What is Symmetry breaking: Definition and 119 Discussions
In physics, symmetry breaking is a phenomenon in which (infinitesimally) small fluctuations acting on a system crossing a critical point decide the system's fate, by determining which branch of a bifurcation is taken. To an outside observer unaware of the fluctuations (or "noise"), the choice will appear arbitrary. This process is called symmetry "breaking", because such transitions usually bring the system from a symmetric but disorderly state into one or more definite states. Symmetry breaking is thought to play a major role in pattern formation.
In his 1972 Science paper titled "More is different" Nobel laureate P.W. Anderson used the idea of symmetry breaking to show that even if reductionism is true, its converse, constructionism, which is the idea that scientists can easily predict complex phenomena given theories describing their components, is not.
Symmetry breaking can be distinguished into two types, explicit symmetry breaking and spontaneous symmetry breaking, characterized by whether the equations of motion fail to be invariant or the ground state fails to be invariant.
When the SU(2) symmetry is broken
by the Higgs mechanism,
the W bosons acquire mass
and become the well-known W^+ and W^-
bosons discovered at CERN.
So before the breaking, the Ws had no mass.
Did they have charge?
If yes: No particle is known
without mass but with charge. Are the W...
Was the early spontaneous symmetry breaking caused by exponential expansion in the first instant of standard theory?
Is that the reason that the early Big Bang universe is thought to have contained equal amounts of matter and anti-matter (produced by spontaneous symmetry breaking)?
Does...
On spontaneous symmetry breaking and Higgs’s mechanism of mass production
From lectures: L. Peak and K. Varvell. The Physics of the Standard Model.
Full Lagrangian for fermion and photon
Combine the gauge-invariant Lagrangian density describing a fermion field in the presence of an...
Interesting new paper from John Moffat:
http://arxiv.org/abs/0709.4269
Introduces a non-local, finite QFT that dynamically generates boson and fermion masses as loop corrections. Experimental evidence for the theory will be visible in WW scattering at the LHC (coupling goes to zero, which...
How would one know in general, whether an original gauge symmetry in the theory is still gauge symmetrical after symmetry breaking? I mean is there a theorem or something like that?
And the other way around, is there a general way of knowing whether there is the possibility of a hidden, i.e...
Hi,
I have done classical symmetry breaking and now want to understand the quantum one. I have seen the statement that the symmetry is broken if and only if Q|0> not 0. Where |0> is the vacuum and Q is the associated charge of the broken symmetry. Why does this imply symmetry breaking? The way...
Dear PF,
Could anyone help me to understand the following issue:
I don't understand the formation of Goldston bosons in chiral symmmetry breaking. Namely - suppose there is only fermion fields Lagrangian and due to some reasons the fermion field obteins VEV - <0|psi^bar psi|0> is non...
I often have this problem when reading physics books (the kind I can understand) where, because I'm only in High school math, the author explains only in analogies, and the analogies sometimes don't make logical sense.
I'm reading Steven Weinberg's "Dreams of a Final Theory" and I got to the...
Hello. I've got a QFT final tomorrow, and one question is still bothering me.
Consider two lagrangians.
The first one is
L = \frac{1}{2} D_{\mu} \vec{\phi}.D^{\mu} \vec{\phi} + \frac{m^{2}}{2} \vec{\phi}.\vec{\phi} - \frac{\lambda}{4} \left(\vec{\phi}.\vec{\phi}\right)^{2}
The second...
Dear PF,
Could anyone advise me where I can find the following book:
Dynamical symmetry breaking in quantum field theories - Miransky, V.A.
Is itt possible to download from somewhere?
Cheers
George
I would much appreciate if anyone could give me some tips/referencess on Dynamical Symmetry Breaking. Namely detailed referrence on Namby Jona-lasinio model of mass for particles.
In Chapter 6 of the Antigravitation Engine Site, the symmetry breaking in vacuum is studied as follows.
11. The symmetry breaking in vacuum
It can be known from Section 8 of this chapter that everywhere in vacuum there are non-present-time foggoids, whose gfm ball particles have a dominant...
Symmetry "breaking"
Greetings !
I'd like to ask and possibly discuss questions
about symmetry :
1. I heard that there is a 2% lacking symmetry in
weak nuclear force reactions. Does this
mean energy-conservation (and other physical laws)
are violated ?!
2. Does the HUP possibly...