The gauge-theory tag has no wiki summary.
4
votes
1answer
137 views
gauge invariance and Bohm-Aharanov effect
I am confused with the Bohm-Aharanov effect: though quantum mechanics is said to be gauge invariant, the presence of a solenoid imposes a gauge ... I used to think that a phase shift did not change ...
5
votes
2answers
84 views
Torsion and gauge invariant EM kinetic term
Everytime I hear about adding torsion to GR, something struggles me: how do you create a kinetic term for the electromagnetic field that is still gauge-invariant? One of the consequences of torsion is ...
6
votes
2answers
296 views
Wilson/Polyakov loops in Weinberg's QFT books
I wanted to know if the discussion on Wilson loops and Polyakov loops (and their relationship to confinement and asymptotic freedom) is present in the three volumes of Weinberg's QFT books but in some ...
6
votes
1answer
43 views
How does a geodesic equation on an n-manifold deal with singularities?
My general premise is that I want to investigate the transformations between two distinct sets of vertices on n-dimensional manifolds and then find applications to theoretical physics by:
...
4
votes
0answers
315 views
Gauge redundancies and global symmetries
It is often said that local (gauge) transformation is only redundancy of description of spin one massless particles, to make the number degrees of freedom from three to two. It is often said that ...
12
votes
1answer
156 views
What is a “free” non-Abelian Yang-Mill's theory?
I hope this question will not be closed down as something completely trivial!
I did not think about this question till in recent past I came across papers which seemed to write down pretty much ...
22
votes
0answers
404 views
On the Coulomb branch of N=2 supersymmetric gauge theory
The chiral ring of the Coulomb branch of a 4d N=2 supersymmetric gauge theory is given by the Casimirs of the vector multiplet scalars, and they don't have non-trivial relations; the Casimirs are ...
1
vote
0answers
70 views
Reference request: Introductions to current mathematics derived from / related to gauge theories (in physics) [duplicate]
I was searching for introductions to current mathematics derived from / related to gauge theories in physics.
Can someone suggest some good references?
E.g.
Topics in Physical Mathematics by K. ...
5
votes
2answers
112 views
Is the distinction between the Poincaré group and other internal symmetry groups artificial?
For instance, given a theory and a formulation thereof in terms of a principal bundle with a Lie group $G$ as its fiber and spacetime as its base manifold, would a principle bundle with the Poincaré ...
5
votes
1answer
42 views
What does Gribov's last paper tell about coloured states?
In the first days of July 1997, after a long driving effort, crossing all of Europe to come to a meeting in Peñiscola, Vladimir Gribov fell fatally sick and he passed away one month later. His paper ...
10
votes
1answer
132 views
Normalization of the Chern-Simons level in $SO(N)$ gauge theory
In a 3d SU(N) gauge theory with action $\frac{k}{4\pi} \int \mathrm{Tr} (A \wedge dA + \frac{2}{3} A \wedge A \wedge A)$, where the generators are normalized to $\mathrm{Tr}(T^a ...
2
votes
0answers
267 views
Gauge invariance and Feynman path-integrals
Let me look at the Hamiltonian of a charged particle in a plane in a constant magnetic field ($\vec{B}$) pointing upwards - then in usual notation it is,
$$\hat{H} = \frac{1}{2m}\biggl(\hat{p} + ...
6
votes
2answers
175 views
How to prove quantum N=4 Super-Yang-Mills is superconformal?
I'm especially interested in elegant illuminating proofs which don't involve a lot of straightforward technical computations
Also, does a non-perturbative proof exist?
14
votes
3answers
208 views
Which exact solutions of the classical Yang-Mills equations are known?
I'm interested in the pure gauge (no matter fields) case on Minkowski spacetime with simple gauge groups.
It would be nice if someone can find a review article discussing all such solutions
EDIT: I ...
10
votes
1answer
145 views
Chern-Simons theory
In Witten's paper on QFT and the Jones polynomial, he quantizes the Chern-Simons Lagrangian on
$\Sigma\times \mathbb{R}^1$ for two case: (1) $\Sigma$ has no marked points (i.e., no Wilson loops) and ...
13
votes
1answer
95 views
realization of: CFT generating fuction = AdS partition function
An important aspect of the AdS/CFT correspondence is the recipe to compute correlation functions of a boundary operator $\mathcal{O} $ in terms of the supergravity fields in the interior of the ...
12
votes
2answers
152 views
Topological twists of SUSY gauge theory
Consider $N=4$ super-symmetric gauge theory in 4 dimensions with gauge group $G$. As is explained in the beginning of the paper of Kapustin and Witten on geometric Langlands, this
theory has 3 ...
8
votes
2answers
131 views
Is ghost-number a physical reality/observable?
One perspective is to say that one introduced the ghost fields into the Lagrangian to be able to write the gauge transformation determinant as a path-integral. Hence I was tempted to think of them as ...
4
votes
4answers
383 views
References for conceptual issues in Quantum Field Theory
I realize this question is very broad but may be I will still get a helpful answers. References and textbooks for the development of the technical and mathematical aspects of QFT abound. However, I ...
11
votes
2answers
142 views
Gauge invariance for electromagnetic potential observables in test function form
This is a reference request for a relationship in quantum field theory between the electromagnetic potential and the electromagnetic field when they are presented in test function form. $U(1)$ gauge ...
15
votes
0answers
106 views
Systematic approach to deriving equations of collective field theory to any order
The collective field theory (see nLab for a list of main historical references) which came up as a generalization of the Bohm-Pines method in treating plasma oscillations are often used in the study ...
3
votes
1answer
196 views
A loop quantum gravity toy inspired by an Aharonov-Bohm ring
Comparing my question to Give a description of Loop Quantum Gravity your grandmother could understand what I'm looking for here is a toy for a toddler ($\approx$ a pre-QFT graduate student).
I seek ...
9
votes
1answer
30 views
Dual Pairs in Four Dimensions
Following the conversation here, I am wondering if anyone knows of an example of dual pair with 4-dimensional N=1 SUSY which relates a non-Abelian gauge theory on one side to a theory with a ...
15
votes
1answer
131 views
Models of higher Chern-Simons type
It has long been clear that (the action functional of) Chern-Simons theory has various higher analogs and variations of interest. This includes of course traditional higher dimensional Chern-Simons ...
11
votes
1answer
66 views
Are possible gauge fields in a Lagrangian theory always determined by the structure of the charged degrees of freedom?
An elementary example to explain what I mean. Consider introducing a classical point particle with a Lagrangian $L(\mathbf{q} ,\dot{\mathbf{q}}, t)$. The most general gauge transformation is $L ...
41
votes
4answers
3k views
Gauge symmetry is not a symmetry?
I have read before in one of Seiberg's articles something like, that gauge symmetry is not a symmetry but a redundancy in our description, by introducing fake degrees of freedom to facilitate ...
9
votes
1answer
426 views
Discrete gauge theories
I'm trying to understand a particular case of gauge theories, namely discrete spaces on which a group G can act transitively, with a gauge group H which is discrete as well.
From what I've already ...
8
votes
1answer
320 views
argument about fallacy of diff(M) being a gauge group for general relativity
I want to outline a solid argument (or bulletpoints) to show how weak is the idea of diff(M) being the gauge group of general relativity.
basically i have these points that in my view are very solid ...
6
votes
2answers
308 views
Lagrangians combining terms with 1 and 2 derivatives
How are field theory Langrangians treated when some terms have 2 derivatives but others have only 1? Because the number of derivatives in a Lagrangian term is more easily even than odd, the ...
6
votes
5answers
1k views
proof of gauge invariance for quantum 1D ring
This is a question on gauge invariance in quantum mechanics. I do some simple math on a 1D wave-function with periodic boundary conditions, and get that gauge invariance is violated. What am I doing ...
7
votes
4answers
664 views
How many fundamental forces could there be?
We’re told that ‘all forces are gauge forces’. The process seems to start with the Lagrangian corresponding to a particle-type, then the application of a local gauge symmetry leading to the emergence ...
7
votes
2answers
201 views
Is there a meaning to the E,B analogues of other gauge fields?
From the gauge field $A_\mu$ and the QED lagrangian we can derive maxwell's equations in terms of electric and magnetic fields. Are there any situations where similar derivations using the other gauge ...
0
votes
1answer
269 views
What is the spectral energy density of virtual photons around a unit charge at rest?
Given that my previous question, namely "What is the number density of virtual photons around a unit charge?" has no precise answer, here is a more precise wording:
What is the virtual photon ...
2
votes
2answers
289 views
Diff(M) and requirements on GR observables
This question is kind of inspired in this one:
Diff(M) as a gauge group and local observables in theories with gravity
The conundrum i'm trying to understand is how is derived the (quite) ...
-4
votes
3answers
682 views
What is physical in the principle of local gauge invariance? [closed]
Modern theories of interactions in particle physics are gauge ones. I know how the gauge fields are introduced in equations ($D = \partial + A$). I just do not see any physical motivation in it. I am ...
4
votes
1answer
373 views
What is “localisation” of instantons?
I often encountered the term "localization" in the context of instantons, as for example in the work of Nekrasov on extensions of Seiberg-Witten theory to N=1 gauge theories.
Could someone give a ...
2
votes
1answer
483 views
Lattice QCD and string theory
I've heard the claim that some aspects of string theory are used to improve Monte-Carlo simulations of lattice QCD, for example by people working at the LHC.
I know a bit about Monte-Carlo methods in ...
1
vote
1answer
300 views
Single trace partition function
I would be glad if someone can help me understand the argument in appendix B.1 and B.2 (page 76 to 80) of this paper.
The argument in B.1 supposedly helps understand how the authors in that paper ...
9
votes
1answer
725 views
Diff(M) as a gauge group and local observables in theories with gravity
In a gauge theory like QED a gauge transformation transforms one mathematical representation of a physical system to another mathematical representation of the same system, where the two mathematical ...
6
votes
1answer
402 views
Modes of a QFT and irreducible representation of the gauge group
This is in reference to the calculation in section 3.3 starting page 20 of this paper.
I came across an argument which seems to say that the "constraint of Gauss's law" enforces gauge theory on ...
4
votes
2answers
555 views
What's the point of having an einbein in your action?
One often comes across actions written with an extra auxiliary field, with respect to which if you vary the action, you get the equation of motion of the auxiliary field, which when plugged into the ...
13
votes
2answers
2k views
Is there a T-dual of Witten's twistor topological string theory?
In late 2003, Edward Witten released a paper that revived the interest in Roger Penrose's twistors among particle physicists. The scattering amplitudes of gluons in $N=4$ gauge theory in four ...
5
votes
6answers
526 views
Interaction ranges in the Standard Model - Electrodynamics vs QCD
as you might know, the Standard Model of physics can be seen as a $U(1)\times SU(2)\times SU(3)$ gauge theory where each symmetry group accounts for different force fields.
The behaviour for the ...
9
votes
4answers
551 views
Nonlinear optics as gauge theory
the widely used approach to nonlinear optics is a Taylor expansion of the dielectric displacement field $\mathbf{D} = \epsilon_0\cdot\mathbf{E} + \mathbf{P}$ in a Fourier representation of the ...
5
votes
2answers
476 views
Decomposition of a vectorial field in free-curl and free-divergence fields
Is it always possible to do that decomposition? I'm asking it because Helmholtz theorem says a field on $\mathbb{R}^3$ that vanishes at infinity ($r\to \infty$) can be decomposed univocally into a ...
