Illustration: Harald Ritsch

This year, physicists in Innsbruck have realized the first quantum simulation of lattice gauge theories, thereby, building a bridge between high-energy theory and atomic physics. The joint research work of Rainer Blatt’s group of experimental physicists and Peter Zoller’s team of theoretical physicists has been recognized by the British magazine Physics World as one of the ten most important breakthroughs in physics in 2016.

Gauge theories describe the interaction between elementary particles, such as quarks and gluons, and they are the basis for our understanding of fundamental processes. However, dynamical processes, such as the collision of elementary particles or the spontaneous creation of particle-antiparticle pairs, are extremely difficult to investigate and scientists quickly reach a limit when processing numerical calculations on classical computers. For this reason, it has been proposed to simulate these processes by using a programmable quantum system. This is what the researchers at the University of Innsbruck and the Institute for Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences accomplished several months ago for the first time. Blatt’s and Zoller’s research groups simulated the spontaneous creation of electron-positron pairs out of the vacuum by using a quantum computer. “This was one of the most complex experiments ever carried out in an ion-trap quantum computer,” says Blatt, who is excited about the award. “We are still learning about the functioning of quantum simulations; gradually we will be able to apply them to bigger problems in physics.” With their experiment, the physicists built a bridge between two different fields in physics: They used atomic physics experiments to study questions in high-energy physics. “These two approaches complement one another perfectly,” says theoretical physicist Zoller. “We cannot replace the experiments that are done with particle colliders. However, by developing quantum simulators, we may be able to understand these experiments better one day.”

Physics World is the member magazine of the British Institute of Physics. Since 2009 the magazine has recognized the most important breakthroughs of the year in physics. The winning research work has to meet several criteria: It has to show the fundamental importance of research, a significant advance in knowledge, a strong connection between theory and experiment and it has to be of general interest to all physicists.