# Decoherence in excited atoms by low-energy scattering

## TL;DR

This paper introduces a novel decoherence mechanism in excited atoms caused by thermal particle scattering, which could be useful for detecting weakly-interacting particles like dark matter.

## Contribution

It presents a new decoherence mechanism based on nuclear displacement from scattering, with potential applications in dark matter detection.

## Key findings

- Decoherence increases with atomic excitation, especially in Rydberg atoms.
- Order of decoherence estimated for photons and massive particles.
- Potential for detecting weakly-interacting particles like dark matter.

## Abstract

We describe a new mechanism of decoherence in excited atoms as a result of thermal particles scattering by the atomic nucleus. It is based on the idea that a single scattering will produce a sudden displacement of the nucleus, which will be perceived by the electron in the atom as an instant shift in the electrostatic potential. This will leave the atom's wave-function partially projected into lower-energy states which will lead to decoherence of the atomic state. The decoherence is calculated to increase with the excitation of the atom, making observation of the effect easier in Rydberg atoms. We estimate the order of the decoherence for photons and massive particles scattering, analyzing several commonly presented scenarios. Our scheme can be applied to the detection of weakly-interacting particles, like those which may be the constituents of Dark Matter, which interaction was calculated to have a more prominent effect that the background radiation.