Impurity dephasing in a Bose-Hubbard model
Authors: Caleffi F.; Capone M.; de Vega I.; Recati A.
Autors Affiliation: International School for Advanced Studies (SISSA), Via Bonomea 265, I-34136 Trieste, Italy; CNR-IOM Democritos, Via Bonomea 265, I-34136 Trieste, Italy; Department of Physics and Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universitat M
Abstract: We study the dynamics of a two-level impurity embedded in a two-dimensional Bose-Hubbard (BH) model at zero temperature from an open quantum system perspective. Results for the decoherence across the whole phase diagram are presented, with a focus on the critical region close to the transition between superfluid and Mott insulator. In particular we show how the decoherence and the deviation from a Markovian behaviour are sensitive to whether the transition is crossed at commensurate or incommensurate densities. The role of the spectrum of the BH environment and its non-Gaussian statistics, beyond the standard independent boson model, is highlighted. Our analysis resorts on a recently developed method (2020 Phys. Rev. Res. 2 033276) – closely related to slave boson approaches – that enables us to capture the correlations across the whole phase diagram. This semi-analytical method provides us with a deep insight into the physics of the spin decoherence in the superfluid and Mott phases as well as close to the phase transitions.
Journal/Review: NEW JOURNAL OF PHYSICS
Volume: 23 (3) Pages from: 033018-1 to: 033018-17
KeyWords: open quantum systems; pure dephasing; cold gases in optical lattices; Bose-Hubbard model; quasiparticles and collective excitationsDOI: 10.1088/1367-2630/abe080