Mott transition in a cavity-boson system: A quantitative comparison between theory and experiment

Abstract

The competition between short-range and cavity-mediated infinite-range interactions in a cavity-boson system leads to the existence of a superfluid phase and a Mott-insulator phase within the self-organized regime. In this work, we quantitatively compare the steady-state phase boundaries of this transition measured in experiments and simulated using the Multiconfigurational Time-Dependent Hartree Method for Indistinguishable Particles. To make the problem computationally feasible, we represent the full system by the exact many-body wave function of a two-dimensional four-well potential. We argue that the validity of this representation comes from the nature of both the cavity-atomic system and the Bose-Hubbard physics. Additionally, we show that the chosen representation only induces small systematic errors, and that the experimentally measured and theoretically predicted phase boundaries agree reasonably well. We thus demonstrate a new approach for the quantitative numerical modeling for the physics of the superfluid--Mott-insulator phase boundary.

Dynamics of order-disorder and complexity for interacting bosons in optical lattice

“…The efficiency of MCTDHB is to make the sampled Hilbert space dynamically follow the time evolution of the many-body system. MCTDHB has been widely used in different theoretical calculations [36,[51][52][53] and results are very close to experimental predictions [54,55]. For M → ∞ limit, as the set of permanents | n; t span the complete Hilbert space, the expansion is exact.…”

Out of equilibrium many-body expansion dynamics of strongly interacting bosons

“…It is to be noted that both the expansion coefficients {C n(t )} as well as orbitals {φ i (x, t)} M i=1 that build up the permanents |n; t〉 are time dependent and fully variationally optimised quantities. Comparing to time-independent basis, as the permanents are time-dependent, a given degree of accuracy is reached with much shorter expansion [34,35]. We also emphasise that MCTDHB is more accurate than exact diagonalization which uses the finite basis and are not optimised.…”