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Gapped condensation in higher categories

[Moved Online] Tensor categories and topological quantum field theories March 16, 2020 - March 20, 2020

March 17, 2020 (09:30 AM PDT - 10:30 AM PDT)
Speaker(s): Theo Johnson-Freyd (Perimeter Institute of Theoretical Physics)
  • Karoubi completion

  • TQFTs

  • higher categories

  • gapped phases of matter

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Idempotent (aka Karoubi) completion is used throughout mathematics: for instance, it is a common step when building a Fukaya category. I will explain the n-category generalization of idempotent completion. We call it "condensation completion" because it answers the question of classifying the gapped phases of matter that can be reached from a given one by condensing some of the chemicals in the matter system. From the TFT side, condensation preserves full dualizability. In fact, if one starts with the n-category consisting purely of \bC in degree n, its condensation completion is equivalent both to the n-category of n-dualizable \bC-linear (n-1)-categories and to an n-category of lattice condensed matter systems with commuting projector Hamiltonians. This establishes an equivalence between large families of TFTs and of gapped topological phases. Based on joint work with D. Gaiotto.

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