Synthetic gauge fields stabilize a chiral spin liquid phase

TL;DR

This paper explores how synthetic gauge fields can stabilize a chiral spin liquid phase in an SU(N) Hubbard model, revealing phase transitions and potential experimental realizations.

Contribution

It demonstrates that artificial magnetic fields extend the stability of the chiral spin liquid phase across different N and interaction strengths.

Findings

Chiral spin liquid exists for N≥3 with artificial gauge fields.

Adding flux stabilizes the spin liquid as the ground state.

Spin gap increases, suggesting higher temperature stability.

Abstract

We calculate the phase diagram of the SU($N$) Hubbard model describing fermionic alkaline earth atoms in a square optical lattice with on-average one atom per site, using a slave-rotor mean-field approximation. We find that the chiral spin liquid predicted for $N\ge5$ and large interactions passes through a fractionalized state with a spinon Fermi surface as interactions are decreased before transitioning to a weakly interacting metal. We also show that by adding an artificial uniform magnetic field with flux per plaquette $2\pi/N$, the chiral spin liquid becomes the ground state for all $N\ge 3$ at large interactions, persists to weaker interactions, and its spin gap increases, suggesting that the spin liquid physics will persist to higher temperatures. We discuss potential methods to realize the artificial gauge fields and detect the predicted phases.