Phases, many-body entropy measures, and coherence of interacting bosons in optical lattices

R. Roy (1) , A. Gammal , M. C Tsatsos , B. Chatterjee , B. Chakrabarti , Axel U. J. U J Lode

1 Blauvac Obsevatory

Already a few bosons with contact interparticle interactions in small optical lattices feature a variety of quantum phases: superfluid, Mott-insulator, and fermionized Tonks gases can be probed in such systems. To detect these phases-pivotal for both experiment and theory-as well as their many-body properties we analyze several distinct measures for the one-body and many-body Shannon information entropies. We exemplify the connection of these entropies with spatial correlations in the many-body state by contrasting them to the Glauber normalized correlation functions. To obtain the ground state for lattices with commensurate filling (i.e., an integer number of particles per site) for the full range of repulsive interparticle interactions we utilize the multiconfigurational time-dependent Hartree method for bosons (MCTDHB) in order to solve the many-boson Schrödinger equation. We demonstrate that all emergent phases-the superfluid, the Mott insulator, and the fermionized gas can be characterized equivalently by many-body entropy measures and by Glauber's normalized correlation functions. In sharp contrast, single-particle entropy cannot capture these phases.

Mots clés: MCTDH-X; MCTDHB; Entropy; http://ultracold.org; fermionization; correlation functions; Schrödinger equation

Domaines: Gaz Quantiques [cond-mat.quant-gas]; Physique Quantique [quant-ph]; Physique Numérique [physics.comp-ph]; Agrégats Moléculaires et Atomiques [physics.atm-clus]

R. Roy, A. Gammal, M. C Tsatsos, B. Chatterjee, B. Chakrabarti, et al.. Phases, many-body entropy measures, and coherence of interacting bosons in optical lattices. Physical Review A, 2018, 97, pp.043625. ⟨10.1103/PhysRevA.97.043625⟩. ⟨hal-02370274⟩