Volume 25, issue 3 (2021)

Download this article
Download this article For screen
For printing
Recent Issues

Volume 28
Issue 7, 3001–3510
Issue 6, 2483–2999
Issue 5, 1995–2482
Issue 4, 1501–1993
Issue 3, 1005–1499
Issue 2, 497–1003
Issue 1, 1–496

Volume 27, 9 issues

Volume 26, 8 issues

Volume 25, 7 issues

Volume 24, 7 issues

Volume 23, 7 issues

Volume 22, 7 issues

Volume 21, 6 issues

Volume 20, 6 issues

Volume 19, 6 issues

Volume 18, 5 issues

Volume 17, 5 issues

Volume 16, 4 issues

Volume 15, 4 issues

Volume 14, 5 issues

Volume 13, 5 issues

Volume 12, 5 issues

Volume 11, 4 issues

Volume 10, 4 issues

Volume 9, 4 issues

Volume 8, 3 issues

Volume 7, 2 issues

Volume 6, 2 issues

Volume 5, 2 issues

Volume 4, 1 issue

Volume 3, 1 issue

Volume 2, 1 issue

Volume 1, 1 issue

The Journal
About the Journal
Editorial Board
Editorial Procedure
Subscriptions
 
Submission Guidelines
Submission Page
Policies for Authors
Ethics Statement
 
ISSN 1364-0380 (online)
ISSN 1465-3060 (print)
Author Index
To Appear
 
Other MSP Journals
Reflection positivity and invertible topological phases

Daniel S Freed and Michael J Hopkins

Geometry & Topology 25 (2021) 1165–1330
Abstract

We implement an extended version of reflection positivity (Wick-rotated unitarity) for invertible topological quantum field theories and compute the abelian group of deformation classes using stable homotopy theory. We apply these field theory considerations to lattice systems, assuming the existence and validity of low-energy effective field theory approximations, and thereby produce a general formula for the group of symmetry protected topological (SPT) phases in terms of Thom’s bordism spectra; the only input is the dimension and symmetry type. We provide computations for fermionic systems in physically relevant dimensions. Other topics include symmetry in quantum field theories, a relativistic 10–fold way, the homotopy theory of relativistic free fermions, and a topological spin-statistics theorem.

Keywords
topological phases, invertible field theory, reflection positivity, symmetry protected topological phases, free fermions, topological field theory
Mathematical Subject Classification 2010
Primary: 55N22, 57R90, 81T45, 81T50, 82B99
References
Publication
Received: 12 July 2016
Revised: 3 October 2019
Accepted: 29 October 2019
Published: 20 May 2021
Proposed: Peter Teichner
Seconded: Ralph Cohen, Ulrike Tillmann
Authors
Daniel S Freed
Department of Mathematics
University of Texas
Austin, TX
United States
Michael J Hopkins
Department of Mathematics
Harvard University
Cambridge, MA
United States