Next seminar : Séminaire du LPTMS: Antoine Browaeys

Tuesday, December 12 2017 at 11:00:00

Many-body physics with arrays of individual Rydberg atoms

Antoine Browaeys (Laboratoire Charles Fabry, Institut d'Optique)

This talk will present our effort to control the interaction between cold Rydberg atoms in order to implement spin Hamiltonians that may be useful for quantum simulation of condensed matter problems. In our experiment, we trap individual atoms in two-dimensional arrays of optical tweezers separated by few micrometers and excite them to Rydberg states using lasers. We will present our demonstration of the coherent energy exchange between two Rydberg atoms resulting from their dipole-dipole interaction, and the implementation of the quantum Ising model in a system of 50 atoms with van der Waals Rydberg interaction. This demonstrates a new platform for quantum simulation using neutral atoms complementary to the ones based on ions, magnetic atoms or dipolar molecules.

Last Highlight : Hall voltage drives pulsing counter-currents of the sliding charge density wave and of quantized normal carriers at self-filled Landau levels

The journal Nature Quantum Materials has just published [1] an article presented by an international team from the Neel Institute in Grenoble – France, LPTMS-CNRS and the University Paris-Sud Saclay at Orsay – France and the Institute for Radioengenering and Electronics in Moscow – Russia. The article is entitled “Hall voltage drives pulsing counter-currents of the sliding charge density wave and of quantized normal carriers at self-filled Landau levels”.
The presented studies integrate such different phenomena as the quantum Hall state for normal electrons, collective effects for electrons condensed to the sliding charge density wave state, conversion among the two kinds of electronic states by a coherent high frequency sequence of dynamical topological events – instantaneous phase-slip centers. The earlier unknown regimes include: self-tuning to the integer quantum Hall state by means of redistribution of the electronic density under the Lorentz force; quantum Hall state under the applied current and the resulting pulsing non-stationary regime; depinning and sliding of the charge density wave under the Hall voltage; surprising regime of compensated countercurrents from the normal and collective subsystems. All that was achieved thanks to the original design of junction structures by means of the focused ion beam technology and by the numerical modeling of spatio-temporal evolution based on the newly derived equations.

[1] Serguei Brazovskii, Andrey Orlov, Alexander Sinchenko, Pierre Monceau, and Yuri Latyshev, 
NPJ Quantum Materials 2, 61 (2017)



Figure. Evolution with periodic phase slips as spatiotemporal vortices: the 3D plot of the CDW phase ϕ(t,x)/π on top of the density plot showing the vorticity (left); the CDW amplitude A(t,x) with nodes at the vortex centers (right).

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