116,086 reputation
7179346
bio website motls.blogspot.com
location Czech Republic
age 41
visits member for 4 years, 7 months
seen 2 hours ago

Hi, I am a string theorist and a publicist.


Apr
24
answered precise definition of “moduli space”
Apr
22
answered Poincare Symmetry in QFT
Apr
22
comment Factor 2 and equations for the weak gravitational field
Your guess where the wrong factor of 2 could have arisen may be right or wrong but I still think that if you show the whole derivation which is right, the OP may still find an error wherever it is, assuming that he or she followed a similar strategy, +1.
Apr
21
answered Baryon asymmetry
Apr
21
comment Why/How is this Wick's theorem?
Apologies but this question seems to be asking "please teach me Wick's theorem" - and it moreover says "do it without teaching me Wick's theorem". Have you tried to study Wick's theorem? At least en.wikipedia.org/wiki/Wick%27s_theorem ? The standard pedagogical treatment answers all your questions. The Wick's theorem is the systematic way to construct such identities that you're looking for. Fermions differ by some signs only. I find it questionable whether copying/rephrasing sections from standard textbook material is a good way to use this server and people's time.
Apr
20
comment Feynman's sum over histories?
Sorry, what are exactly "infinite paths" and what sort of cancellation are you talking about? Your question makes no sense to me. Feynman's path integral is an infinite-dimensional version of $\int d^n x \exp(iS[x_j])$ where $S$ is complicated enough function of the variables $x$. There's no cancellation that is both exact and trivial here. It's a complicated integral which produces a complicated result. We sometimes say that if $S$ varies quickly, most of the terms tend to cancel, so only places of stationary $S$ contribute in some classical expansion, but that's just an approximation.
Apr
20
comment What is a Hilbert space filter?
It's described in the 1999 Lo-Chau article in science, reference 17 here. You may also try to look at www-users.cs.york.ac.uk/schmuel/papers/bp12.pdf It's a filter against any side channel.
Apr
20
revised Does a UV completion of gravity necessarily need to be so drastic as String Theory or LQG?
added 796 characters in body
Apr
20
revised Does a UV completion of gravity necessarily need to be so drastic as String Theory or LQG?
added 796 characters in body
Apr
20
revised Does a UV completion of gravity necessarily need to be so drastic as String Theory or LQG?
added 796 characters in body
Apr
20
answered Does a UV completion of gravity necessarily need to be so drastic as String Theory or LQG?
Apr
20
revised Question about SL(2,Z) duality of string theory/N=4 SYM
added 15 characters in body
Apr
20
comment Did they find a new particle with CMP?
Exactly. And there are many examples like that, including sonic black holes, apparent superluminal motion etc. ;-) Those fields love to produce results that superficially look similar to concepts in fundamental physics because deeply in their bones, they know very well that fundamental physics is more exciting and potentially shocking than their research...
Apr
20
comment Did they find a new particle with CMP?
You sent it 34 seconds before me. ;-)
Apr
20
answered Did they find a new particle with CMP?
Apr
20
revised Is the Mendeleev table explained in quantum mechanics?
added 552 characters in body
Apr
20
comment Is the Mendeleev table explained in quantum mechanics?
Dear DrSAR, the answer to your question is No, there is no joke or irony, neither intended nor unintended, in my answer. It was a well-defined question whether a subset of physics describes some class of observations and the answer is obviously Yes. I think it's good that this question was asked because people - and not only those who love to visit witches to predict the future etc. - often associate elementary low-energy physics such as atomic physics with lots of mystery that doesn't exist. All these things are almost perfectly understood.
Apr
20
answered Question about SL(2,Z) duality of string theory/N=4 SYM
Apr
20
revised Is the Avogadro's constant equal to one?
added 787 characters in body
Apr
20
awarded  Nice Answer