Gain without inversion in quantum systems with broken parities

TL;DR

This paper proposes a method to achieve gain without population inversion in quantum systems exhibiting broken parity symmetry, utilizing cyclic transition structures and loop-transitions, with potential implementations in superconducting circuits and chiral molecules.

Contribution

It introduces a novel approach to inversionless gain leveraging broken parity and cyclic transitions, expanding quantum control techniques.

Findings

Demonstrates how broken parity enables cyclic transitions.

Shows how to set control fields for inversionless gain.

Discusses feasible physical implementations.

Abstract

For a quantum system with broken parity symmetry, selection rules can not hold and cyclic transition structures are generated. With these loop-transitions we discuss how to achieve inversionless gain of the probe field by properly setting the control and auxiliary fields. Possible implementations of our generic proposal with specific physical objects with broken parities, e.g., superconducting circuits and chiral molecules, are also discussed.