Regular Article

Relaxation of Shannon entropy for trapped interacting bosons with dipolar interactions

¹ Department of Physics, Presidency University, 86/1 College Street, Kolkata 700073, India
² Department of Physics, SRM University Delhi-NCR, Plot No. 39 Rajiv Gandhi education city, Sonipat 131029, India
³ Haifa Research Center for Theoretical Physics and Astrophysics, University of Haifa, Haifa 3498838, Israel
⁴ Department of Mathematics, University of Haifa, Haifa 3498838, Israel
⁵ The Abdus Salam International Center for Theoretical Physics, 34100 Trieste, Italy
⁶ CNR-IOM DEMOCRITOS Simulation Center, Via Bonomea 265, 34136 Trieste, Italy
⁷ Scuola Internazionale di Studi Avanzati (SISSA) and INFN, Sezione di Trieste, Via Bonomea 265, 34136 Trieste, Italy
⁸ Physical Research Laboratory, Navrangpura, Ahmedabad 380009, India

^a e-mail: barnali.physics@presiuniv.ac.in

Received: 22 July 2019
Received in final form: 24 December 2019
Published online: 9 April 2020

Abstract

We study the quantum many-body dynamics and entropy production triggered by an interaction quench of few dipolar bosons in an external harmonic trap. We solve the time-dependent many-body Schrödinger equation by using an in-principle numerically exact many-body method called the multiconfigurational time-dependent Hartree method for bosons (MCTDHB). We study the dynamical measures with high level of accuracy. We monitor the time evolution of the occupation in the natural orbitals and normalized first- and second-order Glauber’s correlation functions. In particular, we focus on the relaxation dynamics of the Shannon entropy. Comparison with the corresponding results for contact interactions is presented. We observe significant effects coming from the presence of the non-local part of the dipolar interaction. The relaxation process is very fast for dipolar bosons with a clear signature of a truly saturated maximum entropy state. We also discuss the connection between the entropy production and the occurrence of correlations and loss of coherence in the system. We identify the long-time relaxed state as a many-body state retaining only diagonal correlations in the first-order correlation function and building up anti-bunching effect in the second-order correlation function.