internet landscape. Perhaps it’s true what they say — that the more things change, the more they stay the same. Some things never change, at least with regard to the good and bad that comes with the Internet. But that’s life.
Oon Yeoh is a consultant with experiences in print, online and mobile media. reach him at firstname.lastname@example.org