Use of quantum quenches to probe the equilibrium current patterns of ultracold atoms in an optical lattice

TL;DR

This paper proposes using quantum quenches to transform equilibrium current patterns in ultracold atoms within optical lattices into measurable density patterns, enabling the detection of complex quantum states.

Contribution

It introduces a novel nonequilibrium quench method to probe and visualize current patterns in ultracold atomic systems with synthetic gauge fields.

Findings

Unidirectional quenches reveal checkerboard and stripe current orders.

Detection of chiral edge currents in quantum Hall states.

Method applicable to both Bose and Fermi gases.

Abstract

Atomic bosons and fermions in an optical lattice can realize a variety of interesting condensed matter states that support equilibrium current patterns in the presence of synthetic magnetic fields or non-abelian gauge fields. As a route to probing such mass currents, we propose a nonequilibrium quantum quench of the Hamiltonian that dynamically converts the current patterns into experimentally measurable real-space density patterns. We illustrate how a specific such "unidirectional" quench of the optical lattice can be used to uncover checkerboard and stripe current orders in lattice Bose superfluids and Fermi gases, as well as chiral edge currents in an integer quantum Hall state.