近日，德国马克斯普朗克研究所教授Xin-Yu Luo及其研究团队发现了从极化子凝聚物到杂核分子简并费米气体的转变。2023年2月13日出版的《自然—物理学》杂志发表了这项成果。

研究人员报告了在密度匹配的简并玻色-费米混合物中从极化子相到分子相的相变一致的观测结果。表示跃迁序参量的凝析态分数被相互作用耗尽，强相关性的建立导致分子费米气体的出现。潜在的量子相变的特征代表了一种新的现象，补充了在费米系统中观察到的聚合玻色-爱因斯坦凝聚/巴丁-库珀-施里弗交叉。通过驱动系统完成过渡，课题组产生了钠钾分子的样品，在量子简并体系中表现出大分子框架偶极矩。

据了解，量子统计的相互作用和相互作用的原子玻色-费米混合物导致相图明显不同于纯费米子或玻色子系统。然而，当玻色子因快速的种间损耗而冷凝时，研究这一相图仍然具有挑战性。

附：英文原文

Title: Transition from a polaronic condensate to a degenerate Fermi gas of heteronuclear molecules

Author: Duda, Marcel, Chen, Xing-Yan, Schindewolf, Andreas, Bause, Roman, von Milczewski, Jonas, Schmidt, Richard, Bloch, Immanuel, Luo, Xin-Yu

Issue&Volume: 2023-02-13

Abstract: The interplay of quantum statistics and interactions in atomic Bose–Fermi mixtures leads to a phase diagram markedly different from pure fermionic or bosonic systems. However, investigating this phase diagram remains challenging when bosons condense due to the resulting fast interspecies loss. Here we report observations consistent with a phase transition from a polaronic to a molecular phase in a density-matched degenerate Bose–Fermi mixture. The condensate fraction, representing the order parameter of the transition, is depleted by interactions, and the build-up of strong correlations results in the emergence of a molecular Fermi gas. The features of the underlying quantum phase transition represent a new phenomenon complementary to the paradigmatic Bose–Einstein condensate/Bardeen–Cooper–Schrieffer crossover observed in Fermi systems. By driving the system through the transition, we produce a sample of sodium–potassium molecules exhibiting a large molecule-frame dipole moment in the quantum-degenerate regime.

DOI: 10.1038/s41567-023-01948-1

Source: https://www.nature.com/articles/s41567-023-01948-1