Anomalous Momentum Diffusion in a Dissipative Many-Body System
May 8th, 2019 RAPHAËL BOUGANNE Collège de France, Paris

Decoherence is ubiquitous in quantum physics, from the conceptual foundations to quantum information processing or quantum technologies, where it is a threat that must be countered. While decoherence has been extensively studied for simple, well-isolated systems such as single atoms or ions, much less is known for many-body systems where inter-particle correlations and interactions can drastically alter the dissipative dynamics. Here we report an experimental study of how spontaneous emission destroys the spatial coherence of a gas of strongly interacting bosons in an optical lattice. Instead of the standard momentum diffusion expected for independent atoms, we observe an anomalous sub-diffusive expansion, associated with a universal slowing down in t^{-1/2} of the decoherence dynamics. This algebraic decay reflects the emergence of slowly-relaxing many-body states, akin to sub-radiant states of many excited emitters. These results, supported by theoretical predictions, provide an important benchmark in the understanding of open many-body systems.

Seminar, May 8, 2019, 12:00. ICFO’s Seminar Room

Hosted by Prof. Leticia Tarruell