All Questions
12
questions
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19
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Symmetry group and dualities
Let's say two quantum models $M_1$ and $M_2$ are dual to each other and let their symmetry groups be $S_1$ and $S_2$ respectively. Is it necessary for $S_1$ to be isomorphic to $S_2$? (I thought so ...
- 366
1
vote
3
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155
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Are dualities symmetries? If so what are their conserved charges?
The dualities described the theories under certain transformations to be equivalent, i.e. $T$-duality described the equivalence between theories with $R$ and $\frac{1}{R}$. However, this looked very ...
- 3,256
1
vote
2
answers
153
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Is it possible to elevate the electric-magnetic duality discrete symmetry to a continuous one?
I'm familiar with Electric-Magnetic duality, where in the absence of source fields one can exchange the $F_{\mu \nu}$ field with the dual field: $\tilde{F}_{\mu \nu}={\epsilon}_{\mu \nu \alpha \beta}
...
- 1,268
2
votes
0
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122
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What's the symmetry group $SU(N)/Z_N$?
I'm trying to understand David Tong's notes, specifically the discussion around page 92 where he's arguing that a different symmetry group may the group of QCD, namely $G'=SU(N)/Z_N$ instead of $G=SU(...
- 43
3
votes
2
answers
559
views
Deriving conserved charges from the equations of motion
It is very well established how to derive conserved charges associated to the symmetries of Lagrangian using the Noether's theorem. Also in the Hamiltonian formulation, we know how to derive the ...
- 980
6
votes
1
answer
284
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What would it mean if symmetries are not fundamental at all?
In this paper 1 written by Joseph Polchinski, he seems to indicate that all symmetries of nature may not be fundamental:
From more theoretical points of view, string theory appears to allow no exact ...
- 2,462
1
vote
2
answers
689
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Energy momentum tensor of EM field written in symmetric form
I'm reading A. Zee's book, Einstein Gravity in a Nutshell. In problem 7 of chapter IV.2, it is said that the energy momentum tensor of the electromagnetic field
\begin{align}
T^{\mu\nu}=\eta_{\lambda\...
- 103
0
votes
1
answer
46
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Understanding parallelisms and duality between temperature and pressure
While I'm not proud of this coming sentence, in physics a lot of different things turn out to be roughly the same thing. For example, the flow of electricity is very much like the flow of water, and ...
- 2,714
4
votes
1
answer
306
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Why T-duality only work when the background has isometries?
I have been studying from some textbooks and papers about the T-dality topic. In particular for the Buscher rules it seems that they claim that in order to have T-duality in certain direction we need ...
- 1,714
5
votes
2
answers
545
views
Definition of Duality (opposed to Symmetry)
I'm learning basic string theory right now and we came across T-duality which was presented as a symmetry of the formula for the mass of a string in the context of compactification. There was a remark ...
- 193
3
votes
1
answer
245
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How to deal with crossing duality and modular invariance in string field theory?
An answer I gave elsewhere.
Some cases to ponder over.
A closed string splits into two closed strings, which then merge again into a single closed string. The overall string worldsheet has the ...
3
votes
2
answers
2k
views
Invariance of Maxwell's Equations under inverting variables - Reference and use
Some months ago, an ArXiv paper mentioned in passing that Maxwell's Equations were invariant under reciprocating the variables, or at least this results in a dual set of Maxwell Equations. (Actually I ...
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