Quantum revolutions on Department Day
- Institute for Theoretical Physics (ITP)
- Institute for Quantum Electronics (IQE)
Twice a year, the management of the Department of Physics at ETH Zurich organizes events for all members of the department: the Department Day in June and the New Year's aperitif in January. These are great opportunities for the approximately 500 members of the department to come together and hear the latest news from the department management and from the research groups.
With their talks on the second quantum revolution, ETH Professor Renato Renner and Dr. Karan Mehta provided insights into two of the 46 research groups — the Quantum Information Theory group and the Trapped Ion Quantum Information group. The two speakers had no easy task at hand, given their very mixed audience: office managers, financial specialists, technology enthusiasts, physicists. The two lectures were well aligned: one offered an introduction, the other started with formulae.
How intuitive are quantum phenomena?
Renato Renner gave a lively introduction to the world of quantum phenomena. For example, he asked the audience which trajectory they would expect for a suitcase dropped from the hold of a flying aircraft (see picture below). This example demonstrates that also in classical physics intuition cannot always be relied on.
More than 100 years ago, in the first quantum revolution (which proceeded in several stages of development up to the turn of the millennium) one thing became clear: At these very small scales, almost everything behaves contrary to intuition, contrary to what we know from our daily experience. We therefore often perceive quantum phenomena as 'spooky'.
What can quantum phenomena be used for?
These unexpected phenomena of the quantum world should also be harnessed in the second quantum revolution. Many applications emerged from the findings of the first quantum revolution, such as lasers, GPS, CD players and mobile phones. The second quantum revolution is based on the fact that by now individual atoms, ions and photons can be controlled, manipulated and used for storing information. Professor Renato Renner expects that in the near future today's encryption methods can be broken with the help of quantum computers. This will in particular affect cryptocurrencies such as Bitcoin.
He, in turn, uses the properties and interaction of individual photons to make encryption secure against such attacks. These encryption methods work according to completely different rules than conventional protocols. For example, codes are generated only upon receipt. Before that, they do not exist and therefore cannot be read.
Future quantum-computation technology
It is still unclear which technology will prevail when it comes to the hardware of future industrially manufactured quantum computers. In his presentation, Dr. Karan Mehta presented an overview over the approaches currently pursued at the Department of Physics at ETH Zurich and worldwide, highlighting two of them that have attracted a lot of attention: on the one hand, superconducting units of quantum information (qubits), currently used by IBM and Google, and on the other hand ions, which Mehta works with in the research group of Prof. Jonathan Home. Other groups in the Department of Physics are exploring platforms such as nuclear spins, photons, quantum dots and vacancies in solids. A big challenge on the way to the quantum computer in all variants is the expansion (scaling up) of the systems.
Ions as carriers of quantum information have interesting properties in this regard, explained Karan Mehta: They are all inherently identical, can be moved individually and be controlled very precisely. He sees great potential for the future of this approach, which motivates him to work on this system.
The world is not sleeping
The issues outlined in the lectures are in the focus of intense research activities around the world. All players, especially China and the US, strive to be at the forefront. Enormous resources are flowing into this research area. In addition to quantum physics also other relevant basic research direction are pursued at the Department of Physics.
Management of funds is therefore one of the main challenges on the departmental level. In his introduction at the start of the Departmental Day, the Head of Department, Prof. Rainer Wallny, reported on five strategic research initiatives (ETH+ initiative) prepared by the professorship, to be sent to the ETH Executive Board. They show how existing research reserves could be used effectively to fulfil also in the coming years the basic mission of research, teaching, knowledge and technology transfer. The renewal of the resource and finance platform will give academic units more flexibility in managing their finances from January 2019 onwards.
From quantum physics to Swiss sausages
After all this intense theoretical diet, the traditional departmental barbecue was ready. Also this year, the internal organizing committee has done all they could to ensure that the many hungry mouths did not have to wait long before sitting in front of a full plate. And the relaxed festive atmosphere, outdoors on the Hönggerberg campus, fostered discussion and exchange of new ideas.