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arXiv 2001.02208hep-thcond-mat.str-el
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球面上量子霍尔效应的基态波函数与 Atiyah-Singer 指标定理

Ground state wave functions for the quantum Hall effect on a sphere and the Atiyah-Singer index theorem

Brian P. Dolan, Aonghus Hunter-McCabe

AI总结:

本文利用 Dirac 算子和 Wu-Yang 磁单极子研究球面上的量子霍尔效应,证明基态简并受 Atiyah-Singer 指标定理约束,并在复合费米子模型中揭示了偶数磁通涡旋抵消背景场是实现唯一带能隙基态及恢复分数 $ν=\frac{1}{2 k+1}$ 的关键。

摘要:

在球面几何中利用 Dirac 算子研究无相互作用费米子在背景磁场下的量子霍尔效应,该磁场由球心处的 Wu-Yang 磁单极子提供。波函数是非平凡 $U(1)$ 丛的截面,零点能随之消失,且无任何微扰可降低能量。Atiyah-Singer 指标定理约束了基态的简并度。此外,还在复合费米子模型中研究了分数量子霍尔效应。统计规范场的涡旋由与单极场相关的 Dirac 弦提供。仅当涡旋具有偶数个磁通量子并抵消背景场,从而降低复合费米子感受到的有效磁场时,才能获得唯一的基态。系统存在唯一的带能隙基态,且在粒子数较大时恢复分数 $ν=\frac{1}{2 k+1}$。

英文摘要:

The quantum Hall effect is studied in a spherical geometry using the Dirac operator for non-interacting fermions in a background magnetic field, which is supplied by a Wu-Yang magnetic monopole at the centre of the sphere. Wave functions are cross-section of a non-trivial $U(1)$ bundle, the zero point energy then vanishes and no perturbations can lower the energy. The Atiyah-Singer index theorem constrains the degeneracy of the ground state. The fractional quantum Hall effect is also studied in the composite Fermion model. Vortices of the statistical gauge field are supplied by Dirac strings associated with the monopole field. A unique ground state is attained only if the vortices have an even number of flux units and act to counteract the background field, reducing the effective field seen by the composite fermions. There is a unique gapped ground state and, for large particle numbers, fractions $ν=\frac{1}{2 k+1}$ are recovered.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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