# Quantum Physics

## Quantum circuits

Our research group explores the physics of information in quantum devices, which we design, realize and measure. These objects can be viewed as quantum machines processing information. In contrast with ordinary devices, in which quantum mechanics enters only at the level of individual electrons, the degrees of freedom of these machines at the signal level behave according to the laws of quantum mechanics.

Topics of our current interest include amplification of quantum signals, manifestations of zero point fluctuations in circuits, quantum feedback and trajectory, thermodynamics of quantum information, experimental tests of deviations to quantum theory, microwave quantum optics and quantum measurement. For more information, follow this link.

## Superfluid turbulence

Julien Salort, Laurent Chevillard, Francesca Chilla

We use superfluid Helium to explore the turbulence in quantum fluids. One motivation is to investigate how turbulence and non-linear mechanisms interplay with small scale mechanisms. The dynamics of superfluid turbulence is strongly determined by the physics ofquantum vortices, and the dissipation mechanism at small scale are very different from classical fluids. However, statistical features and large scale behavior of classical fluids are mostly recovered when the turbulence is sufficiently developed. We participate in international collaborations which aim at setting up highly turbulent quantum flows, such as the SHREK experiment in Grenoble, and we develop our own experimental apparatus in Lyon, focused on intermediate cases. A large effort is devoted to instrumentation, based on dedicated micro-sensors, used by several collaborators.