Chiral spin liquid state of strongly interacting bosons with a moat dispersion: A Monte Carlo simulation

Abstract

We consider a system of strongly interacting bosons in two dimensions with moat band dispersion which supports an infinitely degenerate energy minimum along a closed contour in the Brillouin zone. The system has been theoretically predicted to stabilize a chiral spin liquid (CSL) ground state. In the thermodynamic limit and vanishing densities, n→0, chemical potential, μ, of the uniform CSL state was shown to scale with n as μ∼n2log2n. Here we perform a Monte Carlo simulation to find the parametric window for particle density, n≲k0282π, where k0 is the linear size of the moat (the radius for a circular moat), for which the scaling ∼n2log2n in the equation of state of the homogeneous CSL is preserved. We variationally show that the uniform CSL state is favorable in an interval beyond the obtained scale and present a schematic phase diagram for the system. Our results offer some density estimates for observing the low-density behavior of CSL in time-of-flight experiments with a recently Floquet-engineered moat band system of ultracold atoms in Bracamontes et al. (2022), and for the recent experiments on emergent excitonic topological order in imbalanced electron–hole bilayers.