Twisted Equivariant Matter

By D. Freed, G. Moore. 2012

279 citations recorded by the source corpus.

We show how general principles of symmetry in quantum mechanics lead to twisted notions of a group representation. This framework generalizes both the classical threefold way of real/complex/ quaternionic representations as well as a corresponding tenfold way which has appeared in condensed matter and nuclear physics. We establish a foundation for discussing continuous families of quantum systems. Having done so, topological phases of quantum systems can be defined as deformation classes of continuous families of gapped Hamiltonians. For free particles, there is an additional algebraic structure on the deformation classes leading naturally to notions of twisted equivariant K-theory. In systems with a lattice of translational symmetries, we show that there is a canonical twisting of the equivariant K-theory of the Brillouin torus. We give precise mathematical definitions of two invariants of the topological phases which have played an important role in the study of topological insulators. Twisted equivariant K-theory provides a finer classification of topological insulators than has been previously available.

Subfields: Atomic and Molecular Physics, and Optics, Computational Theory and Mathematics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/5cf27720580ad4342c81c205308af4a5f9d3c64b

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In Atomic and Molecular Physics, and Optics

In Computational Theory and Mathematics

Masahito Ueda

In Statistical and Nonlinear Physics

Citations in the corpus

Symmetry and Topology in Non-Hermitian Physics (2018, background): “where the twist τ 1⁄4 τg;hðkÞ specifies the projective representation for internal degrees of freedom and nonprimitive lattice translations of space group symmetry [233].”