561 reputation
34
bio website
location Russia
age
visits member for 2 years, 11 months
seen May 5 '12 at 20:03

Scientist


Jul
20
comment What software programs are used to draw physics diagrams, and what are their relative merits?
I mean AIP or APS journals. Some macropackages may not be managed there or cause reduction of picture quality.
Jul
20
comment What software programs are used to draw physics diagrams, and what are their relative merits?
Is it permitted for use in journal publications?
Jul
19
comment argument about fallacy of diff(M) being a gauge group for general relativity
If you could define invariance in such a way, any differential equation would become invariant, because it is known, how to rewrite differential equations for different coordinate systems. So Maxwell equations should not be considered as diff(M) invariant only because you may write that in curved coordinates.
Jul
14
comment Charged Black holes - What is the Interest in those?
"However, for one who has crossed the event horizon in the Reissner-Nordstroem geometry, there would appear to exist an infinite range of rich possibilities for experience, that are denied to one who crosses the event horizon in the Schwarzschild geometry. For the latter person, there is, as we have seen, no alternative to being inexorably propelled towards the singularity at r = 0." - ibid
Jul
13
answered Charged Black holes - What is the Interest in those?
Jul
13
comment What does a frame of reference mean in terms of manifolds?
I guess, it is discussed an approach originated by Ashtekar and widely used in loop quantum gravity, but in general we may talk about tangent bundle without need to talk about spin structure ... yet without that matter could not exist.
Jul
13
answered What does a frame of reference mean in terms of manifolds?
Jul
12
comment Disproof of Bell’s Theorem
Clifford algebras are used "in the context of Bell's theorem" since Tsirelson work 1993 and so it is not "a new idea".
Jul
11
revised Returning Light
fixed grammar
Jul
11
answered Returning Light
Jul
10
revised Is it viable to convert nuclear waste into safe isotopes?
edited body
Jul
10
answered Is it viable to convert nuclear waste into safe isotopes?
Jul
10
comment Could cell-phone radiation cause cancer?
More actual example: NIST wrote about hazard of 20 mW laser pointer, but 100W classical source is not considered as something dangerous, yet it is 5000 more. So accurate consideration of difference between quantum and classical sources may be important.
Jul
10
comment Could cell-phone radiation cause cancer?
Term "multiphoton" usually have other meaning so your terminology was not clear for me. Amount of photons does not matter much, laser may emit even more photons than some classical source.
Jul
9
comment Could cell-phone radiation cause cancer?
Multi-photon effects from a classical device?
Jul
9
comment Is spacetime simply connected?
Recently preprint appears there also the WMAP data is used, but with claim about possibility of multiply-connected Universe with spatial topology $\mathbb T^2 \times \mathbb R$. It seems not published in a journal yet, but the idea already reproduced in Wikipedia.
Jul
8
comment Is spacetime simply connected?
It is something like that
Jul
8
comment Is spacetime simply connected?
What about eternal string singularities? BTW, it seems, the cited paper only prevent to “probe topology” and even in such a case may have some lacuna in the proof.
Jul
7
comment Is travel to the distant future possible without massive energy expenditure?
It may be even worst, e.g. radius of last stable circular orbit is 6M (then 2M is event horizon).
May
30
comment How many qubits are needed for useful computation?
In the estimation I also used the fact, that brute-force simulation on classical supercomputers nowadays is limited to 24 qubits or so.