Floquet Topology Stabilized with Non-Hermitian Driving

TL;DR

This paper introduces a non-Hermitian driving method using external qubits to stabilize Floquet systems indefinitely, even with noise, by removing entropy and enabling localization similar to Anderson localization.

Contribution

It proposes a novel non-Hermitian driving approach that stabilizes Floquet systems through external qubits that carry away entropy and correct noise effects.

Findings

External qubits enable indefinite Floquet system stabilization.

The method effectively removes entropy, acting as a cooling mechanism.

High-frequency entanglement induces strong localization akin to Anderson localization.

Abstract

This study presents a mechanism that enables the stabilization of Floquet systems indefintely; albeit in a manner that allows for noise during each Floquet cycle. This is due to the fact that external qubits are added after each Floquet cycle and these external qubits obtain information about the Floquet system (in this case the Floquet system is the Anomalous Floquet-Anderson Insulator). This information is used to correct the system for noise after which these qubits are removed. The fact that these external qubits are added and then removed after performing operations on the system is what allows for this process to be referred to as non-Hermitian driving. The external qubits effectively act to carry away entropy of the system and therefore allow for the Floquet system to be cooled. In addition, another mechanism is found where the periodic implementation of entanglement for every site of the system at a high frequency during the normal time evolution allows for the system to be highly localized in a manner similar to Anderson localization.