Dipolar interaction driven phase transitions in a one-dimensional optical lattice with a synthetic dimension
1 International Center for Quantum Materials, School of Physics, Peking University - Beijing 100871, PRC
2 Collaborative Innovation Center of Quantum Matter - Beijing 100871, PRC
Received: 17 November 2016
Accepted: 5 April 2017
Extensive research interest has been attracted by the fact that recent experiments in cold atoms simulate the chiral edge states of (1 + 1)-dimensional quantum Hall systems with laser-assisted transitions between different atomic nuclear spin states in a one-dimensional optical lattice. Within such an optical lattice, we study the phase diagrams of filling hard-core fermions and hard-core bosons with internal spin states in the presence of dipole-dipolar interactions. Our results show that the interaction drives the fermionic (bosonic) systems from the normal (superfluid) phase into the fractional topological phase with possible crystalline orderings. The topological nature of the latter phase is identified by the numerical evaluation of the many-body Chern number. Remarkably, we find that a considerable spectrum gap stabilizes the fractional topological phase with a moderate interaction strength, while, for the normal/superfluid phase, the Thouless charge pumping fluctuates strongly for small spin systems but approaches its universal value 1/3 for fermionic and 1/2 for bosonic systems with large spins.
PACS: 33.80.Be – Level crossing and optical pumping / 05.30.Rt – Quantum phase transitions / 73.43.-f – Quantum Hall effects
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