Lasing and transport in a quantum dot-resonator circuit

TL;DR

This paper investigates a double quantum dot coupled to a resonator, demonstrating how current measurements can reveal lasing states and resolve small differences in dot properties, with relaxation processes influencing the outcomes.

Contribution

It introduces a method to probe lasing states via transport measurements in a quantum dot-resonator system, highlighting the role of relaxation in enhancing resolution.

Findings

Lasing occurs within a narrow resonance window in the quantum dot-resonator system.

Transport properties are correlated with the lasing state, enabling current-based probing.

Relaxation processes can improve spin state resolution by releasing trapped populations.

Abstract

We study a double quantum dot system coherently coupled to an electromagnetic resonator. A current through the dot system can create a population inversion in the dot levels and, within a narrow resonance window, a lasing state in the resonator. The lasing state correlates with the transport properties. On one hand, this allows probing the lasing state via a current measurement. On the other hand, the resulting narrow current peak allows resolving small differences in the dot properties, e.g., a small difference in the Zeeman splittings of the two dots. For realistic situations relaxation processes have pronounced consequences. Remarkably, they may even enhance the resolution between different spin states by releasing a trapped population in the off-resonant spin channel.