近日，复旦大学的陈焱&Jie Lou及其研究团队取得一项新进展。经过不懈努力，他们发现一维玻色-费米混合物中具有涌现通量的奇异超流体。相关研究成果已于2024年12月12日在国际知名学术期刊《物理评论A》上发表。

该研究团队在一维玻色-费米哈伯德模型中，当两种粒子存在显著的质量与密度不平衡时，发现了一个手性超流（CSF）相。在该相中，玻色子在链长L下以非零动量±2π/L凝聚。

为了捕捉这一现象的核心物理机制，研究人员研究了一个简化的替代模型，该模型仅涉及单费米子跳跃与由费米子和玻色子组成的复合粒子跳跃之间的竞争。此模型捕捉到了哈伯德模型的低能物理，并展现了一个稳定的手性超流相。

数值研究表明，在手性超流相中，局部的超流序参量沿链连续旋转，表明时间反演对称性被自发破坏。这种对称性的破坏在背景中产生了一个涌现的磁通量，有效地优化了系统的基态能量。研究人员在平均场层面上提供了对这一现象的物理理解。此外，研究人员还探讨了这种相在冷原子实验中实现的可能性。

附：英文原文

Title: Exotic superfluid with emergent flux in a one-dimensional Bose-Fermi mixture

Author: Qi Song, Jie Lou, Yan Chen

Issue&Volume: 2024/12/12

Abstract: We find a chiral superfluid (CSF) phase in a one-dimensional Bose-Fermi Hubbard model with significant mass and density imbalance between the two species. In the CSF phase, bosons condensate at nonzero momentum ±2π/L with chain length L. To capture the essential physics of this phenomenon, we study an alternative simplified model that only features competition between single-fermion hopping and hopping of composite particles composed of a fermion and a boson. This model captures the low-energy physics of the Hubbard model and hosts a robust CSF phase. Our numerical studies show that in the CSF phase, the local superfluid order parameter continuously rotates along the chain, indicating that time-reversal symmetry is spontaneously broken. This symmetry breaking generates an emergent flux in the background, effectively optimizing the system's ground-state energy. We provide a physical understanding at the mean-field level. Furthermore, we have explored the potential realization of this phase in cold-atom experiments.

DOI: 10.1103/PhysRevA.110.063312

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.063312