Spectral Structure and Many-Body Dynamics of Ultracold Bosons in a Double-Well

• Main Authors: Frank Schäfer, Miguel A. Bastarrachea-Magnani, Axel U. J. Lode, Laurent de Forges de Parny, Andreas Buchleitner
• Format: Article
• Language: English
• Published: MDPI AG 2020-03-01
• Series: Entropy
• Subjects: bosonic systems; ultracold atomic gases; tunneling and josephson effect; bose–einstein condensates in periodic potentials
• Online Access: https://www.mdpi.com/1099-4300/22/4/382

We examine the spectral structure and many-body dynamics of two and three repulsively interacting bosons trapped in a one-dimensional double-well, for variable barrier height, inter-particle interaction strength, and initial conditions. By exact diagonalization of the many-particle Hamiltonian, we specifically explore the dynamical behavior of the particles launched either at the single-particle ground state or saddle-point energy, in a time-independent potential. We complement these results by a characterization of the cross-over from diabatic to quasi-adiabatic evolution under finite-time switching of the potential barrier, via the associated time evolution of a single particle’s von Neumann entropy. This is achieved with the help of the multiconfigurational time-dependent Hartree method for indistinguishable particles (MCTDHmathsizesmall-Xmathsizesmall)—which also allows us to extrapolate our results for increasing particle numbers.