Quantum trajectories for the variational description of closed systems: a case study with Gaussian states

Abstract

It is proposed to improve the quality of a variational description of a closed quantum system by adding ficticious dissipation that reduces the entanglement. The proposal is implemented for a small Bose-Hubbard chain, which shows chaotic behavior and associated fast growth of quantum fluctuations. For appropriately chosen dissipation, good agreement with the truncated Wigner approximation (which is very accurate for the chosen system parameters) is found.