# Rydberg impurity in a Fermi gas: Quantum statistics and rotational blockade

## TL;DR

This paper investigates how quantum statistics influence Rydberg impurity interactions in a Fermi gas, revealing effects like molecular state suppression and spectral narrowing that reflect the gas's quantum properties.

## Contribution

It demonstrates, using a functional determinant approach, the impact of Fermi statistics and fluctuations on molecular formation and spectral features in a Rydberg-perturbed Fermi gas.

## Key findings

- Fermi statistics suppress molecular formation in certain shell structures.
- Spectral narrowing occurs at high gas densities.
- Spectral features can probe the thermodynamic properties of the quantum gas.

## Abstract

We consider the quench of an atomic impurity via a single Rydberg excitation in a degenerate Fermi gas. The Rydberg interaction with the background gas particles induces an ultralong-range potential that binds particles to form dimers, trimers, tetramers, etc. Such oligomeric molecules were recently observed in atomic Bose-Einstein condensates. In this work, we demonstrate with a functional determinant approach that quantum statistics and fluctuations have observable spectral consequences. We show that the occupation of molecular states is predicated on the Fermi statistics, which suppresses molecular formation in an emergent molecular shell structure. At large gas densities this leads to spectral narrowing, which can serve as a probe of the quantum gas thermodynamic properties.