106,023 reputation
7146302
bio website motls.blogspot.com
location Czech Republic
age 40
visits member for 3 years, 10 months
seen 11 hours ago

Hi, I am a string theorist and a publicist.


May
13
comment Why is the steam from cooling towers not used?
I just want to confirm it's a sensible estimate. One cooling tower of the Czech Temelín nuclear power plant evaporates 300-400 liters or kg of water per second. There are four of them. Their height is 150 meters. images.google.cz/images?q=temelin&biw=1031&bih=783 Temelín produces 2 x 1,000 MW. - Just one conceptual comment: you calculated the potential energy. Of course, there is latent energy/heat of the condensation that is actually comparable to 1,000 MW. If one could get it back from the vapor, that could increase the efficiently substantially. But steam engines are not perfect...
May
13
revised What is the most natural definition of the weak hypercharge coupling constant if grand unification is wrong?
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May
13
comment What is the value of the fine structure constant at Planck energy?
it was a pleasure although it took some time. Cheers, LM
May
13
revised What is the most natural definition of the weak hypercharge coupling constant if grand unification is wrong?
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May
13
answered What is the most natural definition of the weak hypercharge coupling constant if grand unification is wrong?
May
13
revised When will PLANCK release all-sky CMB anisotropy measurements?
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May
13
revised When will PLANCK release all-sky CMB anisotropy measurements?
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May
13
answered When will PLANCK release all-sky CMB anisotropy measurements?
May
13
revised Why doesn't string theory have a mass gap?
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May
13
revised Why doesn't string theory have a mass gap?
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May
13
revised Why doesn't string theory have a mass gap?
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May
13
answered Why doesn't string theory have a mass gap?
May
13
answered Please justify invoking logical positivism to causal patches and black hole interiors in quantum gravity!
May
13
comment Wavefunction normalization
Could you please specify which "things" are supposed to cancel? The norm surely can't cancel because it is a sum of positively semidefinite terms. Your function is a combination of plane waves so much like a single wave, its normal can't be one. One could normalize similar combinations to a wave function if the $A/B$ ratio were determined as a function of $k$ and if it were continuous. In that case, $|A|^2+|B|^2$ would be normalized exactly in the same way as $|A|^2$ is normalized if there's only one term, one plane wave.
May
13
awarded  Nice Answer
May
12
comment What is the value of the fine structure constant at Planck energy?
Dear @Claude, I assure you that my answer does answer your question. Read the discussion below my answer to catch at least many of the numerous mistakes you are making in your reasoning and which also prevent you from seeing that my answer does answer your question.
May
12
comment What is the value of the fine structure constant at Planck energy?
Dear @Claude, you're confused. The left graph on www-ekp.physik.uni-karlsruhe.de/~deboer/html/Forschung/… shows the standard $U(1)\times SU(2)\times SU(3)$ couplings of the Standard Model I was talking about. None of these three constants ever becomes $1/137$: none of them is the electromagnetic fine-structure constant. The fact that the $U(1)_Y$ coupling in the graph starts at $1/60$ is no mistake while $1/137$ would be mistake. As I explained, you can't extrapolate "the" $1/137$ coupling because it's electromagnetism which breaks down above 100 GeV.
May
12
comment Does the Planck scale imply that spacetime is discrete?
Yes, it does. Even if one could find nearly flat-space solutions in LQG, which no one can (and chances are that it's because there's no flat space in LQG), it would still be true that it would violate the Lorentz invariance much more strongly than the experimental upper bound. The spin networks or, in the path integral language, the spin foam is a (not so) modern version of the 19th century luminiferous aether. It not only violates the Lorentz invariance but also carries a huge entropy density which instantly slows objects much like a dense $10^{95}\,kg/m^3$ "water" slows down swimmers.
May
12
comment Why don't we consider centrifugal force on a mass placed on earth?
Yes, sure, unless you of course buy gold for a million of dollars and using a different weight, they steal $3000 from you. ;-)
May
12
answered What is the extent of Earth's gravitational pull?