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PERIMETER INSTITUTE RECORDED SEMINAR ARCHIVE

Displaying all lectures given by: Theo Johnson-Freyd


PIRSA:20060018  ( MP4 Medium Res , MP3 , PDF ) Which Format?
On the classification of topological phases
Speaker(s): Theo Johnson-Freyd
Abstract: There is a rich interplay between higher algebra (category theory, algebraic topology) and condensed matter. I will describe recent mathematical results in the classification of gapped topological phases of matter. These results allow powerful techniques from stable homotopy theory and higher catego... read more
Date: 01/06/2020 - 11:00 am
Series: Colloquium

PIRSA:20030111  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Gapped condensation in higher categories
Speaker(s): Theo Johnson-Freyd
Abstract: 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... read more
Date: 17/03/2020 - 12:30 pm

PIRSA:20010023  ( MP4 Medium Res , MP3 , PDF ) Which Format?
A deformation invariant of 1+1D SQFTs
Speaker(s): Theo Johnson-Freyd
Abstract: The elliptic genus is a powerful deformation invariant of 1+1D SQFTs: if it is nonzero, then it protects the SQFT from admitting a deformation to one with spontaneous supersymmetry breaking. I will describe a "secondary" invariant, defined in terms of mock modularity, that goes beyond the elliptic g... read more
Date: 14/01/2020 - 2:30 pm

PIRSA:19120058  ( MP4 Medium Res , MP3 , PDF ) Which Format?
The Cohomology of Groups (Johnson-Freyd/Guo) - Lecture 11
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Date: 13/12/2019 - 1:00 pm

PIRSA:19120001  ( MP4 Medium Res , MP3 , PDF ) Which Format?
The Cohomology of Groups (Johnson-Freyd/Guo) - Lecture 10
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Date: 04/12/2019 - 10:00 am

PIRSA:19110045  ( MP4 Medium Res , MP3 , PDF ) Which Format?
The Cohomology of Groups (Johnson-Freyd/Guo) - Lecture 9
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Date: 27/11/2019 - 10:00 am

PIRSA:19110044  ( MP4 Medium Res , MP3 , PDF ) Which Format?
The Cohomology of Groups (Johnson-Freyd/Guo) - Lecture 8
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Date: 20/11/2019 - 10:00 am

PIRSA:19110043  ( MP4 Medium Res , MP3 , PDF ) Which Format?
The Cohomology of Groups (Johnson-Freyd/Guo) - Lecture 7
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Date: 13/11/2019 - 10:00 am

PIRSA:19110042  ( MP4 Medium Res , MP3 , PDF ) Which Format?
The Cohomology of Groups (Johnson-Freyd/Guo) - Lecture 6
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Date: 06/11/2019 - 10:00 am

PIRSA:19100049  ( MP4 Medium Res , MP3 , PDF ) Which Format?
The Cohomology of Groups (Johnson-Freyd/Guo) - Lecture 5
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Date: 30/10/2019 - 10:00 am

PIRSA:19100048  ( MP4 Medium Res , MP3 , PDF ) Which Format?
The Cohomology of Groups (Johnson-Freyd/Guo) - Lecture 4
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Date: 23/10/2019 - 10:00 am

PIRSA:19100047  ( MP4 Medium Res , MP3 , PDF ) Which Format?
The Cohomology of Groups (Johnson-Freyd/Guo) - Lecture 3
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Date: 16/10/2019 - 10:00 am

PIRSA:19100046  ( MP4 Medium Res , MP3 , PDF ) Which Format?
The Cohomology of Groups (Johnson-Freyd/Guo) - Lecture 2
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Date: 09/10/2019 - 10:00 am

PIRSA:19100045  ( MP4 Medium Res , MP3 , PDF ) Which Format?
The Cohomology of Groups (Johnson-Freyd/Guo) - Lecture 1
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Date: 02/10/2019 - 10:00 am

PIRSA:19060036  ( MP4 Medium Res , MP3 , PDF ) Which Format?
TA Session: 0d QFT and Feynman diagrams
Speaker(s): Theo Johnson-Freyd
Abstract:
Date: 17/06/2019 - 4:00 pm

PIRSA:18120023  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Koszul Duality Seminar
Speaker(s): Theo Johnson-Freyd
Abstract:

Being held in the Skyroom.

Date: 12/12/2018 - 2:30 pm

PIRSA:18080042  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Welcome and Opening Remarks
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Date: 13/08/2018 - 9:00 am

PIRSA:18010092  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Higher algebraic closures and phases of matter
Speaker(s): Theo Johnson-Freyd
Abstract:
Date: 15/01/2018 - 2:00 pm

PIRSA:16090051  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Moonshine, topological modular forms, and 576 fermions.
Speaker(s): Theo Johnson-Freyd
Abstract:

I will report on progress understanding the 576-fold periodicity in TMF in terms of conformal field theoretic constructions.  Sporadic finite groups and their cohomology will play a role.

Date: 22/09/2016 - 1:30 pm
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