Hardcore bosons in a zig-zag optical superlattice

Abstract

We study a system of hard-core bosons at half-filling in a one-dimensional optical superlattice. The bosons are allowed to hop to nearest and next-nearest neighbor sites producing a zig-zag geometry and we obtain the ground state phase diagram as a function of microscopic parameters using the finite-size density matrix renormalization group (FS-DMRG) method. Depending on the sign of the next-nearest neighbor hopping and the strength of the superlattice potential the system exhibits three different phases, namely the bond-order (BO) solid, the superlattice induced Mott insulator (SLMI) and the superfluid (SF) phase. When the signs of both hopping amplitudes are the same (the "unfrustrated" case), the system undergoes a transition from the SF to the SLMI at a non-zero value of the superlattice potential. On the other hand, when the two amplitudes differ in sign (the "frustrated" case), the SF is unstable to switching on a superlattice potential and also exists only up to a finite value of the next nearest neighbor hopping. This part of the phase diagram is dominated by the BO phase which breaks translation symmetry spontaneously even in the absence of the superlattice potential and can thus be characterized by a bond order parameter. The transition from BO to SLMI appears to be first order.

6 pages, 11 figures

References in corpus (7)

• Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
• Coherent control of dressed matter waves
• Chiral Mott insulator with staggered loop currents in the fully frustrated Bose Hubbard model
• Quantum phases of bosons in double-well optical lattices
• Experimental realization of strong effective magnetic fields in optical superlattice potentials
• Phases and phase transitions of frustrated hard-core bosons on a triangular ladder
• Mean field analysis of quantum phase transitions in a periodic optical superlattice

Cited by in corpus (13)

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• Statistics-tuned phases of pseudofermions in one dimension
• One-dimensional s-p superlattice
• Sub- and supercritical defect scattering in Schrödinger chains with higher-order hopping
• Mott insulator phases of non-locally coupled bosons in bilayer optical superlattices
• Solid-state magnetic traps and lattices
• Deconfined quantum criticality of frustrated hard-core dipolar bosons
• Local Hamiltonians for one-dimensional critical models
• One-dimensional superlattices with s-p resonance