Niels Bohr Lecture by Andreas Wallraff

Niels Bohr Lecture by Prof. Andreas Wallraff

­­Loophole-free Bell Inequality Violation with Superconducting Circuits*

Andreas Wallraff: Department of Physics, ETH Zurich, Switzerland

Abstract: Superposition, entanglement, and non-locality constitute fundamental features of quantum physics. Remarkably, the fact that quantum physics does not follow the principle of locality can be experimentally demonstrated in Bell tests performed on pairs of spatially separated, entangled quantum systems.

While Bell tests were explored over the past 50 years, only relatively recently experiments free of so-called loopholes succeeded. Here, we demonstrate a loophole-free violation of Bell’s inequality with superconducting circuits [1].

To evaluate a CHSH-type Bell inequality, we deterministically entangle a pair of qubits and perform fast, and high-fidelity measurements along randomly chosen bases on the qubits connected through a cryogenic link spanning 30 meters. Evaluating more than one million experimental trials, we find an average S-value of 2.0747 ± 0.0033, violating Bell’s inequality by more than 22 standard deviations.

Our work demonstrates that non-locality is a viable new resource in quantum information technology realized with superconducting circuits with applications in quantum communication, quantum computing and fundamental physics.


Short Bio: Since January 2012 Andreas Wallraff is a Full Professor for Solid State Physics in the Department of Physics at ETH Zurich.

His research is focused on the experimental investigation of quantum effects in superconducting electronic circuits for performing fundamental quantum optics experiments and for applications in quantum information processing.

His group at ETH Zurich engages in research on micro and nano-electronics, also on hybrid quantum systems combining superconducting electronic circuits with semiconductor quantum dots, making use of fast and sensitive microwave techniques at ultra-low temperatures.

Read more about Andreas Wallraff here >>

Coffee, tea and cake will be served outside Aud. 3 at 15:45