近日，美国科罗拉多矿业学院的Laith H. Haddad及其研究团队取得一项新进展。经过不懈努力，他们揭示（1 + 1）维中成对狄拉克费米子的自旋-电荷分离。相关研究成果已于2024年11月14日在国际知名学术期刊《高能物理杂志》上发表。

该研究团队研究了有限密度下的狄拉克费米子与一个假设遵循具有四次自斥的标量场理论的复配对场的耦合。这一工作主要发展了相关数学理论，用以阐明此类系统中费米子激发的传播，这些激发表现为独立的自旋（提升）和电荷（费米子数）自由度。一个必要的条件是配对场中存在破缺的U(1)对称性，以及其密度和相位的解耦。

在费米子部分，这些因素导致了一种自旋依赖的规范耦合的出现，该耦合将真空中的自旋和电荷结合成基本费米子，同时在配对场中存在有限凝聚时，驱动未结合的自旋和电荷的增殖。值得注意的是，自旋-电荷分离的开始以PT对称性的破缺和洛伦兹变换下自旋分量的解耦为标志。这项研究以两个定理作为结论，这两个定理确定了此类系统中自旋-电荷分离的普遍特征。

附：英文原文

Title: Spin-charge separation for paired Dirac fermions in (1 + 1) dimensions

Author: Haddad, Laith H.

Issue&Volume: 2024-11-14

Abstract: We study Dirac fermions at finite density coupled to a complex pairing field assumed to obey scalar field theory with quartic self-repulsion. The bulk of our work develops the mathematics that elucidates the propagation of fermionic excitations in such systems as independent spin (boosts) and charge (fermion number) degrees of freedom. A necessary ingredient is the presence of broken U(1) symmetry in the pairing field and decoupling of its density and phase. In the fermion sector, these elements give rise to an emergent spin-dependent gauge coupling which binds in-vacuum spin and charge into elementary fermions, while driving proliferation of unbound spin and charge for finite condensation in the pairing field. Notably, the onset of spin-charge separation is signaled by PT-symmetry breaking and decoupling of spin components under Lorentz transformations. Our investigation concludes with two theorems that identify generic features of spin-charge separation in such systems.

DOI: 10.1007/JHEP11(2024)088

Source: https://link.springer.com/article/10.1007/JHEP11(2024)088