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arXiv · 1905.04808

Anomalous momentum diffusion in a dissipative many-body system

Raphaël Bouganne·Manel Bosch Aguilera·Alexis Ghermaoui·Jérôme Beugnon·Fabrice Gerbier
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Abstract

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 $\propto 1/t^{1/2}$ 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.

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Raphaël Bouganne, Manel Bosch Aguilera, Alexis Ghermaoui, Jérôme Beugnon, Fabrice Gerbier. 2019-05-12. Anomalous momentum diffusion in a dissipative many-body system. https://doi.org/10.1038/s41567-019-0678-2

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