Publications

2016

Jerger M. et al, 2016
Nature Communications, 7, pp. 12930

Contextuality is one of the most fundamental properties of quantum mechanics, distinguishing it from classical physics without a need for nonlocality or entanglement. It is also a critical resource for exponential speedup in universal surface-code quantum computing. Our result is the first experiment violating a noncontextuality inequality with an indivisible system where entanglement cannot be defined which also addresses all known major loopholes, such as the detection, compatibility and individual-existence loopholes. Violating noncontextuality with superconducting circuits, a leading candidate for implementing surface-code quantum computing, comprises an important conceptual milestone in demonstrating their suitability for quantum technological applications.

2015

Kochetov Bogdan and Fedorov Arkady, 2015
Phys. Rev. B, 92, pp. 224304

The paper theoretically studies effects of the higher non linearities originated from a Josephson junction on the Josephson parametric amplifier (JPA). The results help to understand the gain saturation and reveal some of the effects which were not identified in the previous theoretical studies. Some interesting stipulations on the possible new regimes of the JPA are also deiscussed.

We discuss a similarity between resonant oscillations in two nonlinear systems; namely, a chain 
of coupled Duffing oscillators and a bilayer fish-scale metamaterial. In such systems two

2014

Macha Pascal et al, 2014
Nature Communications, 5, pp. 5146

Implementation of a quantum metamaterial using superconducting qubits

2013

van Loo A. F. et al, 2013
Science, 342, 6165, pp. 1494-1496

We use two superconducting qubits in an open one-dimensional transmission line to study unprecedently strong photon-mediated interactions. Also at arxiv.org.

Lalumière Kevin et al, 2013
Physical Review A, 88, 4

We study the collective effects that emerge in waveguide quantum electrodynamics where several (artificial) atoms are coupled to a one-dimensional superconducting transmission line.

Steffen L. et al, 2013
Nature, 500, 7462, pp. 319-322

We demosntrate the first experimental implementation in solid state.

Berger S. et al, 2013
Physical Review A, 87, 6

We experimentally investigate the effects of noise on the adiabatic and cyclic geometric phase, also termed the Berry phase.

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