Frustrated superfluids in a non-Abelian flux

TL;DR

This paper investigates novel superfluid states in Rashba spin-orbit coupled bosons on a square lattice, revealing frustration-induced spin-bond correlations, excitation spectra, and critical phenomena with potential cold atom experimental realizations.

Contribution

It introduces a systematic analysis of frustrated superfluids with non-Abelian flux, determining ground states, excitation spectra, and critical exponents, highlighting new quantum phases and transitions.

Findings

Identification of spin-bond correlated superfluids due to non-Abelian flux

Calculation of the Goldstone mode spectrum at the critical point

Different critical exponents on either side of the second-order transition

Abstract

We study possible superfluid states of the Rashba spin-orbit coupled (SOC) spinor bosons with the spin anisotropic interaction $ \lambda $ hopping in a square lattice. The frustrations from the non-abelian flux due to the SOC leads to novel spin-bond correlated superfluids. By using a recently developed systematic "order from quantum disorder" analysis, we not only determine the true quantum ground state, but also evaluate the mass gap in the spin sector at $ \lambda < 1 $, especially compute the the excitation spectrum of the Goldstone mode in the spin sector at $ \lambda=1 $ which would be quadratic without the analysis. The analysis also leads to different critical exponents on the two sides of the 2nd order transition driven by a roton touchdown at $ \lambda=1 $. The intimate analogy at $ \lambda=1 $ with the charge neutral Goldstone mode in the pseudo-spin sector in the Bilayer quantum Hall systems at the total filling factor $ \nu_T=1 $ are stressed. The experimental implications and detections of these novel phenomena in cold atoms loaded on a optical lattice are presented.