Recent content by QFT1995

Okay, but people say things like, the theory is invariant under SU(3) yet they provide no extra details. What is usually meant by that?

If I have a wavefunction ##\Psi(X)## that is invariant under the group ##Z_2##, what specifically does that mean? There can be several operators that are representations of the group ##Z_2##, for example the operators $$\mathbb{Z}_2=\{ \mathbb{I}, -\mathbb{I} \},$$ or $$\mathbb{Z}_2=\{...

But neither is the wavefunction in QM? I'm sure you would care if you had two different answers for the wavefunction when solving Schrödinger's equation even though it's not physically observable. Also, you can tell the physical mass of the particle from the propagator so surely it matters if...

My question is why is it okay that two different regularizations of a one loop contribution to the full propagator give two different answers? Are the finite parts for all regularization schemes the same? If that's the case, do the divergent parts only contain information about high energy...

Does it have something to do with that in the low energy limit, the kinetic terms are irrelevant compared to the potential terms?

Why aren't the right handed Weyl spinors included?

I'm specifically referring to these slides Supersymmetry - Holomorphy on pages 7 and 8. Why is the mass of the superfield defined as \frac{\partial^2W}{\partial \Phi_H^2} and why are the equations of motion \frac{\partial W}{\partial \Phi_H}= 0 and not \frac{\delta \mathcal{L}}{\delta \Phi_H}= 0?

Okay however I was asking if in principle it exists and that we just haven't found it or is it impossible to construct?

There's no explicit form for the full vacuum |{\Omega}\rangle on there. I was wondering if in principle it can exist as an algebraic expression. Also the creation and annihilation operators are just defined by how they act on the free vacuum |{0}\rangle as an abstract definition. I'm not sure if...

In theory, does an algebraic expression exist for the ground state of the Klein Gordon equation with \phi^4 interactions in the same way an algebraic expression exists for the simple harmonic oscillator ground state wavefunction in Q.M.? Is it just that it hasn't been found yet or is it...

If I haven't heard back as of yet, does that mean that I haven't been shortlisted? When are interviews usually held and when do people usually find out? My feeling is that if I haven't heard back from the universities as of yet, I haven't been shortlisted but I'm hoping someone more...

Ah thank you. This is the point I was missing. One last question. If I have two expressions say $$ \mathcal{T} A(\phi(x_1),\phi(x_2)\dots)=\mathcal{T}B(\phi(x_1),\phi(x_2)\dots),$$ does that mean ## A(\phi(x_1),\phi(x_2)\dots)=B(\phi(x_1),\phi(x_2)\dots)##? Here ##A## and ##B## are functions of...

If you look on page 5 eq 4.2 of the paper http://www.sbfisica.org.br/~evjaspc/xviii/images/Nunez/Jan26/AdditionalMaterial/Coleman_paper/Coleman_paper.pdf (I have linked the paper here), the former notation is written.

Okay thank you. Also is $$ \mathcal{T} \langle 0 |\bigg\{ \phi(x_1) \phi(x_2)\dots \bigg\}|0\rangle $$ the same as $$ \langle 0 |\mathcal{T} \bigg\{ \phi(x_1) \phi(x_2)\dots \bigg\}|0\rangle $$ where ##\mathcal{T}## is now on the inside.

Okay thank you. If I apply normal ordering followed by time ordering, is that identical to just applying time ordering? In the same manner, if I apply time ordering followed by normal ordering, it that identical to just normal ordering? i.e. are $$\mathcal{T}\hat{N}= \mathcal{T}$$ and...