Fragility of the fractional quantum spin Hall effect in quantum gases

Abstract

We consider the effect of contact interaction in a prototypical quantum spin Hall system of pseudo-spin-1/2 particles. A strong effective magnetic field with opposite directions for the two spin states restricts two-dimensional particle motion to the lowest Landau level. While interaction between same-spin particles leads to incompressible correlated states at fractional filling factors as known from the fractional quantum Hall effect, these states are destabilized by interactions between opposite spin particles. Exact results for two particles with opposite spin reveal a quasi-continuous spectrum of extended states with a large density of states at low energy. This has implications for the prospects of realizing the fractional quantum spin Hall effect in electronic or ultra-cold atom systems. Numerical diagonalization is used to extend the two-particle results to many bosonic particles and trapped systems. The interplay between an external trapping potential and spin-dependent interactions is shown to open up new possibilities for engineering exotic correlated many-particle states with ultra-cold atoms.

19 pages, 5 figures, IOP LaTex style, v2: added references & discussion on experimental status/prospects, to appear in New J. Phys. Focus on the Rashba Effect

References in corpus (22)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Dissipationless Quantum Spin Current at Room Temperature
• Realization of the Hofstadter Hamiltonian with ultracold atoms in optical lattices
• High temperature fractional quantum Hall states
• Realizing the Harper Hamiltonian with Laser-Assisted Tunneling in Optical Lattices
• Fractional quantum Hall states at zero magnetic field
• Spin-orbit coupling in quantum gases
• Nearly-flat bands with nontrivial topology
• Spin-Orbit Coupled Spinor Bose-Einstein Condensates
• A Bose-Einstein Condensate in a Uniform Light-induced Vector Potential
• Realistic Time-Reversal Invariant Topological Insulators With Neutral Atoms
• Engineering Time-Reversal Invariant Topological Insulators With Ultra-Cold Atoms
• Spin Hall effects for cold atoms in a light induced gauge potential
• The spin Hall effect in a quantum gas
• Spin-orbit coupling and spin Hall effect for neutral atoms without spin-flips
• Quantum Hall physics in rotating Bose-Einstein condensates
• Ultracold atomic gas in non-Abelian "magnetic" fields: the quantum Hall effect supremacy
• Ultracold atomic gases in non-Abelian gauge potentials: The case of constant Wilson loop
• Non-abelian anyons from degenerate Landau levels of ultracold atoms in artificial gauge potentials
• Quantum simulations of the early universe
• Fractional Spin Hall Effect in Atomic Bose Gases

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• Quantum Hall phase diagram of two-component Bose gases: Intercomponent entanglement and pseudopotentials
• Fractional topological insulator precursors in spin-orbit fermion ladders
• Collective modes of vortex lattices in two-component Bose-Einstein condensates under synthetic gauge fields
• Two-dimensional imbalanced Fermi gas in antiparallel magnetic fields
• Vortex lattices in binary Bose-Einstein condensates: Collective modes, quantum fluctuations, and intercomponent entanglement