First-Order Phase Transition in Atom-Molecule Quantum Degenerate Mixtures with Coherent Three-Body Recombination
Phys. Rev. Lett. 137, 093401 – Published 24 August, 2026
DOI: https://doi.org/10.1103/llw4-tbnt
Abstract
We map the phase diagram of a two-mode atom-molecule Bose-Einstein condensate with Fano-Feshbach and coherent three-body recombination (cTBR) terms. The standard second-order phase transition observed as the molecular energy is tuned through the Fano-Feshbach resonance is replaced by a first-order transition when cTBR becomes prominent, due to a double-well structure in the free energy landscape. This transition is associated with atom-molecule entanglement, bistability, and molecular metastability. Our results establish cTBR as a powerful knob for quantum state engineering and control of reaction dynamics in ultracold chemistry.
