a×b=ca\times b=c in 2+12+1D TQFT

Dec 29, 2020
65 pages
Published in:
  • Quantum 5 (2021) 468
  • Published: Jun 4, 2021
e-Print:
Report number:
  • QMUL-PH-20-37

Citations per year

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Abstract: (Verein zur Foerderung des Open Access Publizierens in den Quantenwissenschaften)
We study the implications of the anyon fusion equation a×b=ca\times b=c on global properties of 2+12+1D topological quantum field theories (TQFTs). Here aa and bb are anyons that fuse together to give a unique anyon, cc. As is well known, when at least one of aa and bb is abelian, such equations describe aspects of the one-form symmetry of the theory. When aa and bb are non-abelian, the most obvious way such fusions arise is when a TQFT can be resolved into a product of TQFTs with trivial mutual braiding, and aa and bb lie in separate factors. More generally, we argue that the appearance of such fusions for non-abelian aa and bb can also be an indication of zero-form symmetries in a TQFT, of what we term "quasi-zero-form symmetries" (as in the case of discrete gauge theories based on the largest Mathieu group, M24M_{24}), or of the existence of non-modular fusion subcategories. We study these ideas in a variety of TQFT settings from (twisted and untwisted) discrete gauge theories to Chern-Simons theories based on continuous gauge groups and related cosets. Along the way, we prove various useful theorems.
Note:
  • 65 pages; 3 figures; 3 appendices; v2: some clarifications in section 3; reference added; v3: brief additional discussion in introduction and references added; v4: summary of results added, typos fixed, additional discussion--to appear in Quantum
  • field theory: topological
  • gauge field theory: discrete
  • group: Mathieu
  • fusion
  • anyon
  • nonabelian
  • Chern-Simons term
  • twist
  • space-time: dimension: 3