Correlation dynamics of dipolar bosons in 1D triple well optical lattice

Abstract

The concept of spontaneous symmetry breaking and off-diagonal long-range order (ODLRO) are associated with Bose-Einstein condensation. However, as in the system of reduced dimension the effect of quantum fluctuation is dominating, the concept of ODLRO becomes more interesting, especially for the long-range interaction. In the present manuscript, we study the correlation dynamics triggered by lattice depth quench in a system of three dipolar bosons in a 1D triple-well optical lattice from the first principle using the multiconfigurational time-dependent Hartree method for bosons (MCTDHB). Our main motivation is to explore how ODLRO develops and decays with time when the system is brought out-of-equilibrium by a sudden change in the lattice depth. We compare results of dipolar bosons with contact interaction. For forward quench $(V_{f} > V_{i})$, the system exhibits the collapse-revival dynamics in the time evolution of normalized first- and second-order Glauber's correlation function, time evolution of Shannon information entropy both for the contact as well as for the dipolar interaction which is reminiscent of the one observed in Greiner's experiment [Nature, {415}, (2002)]. We define the collapse and revival time ratio as the figure of merit ($τ$) which can uniquely distinguish the timescale of dynamics for dipolar interaction from that of contact interaction. In the reverse quench process $(V_{i} > V_{f})$, for dipolar interaction, the dynamics is complex and the system does not exhibit any definite time scale of evolution, whereas the system with contact interaction exhibits collapse-revival dynamics with a definite time-scale. The long-range repulsive tail in the dipolar interaction inhibits the spreading of correlation across the lattice sites.