Shortcuts to adiabaticity in non-Hermitian quantum systems without rotating-wave approximation

TL;DR

This paper develops a modified shortcut to adiabaticity (STA) method for non-Hermitian quantum systems that does not rely on the rotating-wave approximation, enabling robust and high-fidelity population transfer.

Contribution

It introduces an exact control function for STA in non-Hermitian systems without RWA and demonstrates its effectiveness through two- and three-level system examples.

Findings

STA is robust for fast population transfer.

Decay has minimal impact on transfer fidelity.

Effective two-level system analysis explains the physics.

Abstract

The technique of shortcuts to adiabaticity (STA) has attracted broad attention due to their possible applications in quantum information processing and quantum control. However, most studies published so far have been only focused on Hermitian systems under the rotating-wave approximation (RWA). In this paper, we propose a modified STA technique to realize population transfer for a non-Hermitian system without RWA. We work out an exact expression for the control function and present examples consisting of two- and three-level systems with decay to show the theory. The results suggest that the STA technique presented here is robust for fast passages. We also find that the decay has small effect on the population transfer in the three-level system. To shed more light on the physics behind this result, we reduce the quantum three-level system to an effective two-level one with large detunings. The STA technique of effective two-level system is studied. Thereby the high-fidelity population transfer can be implemented in non-Hermitian systems by our method, and it works even without RWA.