The second revolution in quantum physics

In the first third of the 20th century, physicists such as Max Planck, Albert Einstein, Erwin Schrödinger and Werner Heisenberg put our understanding of nature on a new footing. Quantum mechanics was a theory that put the human imagination to the test. Their masterminds were amazed and disturbed at the same time. In thought experiments, they tried to illustrate the paradoxical consequences of the new theory. In the most famous one, Schrödinger describes a cat that – if you follow the laws of quantum physics – is alive and dead at the same time. As absurd as such considerations may seem, quantum theory is now considered a central achievement of modern science. It has revolutionized our view of the world.

For about twenty years, quantum physics has been causing a second revolution. Scientists are constantly demonstrating with new experiments: We can use the crazy world of quantum physics to do useful things with it that we were not able to do with classical physics. Highly sensitive quantum sensors now make it possible to measure magnetic fields faster and more accurately than ever before. In the near future, quantum physics could make tap-proof communication channels possible. Medical diagnostic devices such as magnetic resonance imaging had already been developed earlier, which are based on the laws of quantum physics.

A calculator for completely new questions

Quantum physics has a breathtaking potential for innovation. Against this background, physicists at the University of Basel are pursuing the vision of a computer that makes use 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 within hours that would take billions of years for today's supercomputers. While current top-of-the-range computers contain one billion transistors, a quantum computer would contain one billion quantum bits (qubits). While classical bits can only assume the state 0 or 1, qubits can be used to define more than just two states. In the future, their sheer computing power could provide answers to questions that we have not even dared to ask before. It is conceivable, for example, that we can create molecules and thus materials with previously unknown properties: novel pharmaceutical active ingredients, for example. Or superconductors for the loss-free transport of electricity at room temperature. Or chlorophyll-like substances that convert sunlight into usable energy. So far, innovative substances have been discovered rather by chance. Thanks to quantum computers, scientists will be able to specifically design materials with desired properties in the future.

The quantum computer is a great promise. First-class research teams from Harvard to Tokyo are working on its implementation. One of the foundations of their work is an idea formulated twenty years ago by physicist Daniel Loss: The angular momentum (spin) of individual electrons should be used as the smallest information carrier of a quantum computer. In laboratories around the globe, such qubits are considered promising candidates for building a quantum computer.

The originator of the idea, Daniel Loss, works in Basel. Here he is working on the development of a Basel qubit. Made from a semiconductor material, this qubit is extremely small and fast. Silicon is a well-proven material for computer chips, so silicon qubits have decisive advantages over other qubit concepts. The development of a qubit is the overarching objective of Basel physics. Twelve professors are working towards this common goal with the know-how of their research teams.

Basel researchers are in the top group

Let there be no misunderstanding: The Department of Physics at the University of Basel is not an industrial laboratory that will build a quantum computer in the coming months and years. We conduct basic research. Such research takes a lot of time, but has the potential to produce real innovations.

As a reminder: After the discovery of the transistor in 1947, half a century passed before personal computers and mobile phones found their way into our everyday lives and ploughed up our working world. The marathon with a view to the quantum computer has only just begun. Companies such as Microsoft, Google and Intel are now relying on the quantum computer because they realize that the increasing miniaturization of the classic CMOS chip is reaching its limits. Basel has the ambition to run in the top group.

So far, we are well on our way. In recent years, Basel physicists have been awarded eight of the prestigious ERC grants from the European Research Council, the last two by our professors Jelena Klinovaja and Ilaria Zardo. The funding commitments attest to the highest level of our research.

The luminosity of Basel's quantum research attracts many young researchers. The doctoral school "Quantum Computing and Quantum Technologies" has been in existence since autumn 2016 and currently brings together 20 doctoral students. Also thanks to the generous support of the Georg H. Endress Foundation, we will be able to set up a cross-border postdoc cluster with the University of Freiburg from January 2018. Ten additional scientists will work in the field of quantum computing. This initiative is based on the model of US foundations that finance postdocs at top research sites.

The first concepts for a quantum computer were developed in Europe at the time. On this basis, we have the opportunity today to lay the foundations for a new Silicon Valley. Research on quantum computers is an investment in a technology of the future and thus in Switzerland's industrial foundation. In addition, a generation of experts is growing up in our laboratories who can understand, handle and communicate this future technology. Only with them can it be possible to make the second revolution in quantum physics fruitful for society.

source : The Second Revolution in Quantum Physics | University of Basel (unibas.ch)