The symmetry-breaking tag has no wiki summary.
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1answer
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Precise statement of Mermin–Wagner theorem
Roughly speaking, Mermin-Wagner theorem states that continuous symmetries cannot be spontaneously broken at finite temperature in systems with sufficiently short-range interactions in dimensions ...
2
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0answers
53 views
Categorizing solutions to Hierarchy problem
We know that no gauge symmetry can prevent a term $m_\phi^2|\phi|^2$ for a scalar field, and that, given the quadratic loop corrections, the natural scale is $m_\phi \sim M_P$. This is related to the ...
2
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1answer
81 views
How to find the Higgs coupling with a mixing matrix?
It is known that the couplings to the Higgs are proportional to the mass for fermions;
$$g_{hff}=\frac{M_f}{v}$$
where $v$ is the VEV of the Higgs field. I'm trying to figure out why this is true ...
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2answers
90 views
The status of $SU(3)_C$ symmetry in the Standard Model
In the Standard Model of Particle physics the $SU(2)_{EW}$ symmetry and the $SU(2)$ isospin symmetry are broken. What about $SU(3)_C$? Is it broken too?
if YES, what breaks the symmetry?
If NO, what ...
9
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1answer
543 views
Self energy, 1PI, and tadpoles
I'm having a hard time reconciling the following discrepancy:
Recall that in passing to the effective action via a Legendre transformation, we interpret the effective action $\Gamma[\phi_c]$ to be ...
2
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1answer
442 views
Chiral anomaly and decay of the pion
I am told that if all classical symmetries were reflected as quantum symmetries, the decay of the neutral pion $$\pi^0 ~\longrightarrow~ \gamma\gamma$$ would not happen. Why would the conservation of ...
11
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1answer
432 views
Emergent symmetries
As we know, spontaneous symmetry breaking(SSB) is a very important concept in physics. Loosely speaking, zero temprature SSB says that the Hamiltonian of a quantum system has some symmetry, but the ...
0
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3answers
195 views
Ising Ferromagnet: Spontaneous symmetry breaking or not?
In explaining/introducing second-order phase transition using Ising system as an example, it is shown via mean-field theory that there are two magnetized phases below the critical temperature. This ...
5
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1answer
131 views
Early time in the Big Bang
I am not a physicist, so I would really appreciate using a simple language for the explanation of my question. From what I understood at the early Big Bang the four fundamental forces were unified to ...
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1answer
79 views
Symmetry breaking with Lagrangian
I have been studying the spontaneous symmetry braking from Zee (Quantum Field theory ) and found in the page 224, he wrote the lagrangian as
$$\mathcal{L}=
\frac{1}{2}\{
λ
(∂φ)^2 + μ^2φ^ 2\} − ...
5
votes
3answers
221 views
Will Cone standing on its tip, without any other force other than gravity topple?
A cone standing on its tip is considered to be in unstable equilibrium as a slightest force could topple it. So, if the cone is stood on its tip with no other force other than gravity (and the ...
1
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1answer
84 views
Multiple vacua vs. vev's in qft
Take a (possibly supersymmetric) relativistic quantum field theory:
when we construct it, we suppose that there is a unique vacuum state $|0\rangle$ which is Lorentz invariant, vector of some Hilbert ...
4
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1answer
105 views
What kinds of inconsistencies would one get if one starts with Lorentz noninvariant Lagrangian of QFT?
What kinds of inconsistencies would one get if one starts with Lorentz noninvariant Lagrangian of QFT? The question is motivated by this preprint arXiv:1203.0609 by Murayama and Watanabe.
Also, what ...
5
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0answers
53 views
Does the Standard Model plasma develop a spontaneous magnetisation at finite temperature?
Reference: arXiv:1204.3604v1 [hep-ph] Long-range magnetic fields in the ground state of the Standard Model plasma.
Alexey Boyarsky, Oleg Ruchayskiy, Mikhail Shaposhnikov.
The authors of this paper ...
4
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1answer
94 views
Spontaneous symmetry breaking: How can the vacuum be infinitly degenerate?
In classical field theories, it is with no difficulty to imagine a system to have a continuum of ground states, but how can this be in the quantum case?
Suppose a continuous symmetry with charge $Q$ ...
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0answers
54 views
Spontaneous symmetry breaking in the quantum 1D XX model?
The ground states of the quantum 1D Ising and Heisenberg models exhibit spontaneous magnetization. Is this also true for the 1D XX model?
13
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1answer
214 views
Spontaneous breaking of Lorentz invariance in gauge theories
I was browsing through the hep-th arXiv and came across this article:
Spontaneous Lorentz Violation in Gauge Theories. A. P. Balachandran, S. Vaidya. arXiv:1302.3406 [hep-th]. (Submitted on 14 ...
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58 views
Dimensional transmutation in Gross-Neveu vs others
Firstly I don't know how generic is dimensional transmutation and if it has any general model independent definition.
Is dimensional transmutation in Gross-Neveau somehow fundamentally different ...
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0answers
29 views
Residual symmetries of the superposition of two fcc lattices
Fcc lattices are Bravais lattices and so are invariant under a set of discrete translations plus inversions over the 3 axis ($x\rightarrow -x$,$y\rightarrow -y$,$z\rightarrow -z$). When one superposes ...
7
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1answer
92 views
Chiral perturbation theory: what is the Quark Condensate? why expand in $U$ rather than Goldstone fields?
I'm studying Chiral Perturbation Theory (ChPT) from Scherer's manuscript "Introduction to Chiral Perturbation Theory", available at http://arxiv.org/abs/hep-ph/0210398
What I am currently having ...
6
votes
1answer
107 views
What is the meaning of non-compactness in the context of $U(1)$ in gauge theories?
In John Preskill's review of monopoles he states
Nowadays, we have another way of understanding why electric charge is
quantized. Charge is quantized if the electromagnetic U(l)em gauge
group ...
6
votes
1answer
131 views
Where does the hidden supersymmetric sector of the MSSM come from?
At the end of Chapter 14 of the "Supersymmetry Demystified book" from Patrick Labelle it is mentioned that to constrain the number of allowed softly SUSY breaking terms, a shadow or hidden ...
7
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1answer
150 views
Dispersion of ferromagnetic ($E\propto k^2$) and antiferromagnetic ($E\propto k$) spin wave
The dispersion of ferromagnetic spin wave at low energy is $E\propto k^2$, while $E\propto k$ for antiferromagnetic case. Is there a simple/physical argument (such as symmetry) for these results?
...
9
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3answers
414 views
Spontaneous breaking of Lorentz invariance
Is it possible to spontaneously break Lorentz invariance, i.e., have a Lagrangian that respects LI but a vacuum which does not? If it is possible, why isn't there even the slightest hint of the ...
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4answers
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How does Higgs Boson get the rest mass?
Higgs Boson detected at LHC is massive. It has high relativistic mass means it has non-zero rest mass.
Higgs Boson gives other things rest mass. But, how does it get rest mass by itself?
2
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0answers
96 views
Who used the concept of symmetries first?
Who "invented" the concept of symmetries? This article is quite extensive, but it blurs the history with the modern understanding.
http://plato.stanford.edu/entries/symmetry-breaking/
Some of the ...
8
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1answer
45 views
Which is the coupling between the photon and the SU(2)xU(1) gauginos, before symmetry breaking?
The photon field is the non chiral piece of SU(2)xU(1), independently of symmetry breaking or not, isn't it?
But before symmetry breaking, each gauge boson has only a chiral gaugino as ...
3
votes
1answer
248 views
Spontaneous symmetry breaking in SU(5) GUT?
At the end of this video lecture about grand unified theories, Prof. Susskind explains that there should be some kind of an additional Higgs mechanism at work, to break the symmetry between the ...
6
votes
2answers
209 views
Dynamical supersymmetry breaking and Witten index
Witten index, defined as ${\rm Tr}(-1)^F$, makes know if supersymmetry is spontaneously broken or not for a given model. But it is known that supersymmetry can be also broken dynamically and one can ...
3
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2answers
304 views
What is the role of the vacuum expectation value in symmetry breaking and the generation of mass?
Consider a theory of one complex scalar field with the following Lagrangian.
$$
\mathcal{L}=\partial _\mu \phi ^*\partial ^\mu \phi +\mu ^2\phi ^*\phi -\frac{\lambda}{2}(\phi ^*\phi )^2.
$$
The ...
0
votes
0answers
37 views
Taylor-Slavnov Identity in spontaneously broken gauge theories
Where can I find a list of important Taylor-Slavnov identities in Spontaneously broken gauge theories? I am looking for not just the generating functional form, but rather a list of explicit ones ...
3
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0answers
115 views
Higgs stability in Standard Model
I am a little unclear on what ramifications a negative quartic at high energies has on our world at low energies.
(1) First of all, is it that there is a second, isolated minimum that appears at ...
7
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1answer
316 views
Time crystals : fake or revolution?
This article about "crystals of time" just appeared on the PRL website.
Viewpoint: Crystals of Time (http://physics.aps.org/articles/v5/116)
The authors (including famous Frank Wilczek) claim that ...
9
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2answers
859 views
Norton's dome and its equation
Norton's dome is the curve $$h(r) = -\frac{2}{3g} r ^{3/2}.$$ Where $h$ is the height and $r$ is radial arc distance along the dome. The top of the dome is at $h = 0$.
Via Norton's web.
If we put ...
1
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0answers
105 views
Breaking of conformal symmetry
I am wondering something about the breaking of conformal symmetry: I know that it can be broken at the quantum level, anomalously, but I never encountered or heard about a model where it is broken "à ...
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What is spontaneous symmetry breaking in QUANTUM systems?
Most descriptions of spontaneous symmetry breaking, even for spontaneous symmetry breaking in quantum systems, actually only give a classical picture.
According to the classical picture, spontaneous ...
4
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3answers
255 views
How come a photon acts like it has mass in a superconducting field?
I've heard the Higgs mechanism explained as analogous to the reason that a photon acts like it has mass in a superconducting field. However, that's not too helpful if I don't understand the latter. ...
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3answers
223 views
Higgs Boson: The Big Picture
First, please pardon the ignorance behind this question. I know a fair amount of math but almost no physics.
I'm hoping someone can give me a brief "big picture" explanation of how physicists were ...
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1answer
148 views
What if microstates increase proportional to universe volume?
I am probably a delusional crank with a lot of crazy, overly speculative conjectures. If I am not delusional, than at the very least I've been ahead of the curve, the last 40 or so years. I was a ...
2
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2answers
234 views
Effects of a non-Lorentz-invariant vacuum state
I'm here asking about real or though experiments (i.e., physical effects) where, at least in principle, one can see some consequence of a non-Lorentz-invariant vacuum state in an otherwise Poincare ...
7
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2answers
1k views
Why do we need Higgs field to re-explain mass, but not charge?
We already had definition of mass based on gravitational interactions since before Higgs. It's similar to charge which is defined based on electromagnetic interactions of particles.
Why did Higgs ...
3
votes
1answer
152 views
Does spontanous symmetry breaking affect Noethers theorem?
Does spontanous symmetry breaking affect the existence of a conserved charge?
And how does depend on whether we look at a classical or a quantum field theory (e.g. the weak interacting theory)?
...
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2answers
129 views
Do particles gain mass only at energy levels found during the big bang?
I am trying to make sure my understanding is correct.
At energies and temperatures found during the big bang (or at CERN recently), the Higgs mechanism comes into effect. When it does, there is a ...
8
votes
1answer
1k views
Spontaneous Time Reversal Symmetry Breaking?
It is known that you can break P spontaneously--- look at any chiral molecule for an example. Spontaneous T breaking is harder for me to visualize. Is there a well known condensed matter system which ...
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1answer
151 views
Higgs Boson - only little over GCSE physics? [closed]
According to http://www.guardian.co.uk/science/blog/2012/jul/04/higgs-boson-discovered-live-coverage-cern, the reporter says that higgs boson things are little over GCSE physics. So, English learn a ...
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1answer
170 views
What is Supersymmetry (SuSy)?
In particle physics, supersymmetry (often abbreviated SUSY) is a symmetry that relates elementary particles...etc.
what is symmetry breaking?
What is supersymmetry (SUSY)?
What is spontaneous ...
2
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1answer
209 views
Spontaneous symmetry breaking and 't Hooft and Polyakov monopoles
What is spontaneous symmetry breaking from a classical point of view. Could you give some examples, using classical systems.I am studying about the 't Hooft and Polyakov magnetic monopoles solutions, ...
3
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1answer
156 views
What is the code distance in quantum information theory?
What is the code distance in quantum information theory?
Code distance seems to be a very important concept in fault tolerant
quantum computation and topological quantum computation.
1
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1answer
72 views
Can symmetry be restored in high energy scattering?
Suppose you have a field theory with a real scalar field $\phi$ and a potential term of the form $\lambda \phi^4 - \mu \phi^2$ that breaks the symmetry $\phi \to - \phi$ in the ground state. Is this ...
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0answers
68 views
What is the mean field value of a scalar field with spontaneously broken symmetry in a scattering event?
Consider you have a quantum field theory that undergoes spontaneous symmetry breaking at some critical temperature. It doesn't necessarily have to be a continuous symmetry that's broken, I don't think ...
