Symmetries play a big role in modern physics and have been a source of powerful tools and techniques for understanding theories and their dynamics. We say that something is symmetric if there is some transformation we can perform on that object that leaves some property unchanged. The set of symmetry transformations of an object forms a group, and the name of this group is used as the name of the symmetry of the object.
Questions tagged [symmetry]
3217 questions
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Lorentz invariance and the vacuum expectation value of fields with spin > 0
I had a question about Moduli space, which I was reading about here, but then I read this sentence:
"Lorentz invariance forces the vacuum expectation values of any higher
spin fields to vanish."
Can someone explain how exactly this happens? Or…
Joman
- 193
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Why does physics have so many symmetries?
I have just found out that in order to modify mass in his special theory of relativity, Einstein assumed that energy and momentum are always conserved.$^\dagger$ I think surely there are other ways to fit the data. It makes me wonder: is there a…
Shing
- 2,774
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Symmetry arguments in solving problems
There was a question which involved calculation of final charges on two spheres when one uncharged and the other having charge $Q$ were brought in contact with each other. (radius same). If potential concept is applied charge will flow until…
vas
- 103
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Why do humans have bilateral symmetry?
About the eyes I know that it requires for gauging distance as in Modern 3D cameras have two sensors. And two ears for sound source localization using differences in levels and timing (But not yet two microphones in mobile phones/other devices).…
ruben
- 143
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Relation between Homogeneity and Isotropy of space?
As per my understanding so far, homogeneity of space doesn't require a special vantage point (all points in space are "equivalent" to each other) and is a universal statement in that sense; whereas for the isotropy of space, we talk with respect to…
nmnphy
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Hoberman sphere symmetries
I assume everyone here is familiar with the Hoberman Sphere. Fun toy, by the way. My question is this : The sphere is an icosododecahedron. Suffice it to say, it has a set of isometries which define it. Now, when the sphere is expanded, it has…
MarkLeFont
- 11
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Is separability a necessary and sufficient condition for symmetry?
I just wondered about the following issue. Take General Relativity and the Kerr solution. The separability of the Hamilton-Jacobi equation (or equivalently the Klein-Gordon equation in this curved space-time) implies the emergence of the Carter…
riemannium
- 6,491
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isotropy for additive manufacturing
Generally isotropy depends upon the direction of material properties.For the general materials it is isotropic most of the time. But for additive manufacturing the parts are built layer wise, so is it possible for it to be isotropic in nature?
mPm
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Why contraction of symmetry and anti-symmetry is zero?
This term is appeared in the process of deriving continuous eq. from maxwell's eq.
$1 \over 2$$\varepsilon_{i,j,k}$($\partial_i$$\partial_j$+$\partial_j$$\partial_i$)$B_k$
my professor said
$\varepsilon_{i,j,k}$ is anti-symmetry, and…
og zo
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Does isotropy depend on the location of the origin from where we see the medium?
Let us say we have a charged non-conducting sphere having a spherically symmetrical charge density $\rho (r)$ that decreases as $r$.
Ignoring all other properties, If we positon ourselves in the center of the sphere, the medium will appear isotropic…
Hilbert
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"Geometric" symmetries
A symmetry of a dynamical system is a diffeomorphism of the configuration space which sends solutions of the equations of motion to solutions of the equations of motion. That is, $A$ is a symmetry if
$$x(t)~\text{is a physical evolution of the…
David Roberts
- 987
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Symmetries, source terms, boundary conditions
If I recall correct you can say that e.g. the electric vectorfield is only a function of the radius if the source terms (charge) is spherical and uniform so that a group action that rotates space makes the source term invariant. Is there some…
Emil
- 693
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Galilean invariance/ scale invariance of KPZ
I have problems with understanding what the Galilean invariance of KPZ
means and how it is connencted to KPZ scale invariance?
How can I see that KPZ is scale invariant?
Why this symmetry impose that the MSR action depends only on the combinantion…
Agnieszka
- 175