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Classification of fractional quantum Hall states with spatial symmetries

Strongly Correlated Electrons 2020-12-23 v1 Mesoscale and Nanoscale Physics High Energy Physics - Theory Mathematical Physics math.MP Quantum Physics

Abstract

Fractional quantum Hall (FQH) states are examples of symmetry-enriched topological states (SETs): in addition to the intrinsic topological order, which is robust to symmetry breaking, they possess symmetry-protected topological invariants, such as fractional charge of anyons and fractional Hall conductivity. In this paper we develop a comprehensive theory of symmetry-protected topological invariants for FQH states with spatial symmetries, which applies to Abelian and non-Abelian topological states, by using a recently developed framework of GG-crossed braided tensor categories (G×G\timesBTCs) for SETs. We consider systems with U(1)U(1) charge conservation, magnetic translational, and spatial rotational symmetries, in the continuum and for all 55 orientation-preserving crystalline space groups in two dimensions, allowing arbitrary rational magnetic flux per unit cell, and assuming that symmetries do not permute anyons. In the crystalline setting, applicable to fractional Chern insulators and spin liquids, symmetry fractionalization is fully characterized by a generalization to non-Abelian states of the charge, spin, discrete torsion, and area vectors, which specify fractional charge, angular momentum, linear momentum, and fractionalization of the translation algebra for each anyon. The topological response theory contains 99 terms, which attach charge, linear momentum, and angular momentum to magnetic flux, lattice dislocations, disclinations, corners, and units of area. Using the G×G\timesBTC formalism, we derive the formula relating charge filling to the Hall conductivity and flux per unit cell; in the continuum this relates the filling fraction and the Hall conductivity without assuming Galilean invariance. We provide systematic formulas for topological invariants within the G×G\timesBTC framework; this gives, for example, a new categorical definition of the Hall conductivity.

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Cite

@article{arxiv.2012.11603,
  title  = {Classification of fractional quantum Hall states with spatial symmetries},
  author = {Naren Manjunath and Maissam Barkeshli},
  journal= {arXiv preprint arXiv:2012.11603},
  year   = {2020}
}

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38+46 pages