Questions tagged [symmetry]

Question 1

In general relativity, the black hole region (B) of an asymptotically flat spacetime $M,g$ is defined globally as $$ B := M \setminus J^-(\mathscr I^+), $$ and the (future) event horizon is its ...

Question 2

Consider a generic spatial metric $$\mathrm{d}\ell^2 = \gamma_{ij}(\vec{x}) \, \mathrm{d}x^i \mathrm{d}x^j.$$ Assume isotropy of the universe around the origin. Then the metric can only depend on the ...

Question 3

In the derivation of the Reissner-Nordstrom (RN) metric, the field components only take $(t,r)$ and not mixed components with $\theta$ and $\phi$ but does the assumption of spherical symmetry imply ...

Question 4

I recently read about the Wu experiment, but I’m missing something about parity. As I understand it, basic EM would already violate parity. Apparently, it doesn’t, but I’m wondering e.g. what’s ...

Question 5

In a QFT with Euclidean signature, the correlation functions can only be well-defined in a time-ordered manner (This is Claim 1 on Page 2 of Simmons-Duffin's lecture note). For example, a scalar 2pt ...

Question 6

When solving an equation of motion with spherical symmetry using the WKB approximation, one usually encounters a centrifugal term that diverges as $$ \sim \frac{l(l+1)}{r^2}. $$ What is the ...

Question 7

I've recently started learning about topological quantum field theories (via the Atiyah–Segal axioms), and noticed that I haven't seen any mention of symmetries present. Considering how important ...

Question 8

From wikipedia https://en.wikipedia.org/wiki/Wigner%27s_theorem For unitary case $$\langle U \Psi, U \Phi \rangle = \langle \Psi, \Phi \rangle .\tag{1} $$ If I apply the definition of adjoint https://...

Question 9

Why does the dipole moment have to be perpendicular to the mirror plane in systems with $C_{1h}$ point group symmetry? I am trying to understand the dipole emission of point defects in solid-state ...

Question 10

I am studying fluid dynamics and there is a section in our textbook that handles fluids at rest. It starts by mentioning that for fluids at rest ($\vec{v}=0$) the sheer stresses have to vanish and ...

Question 11

I am learning QM and trying to understand the (absence of) SSB in QM. I have read statements from several posts in the forum about the absence of SSB in few-body QM (and I'm not sure if they are ...

Question 12

I am having trouble understanding how Charge Conjugation is defined in Fock Space and in particular when applied to Bloch Hamiltonians. In particular I would start by defining the PH operator ($P$)in ...

Question 13

I'm trying to define a Particle-Hole symmetry operator in the CAR Algebra in a general way. I am finding very confusing to understand weather it should be treated as a linear or antilinear operator ...

Question 14

While working on calculations regarding dipole moments in quantum dots, I noticed an interesting difference between the form of magnetic and electric dipole moment operators in quantum mechanics (bold ...

Question 15

I have a question about higher form symmetries. I can't find anything about this in the literature. The story you usually hear is: higher form symmetries are always abelian because the topological ...

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Questions tagged [symmetry]

In a stationary, asymptotically flat spacetime, when does a Killing horizon coincide with the event horizon?

Most general isotropic spatial metric from Schur's lemma

On the derivation of the Reissner-Nordstrom (RN) metric [closed]

Parity violation clarification: Wu experiment

Time ordering vs symmetry transformation in Euclidean correlation functions

Centrifugal term in cylindrical coordinates

Do TQFTs have a notion of symmetry?

Does Wigner's theorem only imply left inverse?

Dipole moment operator and $C_{1h}$ point group symmetry

Why is the Stress Tensor a Diagonal Matrix for Static Fluids?

Spontaneous symmetry breaking in quantum mechanics

Particle-Hole Symmetry in Bloch Hamiltonians and Fock Space

Particle-Hole symmetry in the CAR Algebra

What symmetries constrain the magnetic dipole moment to be proportional to angular momentum?

Do topological operators for higher form Symmetries have to be embeddable in a single time slice?

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