Parametric tuning of quantum phase transitions in ultracold reactions

TL;DR

This paper explores how generic interactions in ultracold atom-molecule systems can modify quantum phase transitions, leading to new many-body phenomena and affecting reaction yields during Feshbach resonance processes.

Contribution

It demonstrates that interactions fundamentally alter the critical point and phase transition nature, introducing complex many-body effects and new quantum states.

Findings

Interactions change the order of the phase transition.

Correlations induce coherent oscillations between atoms and molecules.

Scaling laws for reaction yield in non-adiabatic regimes are provided.

Abstract

Advances in atomic physics have led to the possibility of a coherent transformation between ultra-cold atoms and molecules including between completely bosonic condensates. Such transformations are enabled by the magneto-association of atoms at a Feshbach resonance which results in a passage through a quantum critical point. In this study, we show that the presence of generic interaction between the constituent atoms and molecules can fundamentally alter the nature of the critical point, change the yield of the reaction and the order of the consequent phase transition. We find that the correlations introduced by this interaction induce nontrivial many-body physics such as coherent oscillations between atoms and molecules, and a selective formation of squeezed molecular quantum states and quantum cat states. We provide analytical and numerical descriptions of these effects, along with scaling laws for the reaction yield in non-adiabatic regimes.