PhD students' seminar: Jan-Philipp BUREIK

PhD students' seminar given by Jan-Philipp BUREIK from the Quantum gases group, on 28 April 2022 at 1.15 in the auditorium of the Institut d'Optique in Palaiseau, on the topic: "Full counting statistics of interacting quantum gases after an expansion."

Abstract: "We study the full counting statistics (FCS) in interacting quantum gases detected atom-by-atom after a free-fall expansion. In the small far-field volumes we consider, the FCS reveals the many- body coherence properties of the gas. We characterise two iconic states of interacting lattice bosons, Mott insulators and Bose superfluids, through their counting statistics and n-body correlations up to n = 6 atoms. Unity-filled Mott insulators exhibit a thermal FCS and perfectly-contrasted amplitudes g(n)(0) ≃ n!. In weakly-interacting Bose superfluids, the FCS measured close to the momentum k = 0 is well described by the Poisson statistics expected for a pure condensate. How- ever, we observe small deviations to a coherent state, g(n)(0) > 1, at high orders of correlations. Furthermore, these deviations become larger as superfluids become more correlated upon increasing the interactions. Finally, we introduce a simple model that incorporates the contribution from the depletion of the condensate, and whose predictions are compatible with our observations over a large range of interaction strengths."