Light scattering and dissipative dynamics of many fermionic atoms in an optical lattice

TL;DR

This paper models the dissipative dynamics of fermionic atoms in optical lattices under light scattering, revealing the robustness of magnetic correlations in Mott insulators and superradiant effects in bound states, with implications for quantum simulation.

Contribution

It derives a microscopic master equation for many-fermion systems in optical lattices under incoherent light scattering, analyzing the robustness of correlations and superradiance effects.

Findings

Magnetic correlations in Mott insulators are robust against decoherence.

Superradiant decay affects bound dimer correlations under typical parameters.

The formalism can be extended to SU(N) symmetric states.

Abstract

We investigate the many-body dissipative dynamics of fermionic atoms in an optical lattice in the presence of incoherent light scattering. Deriving and solving a master equation to describe this process microscopically for many particles, we observe contrasting behaviour in terms of the robustness against this type of heating for different many-body states. In particular, we find that the magnetic correlations exhibited by a two-component gas in the Mott insulating phase should be particularly robust against decoherence from light scattering, because the decoherence in the lowest band is suppressed by a larger factor than the timescales for effective superexchange interactions that drive coherent dynamics. Furthermore, the derived formalism naturally generalizes to analogous states with SU(N) symmetry. In contrast, for typical atomic and laser parameters, two-particle correlation functions describing bound dimers for strong attractive interactions exhibit superradiant effects due to the indistinguishability of off-resonant photons scattered by atoms in different internal states. This leads to rapid decay of correlations describing off-diagonal long-range order for these states. Our predictions should be directly measurable in ongoing experiments, providing a basis for characterising and controlling heating processes in quantum simulation with fermions.