When should you worry about investing time and energy in understanding quantum computing?

Quantum computing is a truly exciting emerging technology. It is a new type of computing that provides a fundamentally new way of solving computations. Quantum computing creates new ways to approach computational problems that classical computers have problems with modeling the natural world. (Read our full guide here.)

How quantum computing differs from traditional computing

In short, traditional computers only have one state, and quantum computers have multiple states, which means a quantum computer can do multiple computations simultaneously. A quantum computer uses the properties of quantum mechanics to perform operations on data, potentially creating a completely new computing paradigm. It uses different hardware and different software to do calculations in a fundamentally different way to traditional computers. Quantum computers can run a whole new set of algorithms, which means that for some calculations it can take powerful computational shortcuts.

Quantum computers make use of qubits, which are roughly analogous to the traditional computing bit. A qubit carries quantum information; unlike a conventional bit, it can be used to show multiple states. A quantum computer uses this property and quantum entanglement (the way quantum particles interact) to store and process computations. Exploiting this creates the ability to conduct the multiple calculations simultaneously, like having a massive number of perfectly integrated parallel processors.

A quantum computer is not fast for everything. It requires a type of calculation that takes advantage of the simultaneous calculation ability. It is all about the algorithm.

Is practical quantum computing still just an impractical experiment with any stable use decades away?

This is the quadrillion dollar question, particularly given quantum computing’s not-passing resemblance to other over-hyped transformative technologies such as nuclear fusion and room-temperature superconductors—dreamt up in the golden age after the World War II, without a tangible endpoint, but with the seemingly constant promise of a miraculous breakthrough just over the horizon in spite of massive investment. The analogy seems particularly relevant given that current quantum computers need superconductors and the insane supercooling that currently goes with them to operate. To many, quantum computers remain expensive, impractical flights of fancy, fuelled by journalistic research hyperbole.

So, is it safe for you to laugh in the face of any minion that utters the phrase “Maybe we should invest in some quantum?” Unfortunately, the answer is not so simple. The trouble is that no one knows the actual timeframe. Even John Preskill, the Richard P. Feynman Professor of Theoretical Physics at CalTech, can’t give you a firm prediction. Forecasts range from single to multiple decades, and the current wave of “noisy” quantum experiments is unlikely to have much practical use. However, you need to weigh this uncertainty against a serious risk—a practical or at least partially practical quantum computer could have dire consequences for traditional encryption.

Part of the excitement around the prospect of quantum computing is the first algorithm made to run using a quantum computer could solve the mathematical factoring equation very quickly. This solution can be used to rapidly break existing methods of encryption like RSA and ECC.

Is quantum computing just about encryption?

This isn’t an April Fools’ joke. Quantum computing is a serious business. When it finally becomes a practical reality, it will have far-reaching implications, particularly for anyone researching at an atomic level. Given that every aspect of the quantum computing journey can be comfortably described as nascent, we can’t predict with any certainty what the technology will bring. The problem with quantum is the number of uncertainties, which is not limited to the number of qubits:

• Current quantum computers are little more than experiments (no offense), with practical run times lasting less than two minutes. Although researchers have claimed as many as 72 qubits, the lack of stability causes obvious issues.
• The number of qubits required to do anything is not clear at the moment. Equations exist that predict how many qubits will be needed to solve current encryption codes, focusing on the number of bits in the encryption, but there is disagreement about even these.
• The error rate of current quantum computers means that the number of qubits you can use is much less than the number you have, so the computers require redundancy. It’s not worth getting into detail here—but this means multiples of the number qubits on top of the predicted number may be required to compensate for the errors.
• The creation of more algorithms that benefit from quantum. This is one area where research may deliver some results, particularly using quantum simulators.

The Bottom Line: Don’t panic! Quantum computing will be used to un-crack the scientific conundrums not passwords

Cracking today’s hard encryption is the tip of the iceberg. But even this is not something to panic about because even if a breakthrough occurs, the on-ramp for the technology is staggering. Firstly, quantum computers are likely to be working on decoding the universe rather than decoding people’s bank accounts or medical records. Secondly, the expense of the initial technology will be prohibitive (to say the least) and the initial quantum resources will be very precious. Plus, the solution to quantum decryption exists; it means encryption methods will once again have to improve, just like they did with the rise of digital computing.

You should be seriously considering quantum investment if your business has R&D focused at the atomic level. You are probably already looking at quantum computing—if not, then it should be on your radar. The potential of the first generation of noisy quantum computers will have implications for development work at the nuclear level. There is also the potential for breakthroughs in chemical and materials science, so quantum computing should be on the watch list of any R&D department that is using high-performance computing. We will be publishing another article that looks at the “almost” quantum computers which are becoming available.