Questions tagged [noethers-theorem]
Noether's Theorem relates continuous symmetries (continuous transformations that keep the theory's action invariant) to conservation laws. It finds many applications in modern Physics and generalizes the common notions of conservation of energy, momentum, and angular momentum of Newtonian Mechanics.
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Is there a straightforward simplified proof of energy conservation from time translation symmetry?
Electric charge conservation is easily proven from electric potential gauge symmetry, as follows:
The potential energy of an electric charge is proportional to the electric potential at its location.
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Does quasi-symmetry preserve the solution of the equation of motion?
In some field theory textbooks, such as the CFT Yellow Book (P40), the authors claim that a theory has a certain symmetry, which means that the action of the theory does not change under the symmetry ...
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Analog between Electromagnetism and Gravity
Feynman makes an analogy between EM field and gravity field in his Feynman's Lectures on Gravitation. The vector field representing EM potential would couple to the current source(vector) in the ...
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Deriving the Noether's theorem
I am familiar with how Noether's theorem is derived in some sources/books, the answer in 534699 is particularly clear. However, I'm reading A First Book of Quantum Field Theory by Pal, and although ...
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Noether's theorem by a taste of logic [closed]
I am a mathematician and I asked this question briefly and my question became closed, may be - I don't know - because physicists don't used to apply the method of "proof by contradiction". ...
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Designing a thought experiment on Noether's Theorem [closed]
By Noether's theorem, in classical physics, conservation of total momentum of a system is result of invariance of physical evolution by translation.
So logic says "if" there exists closed ...
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Derivation of the Noether current (Gauss law operator) in anomalous chiral gauge theory
I am reading Fujikawa-Suzuki's Path Integrals and Quantum Anomalies, §6.3. The Lagrangian I am looking at is
\begin{equation}
\mathcal{L}=-\frac{1}{4g^2}\left(\partial_\mu L_\nu^a-\partial_{\nu}L_\mu^...
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Ward identity for special conformal transformation in d dimensions
I am reading CFT from the yellow book ( "Conformal Field Theory" by Francesco, Mathieu, Sénéchal ). In section 4.3.2, they calculate three Ward identities corresponding to (i) translation ...
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Derivation of Noether Current in Condensed Matter Field Theory by Altland and Simons
In Section 1.6 of Condensed Matter Field Theory by Altland and Simons, they prove Noether's theorem. In order to do so, they consider an infinitesimal transformation of the coordinates and the field:
$...
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Proving conservation of supercurrent
I am trying to prove that the supercurrent $J^\mu = \gamma^{\nu \rho} F^A_{\nu \rho} \gamma^\mu \lambda^A $ is conserved in ${\cal N}=1$ SUSY Yang-Mills theory ( basically trying to reproduce equation ...
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Does Noether's theorem apply to a strict on-shell symmetry of the action that holds on every integration region?
I've worked through different proofs of Noether's theorem and read various posts about it on this site. Some important takeaways, among others from this and this post by Qmechanic were
Every off-...
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Building vector Noether current from twistor using Dirac formalism
There was a problem formulated during our lectures to build a Killing vector
$$
\nabla_{(\mu} k_{\nu)} = 0
$$
from equation
$$
{\nabla_{(C}}^{\dot{D}} \varkappa_{A)} = 0.
$$
For me it seems that
$$
k_\...
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Symmetry transformation exact meaning
In whatever text/review I happen to come across (like for example From Noether’s Theorem to Bremsstrahlung: A pedagogical introduction to
Large gauge transformations and Classical soft theorems, ...
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Finding the Noether current
I'm currently reading "QFT for the gifted Amateur by Lancaster and Blundell, and in a lot of the problems I'm a bit unsure of how to do them, an example asked
"Consider a system ...
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How is Noether’s theorem actually applied?
Noether’s theorem roughly states that the existence of a symmetry group for a given system implies a conservation law for that system. All well and good, except that I’m shaky on exactly how you ...
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