Non-equilibrium quantum magnetism with ultracold Rydberg atoms

Date

Feb 21, 2018

Time

4:30 PM - 5:30 PM

Speaker

Shannon Whitlock

Affiliation

University of Strasbourg

Language

en

Main Topic

Physik

Other Topics

Physik

Description

We experimentally investigate highly tunable quantum systems made of ultracold atoms coupled to highly-excited Rydberg states. Due to their strong and long-range dipolar interactions, these systems provide well controlled models for simulating quantum magnetism and exotic quantum matter, especially in out-of-equilibrium scenarios. I will present two sets of experiments. In the first, we couple two Rydberg states with different orbital angular momenta with a resonant microwave field to realize a dipolar XY spin-1/2 model. Starting from a spin-polarized state we suddenly switch on the external field and monitor the coherent many-body dynamics as it relaxes towards an equilibrium state. By comparing with state-of-the-art theoretical approaches we determine the key processes governing relaxation in this effectively isolated quantum system. In the second, we explore the non-equilibrium regimes of a driven-dissipative Ising-like quantum spin system. Here we find that the rate of spontaneous emission provides a convenient observable which obeys power-law scaling, with exponents that distinguish the different regimes, including classical dynamics, paramagnetic, quantum-critical and a magnetic instability reminiscent of directed percolation. This opens up a new means to study and classify quantum systems out of equilibrium and extends the domain where scale-invariant behaviour can be found in nature.

Last modified: Feb 21, 2018, 8:36:19 AM