Reply to the Comment on "Thermal, quantum antibunching and lasing thresholds from single emitters to macroscopic devices"

TL;DR

This paper defends the validity of a laser model against a comment claiming an omission invalidates the threshold, demonstrating the model's correctness and broad applicability in laser physics.

Contribution

It clarifies the correct omission of a collective effect term and confirms the laser threshold remains valid, reinforcing the original model's accuracy and significance.

Findings

The omitted term represents unobservable collective effects.

Including the term does not eliminate the laser threshold.

The original model is validated and widely applicable.

Abstract

We deconstruct and address a comment to Carroll et al. [Phys Rev Lett 126, 063902 (2021)] (PRL) that has been posted on arXiv appearing as two versions [arXiv:2106.15242v1] and [arXiv:2106.15242v2]. This comment claimed that a term in the model presented in the PRL had been incorrectly omitted and that, hence, the laser threshold predicted by the model in the PRL is unattainable. We show that the term in question was correctly neglected because it represents collective effects that are not observable in the devices modelled in the PRL. Moreover, even if this term were to be included, the laser threshold would still be present, contrary to what was claimed in the comment. We conclude that the model presented in PRL is correct and that its results are innovative and of wide application in laser physics and quantum optics.