Dipolar bosons in triangular optical lattices: Quantum phase transitions and anomalous hysteresis

Abstract

We study phase transitions and hysteresis in a system of dipolar bosons loaded into triangular optical lattices at zero temperature. We find that the quantum melting transition from supersolid to superfluid phase is first order, in contrast with the previous report. We also find that due to strong quantum fluctuations the supersolid (or solid)-superfluid transition can exhibit an anomalous hysteretic behavior, in which the curve of density versus chemical potential does not form a standard loop structure. Furthermore, we show that the transition occurs unidirectionally along the anomalous hysteresis curve.

Supersolid States in a Hard-Core Bose–Hubbard Model on a Layered Triangular Lattice

“…Note that this three-leg tube is too thin to quantitatively discuss quantum phase transitions in the system [19]. However, it is known that an effective three-site cluster in a single layer reproduce the reasonable phase diagram.…”

Ground-state phase diagram of the two-dimensional extended Bose-Hubbard model

“…Ultra-cold Bose gases trapped in optical lattice are ideal systems to realize the Bose-Hubbard models [15]. From the intensive theoretical and numerical studies, the existence of supersolid phases has been established in the extended Bose-Hubbard models [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. Most of the supersolids in lattice systems are achieved by doping particles or holes into insulating solid states at commensurate filling factors.…”

Incommensurability Effects on Dipolar Bosons in Optical Lattices

“…These results seem to be consistent with a first-order phase transition. It is worthwhile stressing that a crystal-to-supersolid first-order phase transition has been observed also for ultra-cold soft-core bosons [31,32] and for dipolar bosons in triangular lattices [33] as well.…”