Preparing Atomic Topological Quantum Matter by Adiabatic Nonunitary Dynamics

TL;DR

This paper proposes an experimentally feasible adiabatic nonunitary protocol to prepare topological quantum states, such as Chern insulators, by coupling and decoupling systems to bypass phase transition constraints.

Contribution

It introduces a novel method for preparing topological states through symmetry breaking and decoupling, applicable to invertible topological phases.

Findings

Protocol successfully prepares Chern insulators in simulations

Coupling to a conjugate system enables topological state formation

Method is generalizable to other invertible topological phases

Abstract

Motivated by the outstanding challenge of realizing low-temperature states of quantum matter in synthetic materials, we propose and study an experimentally feasible protocol for preparing topological states such as Chern insulators. By definition, such (non-symmetry protected) topological phases cannot be attained without going through a phase transition in a closed system, largely preventing their preparation in coherent dynamics. To overcome this fundamental caveat, we propose to couple the target system to a conjugate system, so as to prepare a symmetry protected topological phase in an extended system by intermittently breaking the protecting symmetry. Finally, the decoupled conjugate system is discarded, thus projecting onto the desired topological state in the target system. By construction, this protocol may be immediately generalized to the class of invertible topological phases, characterized by the existence of an inverse topological order. We illustrate our findings with microscopic simulations on an experimentally realistic Chern insulator model of ultracold fermionic atoms in a driven spin-dependent hexagonal optical lattice.