Nonlinear Spectroscopic Effects in Quantum Gases Induced by Atom-Atom Interactions

TL;DR

This paper explores nonlinear spectroscopic phenomena in ultracold quantum gases caused by atom-atom interactions, focusing on effects like interaction-enhanced double resonance and spectrum instability in two- and three-level atomic systems.

Contribution

It introduces a theoretical analysis of nonlinear spectroscopic effects arising from collisional frequency shifts in ultracold gases, emphasizing simple two- and three-level models.

Findings

Identification of interaction-induced double resonance effects

Analysis of spectrum instability due to population-dependent frequency shifts

Application to two-level and three-level bosonic gases

Abstract

We consider nonlinear spectroscopic effects - interaction-enhanced double resonance and spectrum instability - that appear in ultracold quantum gases owing to collisional frequency shift of atomic transitions and, consequently, due to the dependence of the frequencies on the population of various internal states of the particles. Special emphasis is put to two simplest cases, (a) the gas of two-level atoms and (b) double resonance in a gas of three-level bosons, in which the probe transition frequency remains constant.