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9h
comment Is it THE Higgs?
To add to Anna's answer, it seems like it's the Higgs of the Standard Model, but it's quite plausible that there will be other "similar" particles in some viable extensions of the Standard Model.
1d
comment How does path integral formulation explain bound states?
The question I posed above is problematic to me, since the final state is not a "fluctuation" off the QFT vacuum, but a bound state. Maybe I'm missing something, but I don't know how to describe it in terms of the creation and annihilation operators of the proton and electron.
1d
comment How does path integral formulation explain bound states?
Once I can compute that, I could use the optical theorem to calculate the one-loop correction from such bound states to the Moller-like scattering of the electron and proton. Going that way, I think there might be a path (forgive the pun) to incorporate the effects of bound states into the formalism.
1d
comment How does path integral formulation explain bound states?
What if I posed the question thus: Consider a QFT of a proton field and an electron field. Initial state: Free electron and free proton --> Final state Hydrogen atom in the 1s state. How would one calculate this transition amplitude?
Oct
26
comment Why loop quatum gravity is considered pseudoscience by some physicists?
As it stands now, the wording of the question is pure flamebait and based on an opinion. If the question were re-worded to ask about specific (reasonably objective) arguments for or against LQG then it might add some value to the forum.
Oct
23
comment Is there some special case where a fermion can mediate a force?
Oops, I didn't mean to put a vev $\langle \rangle$ above. @arivero: Yes, that's what I was wondering -- the composite force mediating degree-of-freedom is again bosonic, now!
Oct
22
comment Is there some special case where a fermion can mediate a force?
I wonder if the fermion loop is equivalent to a composite bosonic operator $\langle \bar{\psi} \psi \rangle$ mediating the force.
Oct
21
comment Effective Field Theories of QCD
@soliton: If you've made any progress in the course, you might be able to answer your own question. I think it will help many others :-)
Oct
20
comment Is there some special case where a fermion can mediate a force?
@arivero, I understand and for the same reason, my answer is measured.
Oct
18
comment Is there a connection between the fluctuation-dissipation theorem and the Green–Kubo relations?
her book :-)
Oct
13
comment $D$-brane and 5th dimensions
The "p" in p-brane stands in for the number of spatial dimensions that a brane covers. The "D" in D-brane stands for something quite different: It states that this brane provides "Dirichlet" boundary conditions for the strings roaming around in space.
Oct
12
comment Gravity as a gauge theory
Though this might not be what the OP had in mind, a recent concept that is becoming interesting is that a gravity theory could be thought of as a product of two copies of gauge theories. For eg, look at: arxiv.org/abs/1004.0476
Oct
8
comment Scalar field divergent mass correction interpretation question (hierarchy problem)
"it's telling me that I have a correction as big as the largest scale in my problem (cut-off scale)" -- that's not quite true. Any corrections to the mass are suppressed by positive powers of the loop factor $\frac{g^2}{16 \pi^2}$.
Oct
3
comment Dilaton field and Scale symmetry breaking
Interesting question. From what I understand, you are asking how SSB of scale symmetry in QFT (by dimensional transmutation) can be seen from the perspective of the dilaton. I wonder if one can do a spurion analysis.
Oct
3
comment Calculate the equivalent resistance between A and B
For more information on how to approach "unbalanced" bridges, check here: ibiblio.org/kuphaldt/electricCircuits/DC/DC_10.html
Oct
3
comment Calculate the equivalent resistance between A and B
This setup is called the Wheatstone bridge. Since the bridge is "balanced" (read he Wikipedia article) there will be no current in the $5 \Omega$ resistor and you can essentially "disconnect" it.
Sep
27
comment What does it mean to “convert energy into time”?
Quite possibly slips between what the scientist intended to say, what was actually said, what was heard by the journalist, what the journalist thought was said, what the journalist expressed that as, in the article and what the editor thought it should be written as.
Sep
25
comment Do gravitational fields exist in vacuum region?
Defining the notion of "energy" in general relativity is a tricky thing -- en.wikipedia.org/wiki/Mass_in_general_relativity
Sep
21
comment Is the ground state of a QFT always a pure state? And excited states are mixed?
Practical comment: Based on my experience, I would suggest you to be cautious about taking statements at face value, in that line of the literature (EE+holography, etc). I got the feeling that people sometimes overstated the generality of their result which might be based on a very specific computation.
Sep
21
comment Massless integrals in dim-reg
Observation: When the higgs mass is set to zero, the SM is classically scale invariant. So, the question is, can that symmetry be broken quantum mechanically, and if so, will it be suppressed in any manner.