Mainz 2017 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 14: Quantum Gases: Bosons II

Q 14.3: Talk

Monday, March 6, 2017, 17:30–17:45, P 204

Non-local correlations in interacting bosonic gases - semiclassical results in non-perturbative regimes — •Benjamin Geiger, Quirin Hummel, and Klaus Richter — Institut für Theoretische Physik, Universität Regensburg, Germany

In order to investigate general properties of interacting bosonic gases we present a formalism to calculate thermodynamic properties and the density of states by means of short-time propagation and compare our analytical predictions against quantum integrable models using Bethe ansatz techniques. As an essential input of our approach, we were able to construct the many-body propagator for a one-dimensional free bosonic gas with delta interactions of variable strength. Using this propagator we can give analytical expressions for the smooth part of the many-body density of states as well as spatial two point correlations for the Lieb-Liniger model. We present explicit analytical results for the high-temperature regime which are non-perturbative in the interaction strength and explain numerical observations by Deuar et. al. [1]. Corrections for lower temperatures can be found systematically. A perturbative approach for arbitrary temperatures using Matsubara theory is presented, which is valid in the weakly interacting regime.

[1] P. Deuar et al., Phys. Rev. A 79, 043619 (2009)