### About

### Not Even Wrong: The Book

### Categories

- Book Reviews (43)
- BRST (12)
- Experimental HEP News (138)
- Langlands (18)
- Multiverse Mania (95)
- Not Even Wrong: The Book (26)
- Quantum Mechanics (6)
- Strings 2XXX (13)
- This Week's Hype (71)
- Uncategorized (1,024)

### Recent Comments

- Quick Links 10

jd, David Ben-Zvi, David Roberts, Peter Woit, Bill, Peter Woit [...] - Use the Moment Map, not Noether's Theorem 18

Peter Woit, Peter Woit, Hendrik, João Esteves, Igor Khavkine, Peter Woit [...] - Nature is Fundamentally Conformally Invariant 33

db, ConformallyCyclic, Peter Woit, walkloud, confused, vmarko [...] - Quantum Theory is Representation Theory 43

Peter Morgan, Reader297, Peter Morgan, j.c.j.vandervelde, Reader297, Peter Woit [...] - Grand Unification of Mathematics and Physics 7

David Ben-Zvi, uair01, Urs Schreiber, David Corfield, David Ben-Zvi, David Ben-Zvi [...]

- Quick Links 10
### Archives

### Links

### Mathematics Weblogs

- Alexandre Borovik
- Antwerp Noncommutative Geometry Seminar
- Automorphic Forum
- Cathy O'Neil
- Chromotopy
- Concrete Nonsense
- Danny Calegari
- DZB's blog
- Emmanuel Kowalski
- Jeffrey Morton
- Jesse Johnson
- Johan deJong
- Lieven Le Bruyn
- Michael Hutchings
- Motivic Stuff
- Noncommutative Geometry
- Quomodocumque
- Rigorous Trivialities
- Secret Blogging Seminar
- Terence Tao
- The n-Category Cafe
- Timothy Gowers

### Physics Weblogs

- Alexey Petrov
- Andrew Jaffe
- Angry Physicist
- Capitalist Imperialist Pig
- Chad Orzel
- Charles Day
- Christine Dantas
- Clifford Johnson
- Cormac O’Raifeartaigh
- Cosmic Variance
- Dmitry Podolsky
- Doug Natelson
- EPMG Blog
- Georg von Hippel
- Gordon Watts
- Jacques Distler
- Jennifer Ouellette
- Jim Rohlf
- John Horgan
- John Terning
- Jonathan Shock
- Kyle Cranmer
- Lubos Motl
- Makoto Sakurai
- Martin Perl
- Matt Strassler
- Michael Schmitt
- Philip Gibbs
- Physics World
- Resonaances
- Rhys Davies
- Robert Helling
- Sabine Hossenfelder/Stefan Scherer
- Scott Aaronson
- Sesh Nadathur
- Shaun Hotchkiss
- Shores of the Dirac Sea
- Steve Hsu
- Sujit Datta
- Tommaso Dorigo

### Meta

# Category Archives: BRST

## BRST and Dirac Cohomology

For the last couple years I’ve been working on the idea of using what mathematicians call “Dirac Cohomology” to replace the standard BRST formalism for handling gauge symmetries. So far this is just in a toy model: gauge theory in … Continue reading

Posted in BRST
16 Comments

## Notes on BRST IX: Clifford Algebras and Lie Algebras

Note: I’ve started putting together the material from these postings into a proper document, available here, which will be getting updated as time goes on. I’ll be making changes and additions to the text there, not on the blog postings. … Continue reading

Posted in BRST
4 Comments

## Notes on BRST VIII: Clifford Algebras

Clifford Algebras Clifford algebras are well-known to physicists, in the guise of matrix algebras generated by the -matrices first used in the Dirac equation. They also have a more abstract formulation, which will be the topic of this posting. One … Continue reading

Posted in BRST
6 Comments

## Notes on BRST VII: The Harish-Chandra Homomorphism

The Casimir element discussed in the last posting of this series is a distinguished quadratic element of the center (note, here is a complex semi-simple Lie algebra), but there are others, all of which will act as scalars on irreducible … Continue reading

Posted in BRST
2 Comments

## Notes on BRST VI: Casimir Operators

For the case of , it is well-known from the discussion of angular momentum in any quantum mechanics textbook that irreducible representations can be labeled either by j, the highest weight (here, highest eigenvalue of ), or by , the … Continue reading

Posted in BRST
8 Comments

## BRST News

I should finish writing the next installment of the Notes on BRST series soon, but thought I’d post here about two pieces of BRST-related news, concerning the “B” and the “T”. The “T” in BRST is I.V. Tyutin, whose Lebedev … Continue reading

Posted in BRST
4 Comments

## Notes on BRST V: Highest Weight Theory

In the last posting we discussed the Lie algebra cohomology for a semi-simple Lie algebra. Because the invariants functor is exact here, this tells us nothing about the structure of irreducible representations in this case. In this posting we’ll consider … Continue reading

Posted in BRST
4 Comments

## Notes on BRST IV: Lie Algebra Cohomology for Semi-simple Lie Algebras

In this posting I’ll work out some examples of Lie algebra cohomology, still for finite dimensional Lie algebras and representations. If is a compact, connected Lie group, it can be thought of as a compact manifold, and as such one … Continue reading

Posted in BRST
2 Comments

## Notes on BRST III: Lie Algebra Cohomology

The Invariants Functor The last posting discussed one of the simplest incarnations of BRST cohomology, in a formalism familiar to physicists. This fits into a much more abstract mathematical context, and that’s what we’ll turn to now. Given a Lie … Continue reading

Posted in BRST
6 Comments

## Notes on BRST II: Lie Algebra Cohomology, Physicist’s Version

My initial plan was to have the second part of these notes be about gauge symmetry and the problems physicists have encountered in handling it, but as I started writing it quickly became apparent that explaining this in any detail … Continue reading

Posted in BRST
15 Comments