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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
16
comment Common false beliefs in Physics
Also, I don't think anyone believes 5, 6 and 7 are arguable at best, and 8 is only stated by people who believe Maxwell's equations, so that the principle of relativity plus the validity of Maxwell's equations implies the constancy of the speed of light.
Aug
16
comment Common false beliefs in Physics
The point of a laser pointer on a far away wall can move faster Regarding point 3, nothing moves faster than light in vacuum, this is not true. Phases of a light wave in a material, virtual particle trajectories contributing to a path integral, a pre-planned crowd "wave" in a large stadium, and other immaterial things. It is material objects and information are constrained by the speed of light.
Aug
16
revised Examples where an ill-behaved function leads to surprising results?
fix reflection error
Aug
16
answered Examples where an ill-behaved function leads to surprising results?
Aug
16
comment Is the S-Matrix the only quantum field observable?
The S-matrix is nontrivial for nonfree models in 2d because it includes the phase shifts.
Aug
16
comment Einstein's postulates $\leftrightarrow$ Minkowski space for a Layman
This is the Minkowski version of the Chinese proof of the Pythagorean theorem.
Aug
16
revised Einstein's postulates $\leftrightarrow$ Minkowski space for a Layman
copy-edit
Aug
16
revised Einstein's postulates $\leftrightarrow$ Minkowski space for a Layman
copy-edit
Aug
16
answered Einstein's postulates $\leftrightarrow$ Minkowski space for a Layman
Aug
16
comment Einstein's postulates $\leftrightarrow$ Minkowski space for a Layman
@Roger: the velocity addition formula, the explanation of Fizeau's experiment, the relativistic E,B transformation formulas, the correct equations of motion, the identity between induced EMF by motion and by changing magnetic fields, and the formulas for the longitudinal and transverse mass of an electron, were all new to this paper. It was considered backward by Poincare because it assumed the symmetry is true and derived the dynamical equations, instead of using the dynamical equations to find the symmetry. History has long ago rendered its verdict on which approach is more fundamental.
Aug
16
comment Did Einstein prove $E=mc^2$ correctly?
His paper is so trivial to refute, it is hardly worth the bother: he is saying that Einstein is wrong to use the nonrelativistic expression for energy in his argument, but the velocity of the object that Einstein is considering is entirely due to shifting reference frame, and the velocity of the shift can be infinitesimally small. In addition, while Einstein might have asked "what is the kinetic energy of the body" to determine the loss of mass, the system loses mass when you ask "what is the linear momentum of the body (as explained in my answer). The only relativistic thing is the light.
Aug
16
answered History of interpretation of Newton's first law
Aug
16
comment Planck's Law in terms of wavelength
Wikipedia is not wrong, the spectrum is a density and contains a differential factor $d\lambda$ which you need to transform to get the correct density.
Aug
16
answered The entropic cost of tying knots in polymers
Aug
15
answered Common false beliefs in Physics
Aug
15
answered Common false beliefs in Physics
Aug
15
comment What is the difference between a measurement and any other interaction in quantum mechanics?
There is a problem with the literature of philsophy--- its mechanisms of peer review are not moderated by neither experimental input nor rigorous proof, so the methods of evaluation are entirely political. The history of thought does not suggest that political competition of ideas without external moderation using experiments or rigor can ever be successful.
Aug
15
comment What is the difference between a measurement and any other interaction in quantum mechanics?
The agent doesn't have to be a person--- it's a sort of disembodied consciousness, and it could even be a collective. This doesn't have any bearing on the issue of whether consciousness is computation because a computer interacting with a quantum system is just as mysterious as a person collapsing the wavefunction. A computer can't compute in quantum mechanics without doing a measurement at the end to see what was computed. If we think the computer somehow has a "sense" of what its memory is, this leads to a collapse of the wavefunction relative to this sense.
Aug
15
answered Is Mach's Principle Wrong?
Aug
15
comment Is causality a formalised concept in physics?
Anixx is not wrong, just taking a nonstandard philosophical path through a certain well-trod thicket.