Ultracold atom-electron interaction: from two to many-body physics

TL;DR

This paper investigates the transition from few-body to many-body physics using ultralong-range Rydberg molecules, exploring how discrete particle systems evolve into collective phenomena and mean field models.

Contribution

It introduces a study of the crossover from few-body to many-body regimes in ultralong-range Rydberg molecules, highlighting the conditions for mean field approximations.

Findings

Identification of the threshold for many-body behavior

Observation of collective phenomena in Rydberg molecules

Insights into the transition from discrete particles to a Fermi sea

Abstract

The transition from a few-body system to a many-body system can result in new length scales, novel collective phenomena or even in a phase transition. Such a threshold behavior was shown for example in 4He droplets, where 4He turns into a superfluid for a specific number of particles [1]. A particularly interesting question in this context is at which point a few-body theory can be substituted by a mean field model, i. e. where the discrete number of particles can be treated as a continuous quantity. Such a transition from two non-interacting fermionic particles to a Fermi sea was demonstrated recently [2]. In this letter, we study a similar crossover to a many-body regime based on ultralong-range Rydberg molecules [3] forming a model system with binary interactions.