All Questions
Tagged with symmetry-breaking vacuum
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What does it even mean?: "Perturbation theory developed around minima of potential (vacuum) is stable."
(Context: QFT, spontaneous symmetry breaking):
What I have understood from reading the path integral version of the story is that this "vacuum" is actually the classical solution [i.e. which ...
- 11
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Calculating the vacuum in an $O(2)$ spontaneous symmetry breaking
Consider the Lagrangian (we ignore the quantum correction here)
$$\mathcal{L}=-\frac{1}{2} \partial_\mu \phi_1 \partial^\mu \phi_1-\frac{1}{2} \partial_\mu \phi_2 \partial^\mu \phi_2-\frac{\mu^2}{2} \...
- 153
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Is Vacuum Expectation Value equivalent to the sum of Tadpole Diagram in the QFT?
I am recently learning Spontaneously Symmetry Breaking in the QFT. For example let us just focus on the potential $V[\Phi]=a\Phi^2 + b\Phi^4$ where $a<0,b>0$ and denote the vacuum expectation ...
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Relation between RG flow and space of vacua
When studying supersymmetric QFT's, it is very common to compute the moduli space of the theory by solving all F-term equation (derivatives of the superpotential). More precisely, one should also ...
- 1,044
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Why use infinite energy to change a vacuum to the another in usual SSB?
I am reading Strominger's Lecture in the IR triangle, there is a short argument about differences between the usual Higgs case and Large Gauge Symmetry (LGS) one in P38. Strominger says:
In the usual ...
- 347
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Quantum correction to the relation of mass and vacuum expectation value
On Peskin & Schroeder's QFT, page 387, the book gives a general analysis about renormalization and symmetry.
For the example of $\sigma$ mass in the linear sigma model, the classical relation is
$$...
- 1,421
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Quantization of spontaneously broken theory, which is not in the true vacuum
I wonder whether the source $J$ in QFT can make one to quantize the field when the system is in the excursion to the minimum. Precisely, I want to know that following process makes sence.
Suppose, I ...
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Physics of vacuum expectation values in QFT
I have some trouble understanding what is the physical meaning of the vacuum expectation value (VEV) when applied in a QFT context.
Question: What is the physical meaning of a VEV?
I understand that ...
- 1,611
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Are zero-point fluctuations (ZPF) of vacuum Lorentz invariant?
According to the second postulate of Special Relativity the speed of light c must be invariant that consequently leads to the first postulate of Einstein the Lorentz invariance in all inertial frames ...
- 4,170
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Spontaneous Symmetry Breaking and gauge symmetry
As mention in David Tong's Lecture note:
Gauge symmetry is, in many ways, an odd foundation on which to build our best theories of physics. It is not a property of Nature, but rather a property of ...
- 171
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In QCD, Why the order parameter of chiral symmetry takes the form $\langle0 \lvert \bar{\psi}\psi\rvert 0 \rangle$?
A simple question, why the order parameter of QCD chiral symmetry (chiral condensate) take this form:
(or let's say why choose $\bar{\psi}\psi$ to judge there is SSB(spontaneous symmetry breaking) or ...
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1
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118
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Barrier Penetration in Spontaneous Symmetry Breaking
In spontaneous symmetry breaking discussion in Weinberg Chapter 19 section 19.1, he says that the off-diagonal elements between two vacua $$|VAC, +> \pm |VAC->$$ is suppressed by the factor of $$...
- 423
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Why fields carrying spin cannot obtain non-zero vacuum expectation value in a Lorentz invariant theory? [duplicate]
Why fields carrying spin cannot obtain non-zero vacuum expectation value in a Lorentz invariant theory?
- 121
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In the event of a vacuum phase transition, could the universe be left into a state with no fundamental symmetries?
I was having a discussion with a physicist asking him whether there could be any process, compatible with our current knowledge of physics, where the universe would be left without any fundamental ...
- 2,466
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Vacuum Transitions and Lorentz Symmetry Breaking
There are many "bumblebee" models 1, 2 where Lorentz invariance is violated usually resulting from a local vector or tensor field acquiring a nonzero vacuum expectation value
We do not know ...
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