First-order decomposition of thermal light in terms of a statistical mixture of pulses

TL;DR

This paper constructs mixtures of coherent pulses that replicate the first-order correlation function of thermal light, offering an alternative description relevant for broadband light-matter interaction studies.

Contribution

It introduces a novel method to represent thermal light as a mixture of coherent pulses with specific spectral properties, enhancing understanding of light-matter interactions.

Findings

Mixtures of pulses with Gaussian lineshape replicate thermal light correlations.

The approach models thermal light using multi-frequency coherent states.

Results are relevant for time-resolved measurements of natural thermal light.

Abstract

We investigate the connection between thermal light and coherent pulses, constructing mixtures of single pulses that yield the same first-order, equal-space-point correlation function as thermal light. We present mixtures involving (i) pulses with a Gaussian lineshape and narrow bandwidths, and (ii) pulses with a coherence time that matches that of thermal light. We characterize the properties of the mixtures and pulses. Our results introduce an alternative description of thermal light in terms of multi-frequency coherent states, valid for the description of broadband linear light-matter interactions. We anticipate our results will be relevant to time-resolved measurements that aim to probe the dynamics of systems as if they were excited by natural thermal light.