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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.


Sep
16
comment Was Max Born the first to notice a connection between quantum mechanics and randomness?
@CuriousOne - orthodox QM for more than 80 years has been, the wavefunction evolves deterministically according to Schrodinger's equation, until an observation is made, at which point the wavefunction jumps RANDOMLY to some eigenstate of the observable, with a probability equal to ... blah blah, I'm sure you know this.
Sep
16
comment Was Max Born the first to notice a connection between quantum mechanics and randomness?
@CuriousOne: Suppose I'm going to measure some observable and I start with a superposition of eigenstates, |x>+|y>. According to QM, the system can start in the state |x>+|y>, and then end up in the state |x> or the state |y>. If it was completely deterministic, there would only be one possible end state.
Sep
16
comment Was Max Born the first to notice a connection between quantum mechanics and randomness?
@CuriousOne: you write "[quantum systems] are perfectly causal...", but then "the outcome of an individual measurement... is not fully determined". The last part is where randomness enters, according to quantum theory.
Sep
11
comment Was Max Born the first to notice a connection between quantum mechanics and randomness?
As for the remarks about i and the existence of the universe, I can only guess at what you have in mind.
Sep
11
comment Was Max Born the first to notice a connection between quantum mechanics and randomness?
@CuriousOne - what are you talking about? In quantum mechanics, the value of a measured quantity does not have a cause, it's a random variable distributed according to the Born rule. If your physical theory has a causal explanation for the actual outcome of the measurement, then your theory is something other than quantum mechanics.
Sep
10
comment Are double-slit patterns really due to wave-like interference?
+1 for the link to the QFT calculations.
Sep
7
comment Quantum Yang-Mills Theory and AdS/CFT
How is that paper related to the Millennium problem?
Sep
2
comment Quantum Yang-Mills Theory and AdS/CFT
Mapping the problem to string theory (if that could be done) would not in itself be an increase in rigor, since string theory uses the same QFT concepts that lack rigorous mathematical formulation. (btw apparently the work of Fields Medalist Hairer will help with the latter.) But mapping it to string theory might be a source of ideas or intuitions which could then be inspiration for a proof.
Aug
16
comment M-Theory and computer simulation
Equations in advanced theoretical physics are often very hard to solve or approximately solve. The form of M-theory that is easiest to simulate might be the BFSS matrix model, but that's M-theory with 10 of the space dimensions large, rather than just 3.
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.