At the start of a quantum leap

Quantum computers are a focus of attention right now, and for good reason: now we know that they work! It has been said that quantum computers have now evolved from a physicist’s dream to an engineer’s nightmare. There is more than a grain of truth in this, there are still plenty of challenges to overcome.

– We already know how a quantum computer works. Now there is a competition on who will build a more efficient machine and how to scale it up to a larger size, observes Pekka Pursula, Research Manager at VTT Technical Research Centre of Finland.

VTT, IQM and CSC are taking part in this race and in December 2020 started building a quantum computer environment based on superconducting qubits. This first Finnish quantum computer is to reach 50 qubits in 2024. VTT and IQM are building the computer and together with CSC, a supercomputer ecosystem to which the quantum computer can eventually be connected is being set up.

The quantum leap is made possible by amazing strides in accuracy of control and measurement. The idea of quantum computing was conceived already at the break of the 1980s by Paul Benioff, Yuri Manin and Richard Feynman. Practical quantum applications also have a long history: an integrated transistor on a silicon chip, magnetic resonance imaging, and optic fibers (laser is a quantum mechanical phenomenon). The acceleration steps preparing for the leap have been taken for a long time.

The first serious approach towards the takeoff board was in 2011 when D-Wave announced the first rendition of a quantum computing device, the quantum annealer. The height and length of the leaps have increased rapidly since then. In 2019, Google’s Sycamore quantum computer reached quantum supremacy – a point at which a quantum computer calculated something significantly faster than any traditional supercomputer could ever achieve. In 2020, the Chinese Jiuzhang photonic quantum computer repeated the trick using a quantum device based on different technology.

The strange laws of quantum mechanics

The strange laws of quantum mechanics run rampant in quantum computers. The secret for the dazzling speed of a quantum computer lies in taming the quantum strangeness by exploiting the quantum counterparts of our ordinary classical bits, that is, the qubits. Being much more versatile than ordinary bits, the qubits of a quantum computer can be 1 and 0 and everything in between at the same time. When qubits are in this kind of a superposition, all the possible inputs they represent can in a sense be carried out simultaneously, while in classical supercomputers the inputs would be calculated individually. In theory it would be possible to use more quantum states than the qubits’ 0 and 1. For example, a qutrit would comprise three different states.

The coming quantum revolution makes it possible to solve certain types of problems very efficiently. A quantum computer gives only one answer to each calculation, regardless of the number of inputs, however. It is thus suitable for tasks that are optimization tasks by nature – finding a single optimum answer from many “wrong” answers. A classic example is the problem of the traveling salesperson trying to find the shortest route that connects the cities to visit. Only the optimal route, or something sufficiently close to it, is of interest.

Mikko Möttönen (Aalto, VTT, IQM Chief Scientist) who was named Innovation Professor of the year 2021, presented the quantum computer of Aalto University’s QCD laboratory. This quantum computer comprises control electronics kept at room temperature with many wires going into a cooler (cryostat). The quantum processor inside the cryostat is cooled to 10 mK, just a hundredth of a Celsius degree above absolute zero. The qubit is on a silicon chip and is controlled along reading and guidance lines.

Alongside the manufacture of quantum computers, we need to think about how to use and program them.

– A quantum computer can be programmed using quantum gates – commands that modify the state of qubits. A challenge is to utilize the qubits’ feature of being in many different states at the same time in a useful manner. It is also necessary to suitably combine both traditional and quantum algorithms, as quantum computers will be linked with supercomputers. Graphics cards originally developed for video games have become a part of supercomputers. In the same way, GPU accelerators will be accompanied by QPUs in the future, says Mikael Johansson, strategist for quantum technologies at CSC.

Quantum technology is a boost for high-tech companies

In addition to science, companies will also benefit from the coming age of quantum computing. Practical examples of using quantum computing have been demonstrated for example in the car industry. BMW has optimized its subcontracting chain and VW has made calculations of the optimization of transport. At the seminar, the role of a quantum computer in the world of business was discussed by the Finnish Minister of Economic Affairs Mika Lintilä, together with Cristina Andersson, consultant, Develor Productions, Tua Huomo, Executive Vice President of VTT, and Olli Hatakka, QuantumKarelia project leader.

– We face an all-encompassing change and great opportunities. Artificial intelligence, high-performance computing, and quantum computing have become key factors in solving some of the greatest problems facing humanity. How can we get companies interested in high-performance computing and GPU-accelerated computing? What about a quantum leap for businesses? asks Mika Lintilä, in his opening of the seminar.

An ecosystem of its own is taking shape around quantum technology, giving a genuine boost to high-tech enterprises. It would be good to get small innovative start-up companies involved in the development as well, even if they are not yet capable of big investments.

– It is crucial to build skills and knowledge in the field. Strong traditional software know-how provides a good foundation. Through training and education, quantum computing can be enabled to its fullest, Mikael Johansson emphasizes.

– Quantum technology can boost productivity and create new leaps of innovation. Finland could be turned into quantum software hub, says Tua Huomo.

• Watch the Kvantilla Tulevaisuuteen! (By Quantum to the Future!) webinar online (in Finnish)

Mikael Johansson
The author is observing and enabling the quantum technologies at CSC.

Tommi Kutilainen
The author has a few decades of experience in scicomm at CSC and he is especially interrested in everything. Twitter: @TommiKutilainen