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location New York City
age 41
visits member for 3 years, 4 months
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I do not participate on this site any longer, except to respond to comments regarding my own text, if that text is unavailable in another form. I do not accept the political moderation atmosphere here, it is not compatible with open science. I participate at physicsoverflow.org.


Aug
22
comment Connection between $\Delta x \Delta p \geq \frac{\hbar}{2}$ and $\Delta E \Delta t \geq \frac{\hbar}{2}$
This is what Bohr and Einstein knew, but the quantum formalism makes it hard to make precise. It's correct for waves, of course, just you need to translate to a formalism.
Aug
22
comment Why does tachyon arise in bosonic string theory?
But the theory is inconsistent without GSO projection. The easiest argument is Witten's--- the theory has a gravitino, so it must be space-time supersymmetric, and therefore have no tachyon and come in equal number of bosonic and fermionic particles at each level. The GSO projection is really necessary, it is interpreted as summing over spin structures on the worldsheet, which means certain of the naive modes don't contribute.
Aug
22
comment How would a Lagrangian be used to recover the Schrodinger equation?
The reason your answer was downvoted is, I suppose, that the two different equations are completely separate ideas--- one derives the Schordinger equation as a field equation, the second as an equation for particle amplitudes, so you shouldn't write both together, or at least describe the different ideas of the two formalisms.
Aug
22
comment Best EM/Photon rocket using avalable tech?
You are assuming the energy source isn't carried with the ship, the OP assumed the ship would carry the source. You can definitely push a ship from outside using a mounted energy source, that's not the issue, the issue is to do it when you don't have a momentum-sink, you need to conserve momentum, so you need to eject stuff, and since OP doesn't want to eject stuff, he need to eject photons.
Aug
22
comment Is 3+1 spacetime as privileged as is claimed?
You should clarify "too quick"--- it is difficult to know how quick is too quick. The orbits wouldn't work. But perhaps you could have 4+1d life, with another thing, not planets. Who knows.
Aug
22
comment Quantum mechanics and everyday nature
Friction is not particularly quantum, and "electricity" is too vague, if you mean "electrical conduction", yes, true. But the rest are good.
Aug
22
comment Relative to the speed of light
The intution is not about the formalism, but about how it works. This probably requires a picture to explain, to see the failure of simultaneity, which is the thing people generally fail to get when learning relativity from popular sources (but it's the first thing Einstein discusses).
Aug
22
comment Relative to the speed of light
This answer is wrong, the main effect is the failure of simultaneity at a distance, this makes the speed of light the same in the backward and forward direction in the moving frame.
Aug
22
comment Is normalization consistent with Schrodinger's Equation?
This answer is kind of pointless, it isn't helpful, you can just say "The SE is linear".
Aug
22
comment Is there a maximum number of types of elementary particles?
This is true, but the "particles" we see in accelerators are just the massless particles, and there are a finite number of these. This is probably the best interpretation of the question.
Aug
22
comment Do the laws of physics evolve?
You should know that the large-numbers coincidence is now called the "Hierarchy problem", together with the fact that there are three scales--- the neutrino/cosmological-constant scale at .1 eV, the Higgs scale at 1TeV, and the Planck scale at 10^19 GeV. These are equally spaced in log, hence the large-numbers, and the cc-scale is comparable to the age of the universe, probably as Weinberg suggested, because it's anthropic.
Aug
22
comment Explanation for $E~$ not falling off at $1/r^2$ for infinite line and sheet charges?
Your argument is correct, but the intuition is from field line spreading, so the better way to say it (in such a way that someone else can also understand) is to use Gauss's law, this is the field line counting made clear.
Aug
22
comment What happens to the wave function after applying the D'Alembert operator?
It's true what you say, but it is too formal--- you can just say it without the trivial manipulations, let the reader figure it out.
Aug
22
comment Why is there a deep mysterious relation between string theory and number theory, elliptic curves, $E_8$ and the Monster group?
There is another point, that E(8) is E6xSU(3), and on a Calabi Yau, the SU(3) is the holonomy, so you can easily and naturally break the E8 to E6. This idea appears in Candelas Horowitz Strominger Witten in 1985, right after Heterotic strings and it is still the easiest way to get the MSSM. The biggest obstacle is to get rid of the MS part--- you need a SUSY breaking at high energy that won't wreck the CC or produce a runaway Higgs mass, since it seems right now there is no low-energy SUSY.
Aug
22
comment The General Relativity from String Theory Point of View
This is correct, but the main detail missing is the Ward identity--- this is derived in chapter 2 of Green Schwarz Witten--- a variation in the metric is equal to a graviton insertion, and diffeomorphisms don't count, so you get a Ward identity.
Aug
22
comment Is there any reproducible tested evidence for Ni-H cold fusion?
I should add that the detection method for tritium in heavy water is a blue flash of Cherenkov radiation from the emitted beta electron, and the half-life is short enough to get good counts even at the trace concentrations of ordinary heavy water, and the amount of tritium in cold-fusion heavy water was hundreds of times background.
Aug
22
comment Is there any reproducible tested evidence for Ni-H cold fusion?
Also, there is a nice twist here--- I also explained the phenomenon completely with a "personal, unpublished, pseudoscientific theory" on this website, which is personal, is unpublished, but which has the sole advantage of being correct technically (I checked it, you can do so too). So that the mechanism is now known. So all your comments about theoretical impossibility are certainly unjustified, since I explained how it works theoretically. Regarding the claims of DGT, I agree, they look fraudulent, all the corporate work does, which is why I am asking for reliable experiments on this.
Aug
22
comment Conservation of quantum Noether current
@EdwardHughes: This is entirely accurate. I am not exactly talking about the Ehrenfest theorem, rather the Heisenberg equation of motion (they are actually equivalent). The classical equations of motion are satisfied as operator equations, meaning that the quantum mechanical operators in the Heisenberg representation obey the classical equations of motion. The contact terms are there, but they only modify this at coinciding insertions, it doesn't change the result very much. I have shown this on a recent answer regarding supergravity.
Aug
22
comment Is there any reproducible tested evidence for Ni-H cold fusion?
Palladium Deuterium cold-fusion certainly exists, as tritium was detected by Pons & Fleischmann at Utah, at Bhabha, at Texas A&M by two independent groups (Wolf and Bocris) and also at Los Alamos (but the fellow was not allowed to publish). That settles the question of nuclear effects for good, and there is nothing you can say, unless you can show that all these people were deliberately committing coordinated fraud. You can't mismeasure tritium, it is radioactive with a clear signature, the detection method is 100% reliable at any concentrations, nor can you make tritium chemically.
Aug
21
awarded  Revival