Photon emission rate from atomic systems in the CSL model

TL;DR

This paper calculates the photon emission rate from atomic systems within the CSL model, showing how emission varies with photon wavelength and atomic structure, and discusses implications for constraining the model's parameters.

Contribution

It provides a generalized calculation of photon emission rates in the CSL model, including effects of atomic structure and noise characteristics, extending previous results.

Findings

Photon emission is suppressed for wavelengths larger than atomic size.

For kilovolt gamma rays, structure factors modify emission rates without suppression.

Results are applicable to non-white noise and non-mass-proportional couplings.

Abstract

We calculate the photon emission rate from a general atomic system in the mass- proportional CSL model. For an isolated charged particle emitting kilovolt gamma rays, our results agree with those obtained by Fu. For a neutral atomic system, photon emission is strongly suppressed for photon wavelengths much larger than the atomic radius. However, for kilovolt gamma rays, Fu's result is modified by a structure factor that is of order unity, giving no rate suppression. Our calculation is readily generalized to the case of non-white noise, noise couplings that are not mass-proportional, and general (non-Gaussian) spatial correlation functions, and corresponding results are given. We briefly discuss the implications of our calculation for upper bounds on the CSL model parameters.