3,402 reputation
1627
bio website taufunctionsquared.blogspot.c…
location
age
visits member for 3 years, 6 months
seen 14 hours ago

Physics Stack Exchange users whose comments are worth studying include Lubos Motl and Ron Maimon (now at http://www.quora.com/Ron-Maimon and http://www.physicsoverflow.org/user/Ron+Maimon). Also see http://arxiv.org/abs/hep-ph/0207124 for a review of physics since the standard model.


May
30
comment How come gravity is $\mathcal{N}=8$? Why is graviton spin 2
Actually they are related - it takes 8 supersymmetry transformations to go from the spin=+2 graviton to the spin=-2 graviton.
May
15
comment are sub-atomic particles really particles or mere concepts in our minds?
Quantum mechanics is an unusual theory because it gives probabilities for going from one event to a later event, without providing a definite picture of what happens in between. But there are many ideas out there regarding what happens in between (see: "interpretations of quantum mechanics"). Henry's instrumentalist idealism is one of the least sensible options.
May
15
comment are sub-atomic particles really particles or mere concepts in our minds?
Anyway, the specific quote by R.C. Henry should not be used as a guide to anything. There is no sense in which quantum mechanics has shown the nature of the universe to be mental or that "nothing exists but observations"...
May
12
comment are sub-atomic particles really particles or mere concepts in our minds?
Are concepts in our minds really concepts in our minds or mere concepts in our minds?
May
4
comment What are the implications of the possibility that the BICEP2 results are caused by a self ordering scalar field transition?
It would mean (1) that conclusions about inflation deriving from BICEP2 (e.g. that inflation occurred at the GUT scale) were uncertain again (2) that in addition to the Higgs field, there were many other scalar fields in nature... But now see arxiv.org/abs/1404.3855 : they calculate the effects of SOSF and say it's different in the details from what BICEP2 saw.
May
4
comment Final theory in Physics: a mathematical existence proof?
Godel's theorems are not a barrier to a theory of everything. After all, Godel's theorems are true, and yet arithmetic still exists and it's possible to say what its basic entities and relations are. The same can be true of physics.
Apr
13
comment why do the electroweak vacuum have to be charge and color neutral?
+1 for the "real hard question". Is there a formal phase rotation that could undo any apparent misalignment?
Apr
13
comment Is there a SQCD gluino string, similar to the gluon string?
Just to clarify the clarification... Sakai-Sugimoto is based on a supersymmetric theory (Type IIA string theory), but SUSY is broken by boundary conditions in one of the compact dimensions. cc: @Frederic Brünner
Apr
5
comment How much computer power would we need to model every physical aspect of the universe
arxiv.org/abs/quant-ph/0110141 ... I mention this paper, not because I believe its particular answer, but just because it attempts the calculation.
Mar
11
comment Dark matter and tides
Lex: You should consider whether your reasoning also applies to the visible matter of the galaxy. Why isn't there a specifically galactic component to Earth tides, resulting from the visible matter throughout the galaxy?
Feb
28
comment Renormalization and the Hierarchy Problem
"we have many reasons to believe that we should pick ~ M_P" Someone should state these reasons.
Feb
21
comment How can we get the mass of an uncharged proton?
The question makes sense but it is underspecified. It's like saying, what would history be like if there were three sexes rather than two; there would be many possible biologies and "possible worlds" with three sexes, and the effect on human society would surely be very different depending on the details. Analogously, any answer to this question has to start by selecting a particular scenario for the "neutral proton". e.g. It could be like the standard model, but the individual quarks are all electrically neutral.
Feb
21
comment Is it possible that there is no theory of quantum gravity?
en.wikipedia.org/wiki/Induced_gravity
Feb
10
comment Backward Time Flow?
See "Cryptozoic" by Brian Aldiss.
Feb
6
comment Does anyone take the Wightman axioms seriously?
"The question sounds like this, for a classical physicist: Does anyone take Lagrangian mechanics seriously?" Lagrangian formulation is used in actual physics. But does anyone ever use a Wightman-axiomatizable QFT for anything? So far as I know, Wightman axioms do not apply to renormalizable QFT, which excludes the whole of particle physics. But maybe some "Wightman-able" theory is used in condensed matter?
Feb
5
comment Are the recently observed Dirac monopoles separable?
Why is it a major breakthrough?
Jan
24
comment Why is the mass of a Kerr black hole proportional to it's angular momentum?
... and I would guess that the real answer may come from the holographic principle and the "Kerr/CFT duality", which is still a subject of research... I may try to turn all this into a proper answer.
Jan
24
comment Why is the mass of a Kerr black hole proportional to it's angular momentum?
But explaining the exact constant of proportionality may be more difficult. See the discussions at physics.stackexchange.com/questions/33473/… ... the explanations are a bit stiff and unilluminating, and the exact calculations only apply in the "weak-field" case. So there are mathematical depths here that are not yet understood...
Jan
24
comment Why is the mass of a Kerr black hole proportional to it's angular momentum?
As for why the Schwarzschild radius is proportional to the mass (and not e.g. proportional to some power of the mass), well, gravitational force is proportional to mass even in Newton's theory. It would have something to do with that, but expressed in the language of general relativity. Again, this deserves an exact answer...
Jan
24
comment Why is the mass of a Kerr black hole proportional to it's angular momentum?
As for the relation between mass and radius, the "radius" is the distance from the center to the event horizon, i.e. to the point of no return for objects that fall in, the place where the escape velocity equals the speed of light. If a black hole gains mass by absorbing something, its gravitational field will be stronger (because there is more mass) and it will get bigger, the point of no return will now be further out. So the radius goes up with the mass; it's directly, not inversely, proportional...