The second revolution in quantum physics.
Text: Dominik Zumbühl
Quantum physics promises to deliver revolutionary new technologies such as the quantum computer – with far-reaching consequences for the economy and society. For many years, the University of Basel has been playing a pioneering role in quantum research.
In the first third of the 20th century, physicists such as Max Planck, Albert Einstein, Erwin Schrödinger, and Werner Heisenberg fundamentally changed the way we understand nature. With the development of quantum mechanics, a theory was emerging that would challenge human understanding and intuition. Its pioneers were simultaneously astonished and bewildered, and used thought experiments to try to illustrate the paradoxical consequences of the new theory. In the most famous example, Schrödinger describes a cat that, according to the laws of quantum physics, is alive and dead at the same time. However absurd ideas like this may seem, quantum theory is now seen as one of the greatest achievements in science and has revolutionized the way we see the world.
Over the last 20 years or so, quantum physics has given rise to a second revolution. With a steady stream of new experiments, scientists have shown that we can use the crazy world of quantum physics to do useful things that would be impossible in classical physics.
Today, highly sensitive quantum sensors allow us to measure magnetic fields faster and more accurately than ever before. In the near future, quantum physics could pave the way for secure communication channels. In the past, medical diagnostic devices such as magnetic resonance imaging (MRI) scanners have been developed based on the laws of quantum physics.
A computer for completely new problems
Quantum physics offers breathtaking potential for innovation. Against this backdrop, physicists at the University of Basel are pursuing the vision of a computer that takes advantage of the laws of quantum mechanics.
A quantum computer can perform a large number of computing operations in parallel. It is therefore incredibly fast and solves problems in a matter of hours that would take today’s supercomputers billions of years. Whereas the latest supercomputers contain a billion transistors, a quantum computer would contain a billion quantum bits (qubits). While classical bits can adopt only states of 0 or 1, qubits allow you to define more than just two states. In the future, their sheer computing power could allow us to answer questions we have not even dared to ask yet. It is conceivable, for example, that we will be able to create molecules and therefore materials with previously unknown properties: new types of pharmaceutical active substances, for example. Or superconductors for transporting electricity without loss at room temperature. Or chlorophyll-like substances that convert sunlight into useful energy. Until now, innovative substances tended to be discovered by chance. However, in the future, quantum computers could allow scientists to design materials with desirable properties in a targeted manner.
The quantum computer is a highly promising innovation. Its realization is now the subject of work by leading researchers from Harvard to Tokyo. One promising implementation is based on an idea, formulated 20 years ago by the physicist Daniel Loss, that the angular momentum (spin) of individual electrons can be used as the smallest information carrier in a quantum computer. In laboratories around the world, qubits of this kind are considered the most promising candidates for building a quantum computer. The idea’s originator, Daniel Loss, works in Basel and devotes his time to developing a Basel qubit. Manufactured from a semiconducting material, this qubit is extremely small and fast. As silicon is a thoroughly tried-and-tested material for computer chips, silicon qubits offer key advantages over other qubit concepts. Developing a qubit is the overarching objective of Basel’s physics department, where 12 professors are channeling the expertise of their research teams into achieving this common goal.
Basel researchers lead the field
Let me state clearly the magnitude of the challenge: the Department of Physics at the University of Basel is not an industrial laboratory seeking to build a quantum computer in the next few months or years. Rather, we are carrying out research on the foundations of the quantum computer. Research of this kind is very time-consuming but has the potential to bring about genuine innovations. It is worth remembering that, after the transistor was discovered in 1947, it took half a century for personal computers and mobile phones to make their way into our everyday lives and to turn the world of work upside down. With regard to the quantum computer, the marathon has only just begun. Today, companies like Microsoft, Google, and Intel are pinning their hopes on the quantum computer as they realize that the increasing miniaturization of classical CMOS chips is reaching its limits. Basel’s ambition is to be among the front-runners.
So far, we’ve been making great progress. In recent years, Basel’s physicists have secured eight of the prestigious grants from the European Research Council (ERC), with the last two going to our professors Jelena Klinovaja and Ilaria Zardo. This success demonstrates the excellence of our research portfolio. Many young researchers are attracted to the brilliance of the quantum research carried out in Basel. Operating since autumn 2016, the PhD school for “Quantum Computing and Quantum Technologies” currently brings together 20 doctoral researchers. In addition, generous support from the Georg H. Endress Foundation will allow us to set up a cross-border postdoc cluster in cooperation with the University of Freiburg from January 2018. As a result, there will be ten additional scientists working in the field of quantum computing. This initiative is modeled on foundations in the US that provide funding for postdocs at top centers of research.
Collaboration with industrial partner IBM
There are some critical decisions that we currently have to make in the field of quantum physics in order to further strengthen this strategic focus at the University of Basel. These include participation in the EU’s billion-euro flagship project on quantum technologies, which is planned to begin next year. At present, we are preparing an application for a National Centre of Competence in Research (NCCR) from the Swiss National Science Foundation with Basel as the leading house on the topic of scalable quantum computing.
For this NCCR, we have chosen the IBM Zurich Research Laboratory as our main, coleading partner, together with other universities as partners. Our goal is to build silicon spin qubits. In 12 years, the ambitious target is to have a fully scalable logical qubit consisting of ca. 15 physical qubits. Although this is not yet a complete quantum computer, it does provide a copy-paste blueprint for a quantum chip.
When the first concepts for a quantum computer emerged, they did so in Europe. With this as our starting point, we now have the opportunity to build the foundation of a new Silicon Valley. Research on the quantum computer is an investment in a future technology and therefore in Switzerland’s industrial base. Our laboratories are also currently home to a rising generation of experts who can understand, shape and disseminate this emergent technology. Only with their help can we succeed in turning the second revolution of quantum physics to the advantage of society as a whole.
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