Numerically exact solution of the many emitter -- cavity laser problem: application to the fully quantized spaser emission

TL;DR

This paper presents a numerically exact, nonperturbative quantum solution for many emitter-cavity systems, enabling detailed analysis of spaser emission without common approximations, thus advancing quantum laser theory.

Contribution

It introduces a scalable numerical method for solving the many emitter-cavity problem exactly, applicable to fully quantized models like the spaser, without relying on typical approximations.

Findings

Provides full quantum statistical and correlation data for many emitter-cavity systems.

Demonstrates the method's application to the spaser, confirming its quantum nature.

Scales with the cube of the number of emitters, making it computationally feasible for larger systems.

Abstract

A numerically exact solution to the many emitter -- cavity problem as an open many body system is presented. The solution gives access to the full, nonperturbative density matrix and thus the full quantum statistics and quantum correlations. The numerical effort scales with the third power in the number of emitters. Notably the solution requires none of the common approximations like good/bad cavity limit. As a first application the recently discussed concept of coherent surface plasmon amplification -- spaser -- is addressed: A spaser consists of a plasmonic nanostructure that is driven by a set of quantum emitters. In the context of laser theory it is a laser in the (very) bad cavity limit with an extremely high light matter interaction strength. The method allows us to answer the question of spasing with a fully quantized theory.