Vortices and vortex states in Rashba spinorbitcoupled condensates
Abstract
The Rashba spinorbit coupling is equivalent to the finite YangMills flux of a static SU(2) gauge field. It gives rise to the protected edge states in twodimensional topological band insulators, much like magnetic field yields the integer quantum Hall effect. An outstanding question is which collective topological behaviors of interacting particles are made possible by the Rashba spinorbit coupling. Here we address one aspect of this question by exploring the Rashba SU(2) analogs of vortices in superconductors. Using the LandauGinzburg approach and conservation laws, we classify the prominent twodimensional condensates of two and threecomponent spinorbitcoupled bosons, and characterize their vortex excitations. There are two prominent types of condensates that take advantage of the Rashba spinorbit coupling. Their vortices exist in multiple flavors whose number is determined by the spin representation, and interact among themselves through logarithmic or linear potentials as a function of distance. The vortices that interact linearly exhibit confinement and asymptotic freedom similar to quarks in quantum chromodynamics. One of the two condensate types supports small metastable neutral quadruplets of vortices, and their tiles as metastable vortex lattices. Quantum melting of such vortex lattices could give rise to nonAbelian fractional topological insulators, SU(2) analogs of fractional quantum Hall states. The physical systems in which these states could exist are trapped two and threecomponent bosonic ultracold atoms subjected to artificial gauge fields, as well as solidstate quantum wells made either from Kondo insulators such as SmB6 or conventional topological insulators interfaced with conventional superconductors.
 Publication:

Physical Review A
 Pub Date:
 August 2014
 DOI:
 10.1103/PhysRevA.90.023623
 arXiv:
 arXiv:1406.1198
 Bibcode:
 2014PhRvA..90b3623N
 Keywords:

 67.85.Fg;
 67.85.De;
 74.25.Uv;
 Multicomponent condensates;
 spinor condensates;
 Dynamic properties of condensates;
 excitations and superfluid flow;
 Condensed Matter  Quantum Gases
 EPrint:
 20 pages, 8 figures