Reputation
9,295
Top tag
Next privilege 10,000 Rep.
Access moderator tools
Badges
15 41
Newest
 Nice Answer
Impact
~366k people reached

18h
comment Selection rule used in singlet/triplet recombination in LEDs
@user5419 - No. Nothing in my answer is based on the assumption that light has zero angular momentum. I also never said light "does not couple", only that it couples very weakly.
Jan
29
comment How Special Relativity causes magnetism
@ChrisWhite -- For what it's worth, most serious theoretical physicists believe that magnetic monopoles exist in the universe, but that they're very very rare. I don't think it matters for the issue under discussion though.
Jan
29
comment How Special Relativity causes magnetism
I didn't say that electricity and magnetism were "symmetric" in the sense that you're using the term. (Please re-read my answer, I was discussing asymmetry of pedagogical emphasis.) Any 6-year-old can tell them apart. I only said that the relationship between electricity and magnetism is not cause-and-effect: They are equally fundamental parts of physics.
Dec
30
comment Translating Electronic Bands back to first Brilluoin Zone
I recently put an explanation and image on wikipedia on this topic: See en.wikipedia.org/w/… and the red+blue graphs on the right.
Dec
29
comment Has there been any experimental verification of Jeremy England's theory of dissipation-driven adaptation?
I don't understand that comment. Surely you know that Carnot's limit applies to all engines, including those that operate extremely far out of equilibrium. Indeed every "thermodynamic limit" proof I've ever seen, whether Carnot or England or Landauer or Landsberg, applies to all systems, not just (quasi)equilibrium systems.
Dec
29
comment Has there been any experimental verification of Jeremy England's theory of dissipation-driven adaptation?
@CuriousOne - The website englandlab.com is not commercial. It is a research group website that happens to use a memorable "com" address.
Dec
29
comment Has there been any experimental verification of Jeremy England's theory of dissipation-driven adaptation?
England's paper, like Carnot's law, is an attempt to draw conclusions directly from the laws of thermodynamics. If by "triviality" you mean "unambiguous consequence of widely-accepted axioms" then both Carnot's law and England's paper are "trivialities"...as is every theorem in mathematics and much else. That's not how most people use the term "triviality" though. Is that what you mean?
Dec
22
comment Temperature of fusion in the Sun vs. fusion in controlled experiments on Earth
You should also add that fusion reactions on earth have an extremely low duty cycle (the reactor is turned on for a tiny fraction of a second, off for a long time, ...), whereas the sun keeps it going continuously.
Dec
4
comment How can I change the angle of a laser without mechanical aid
ditto a spatial light modulator with phase control
Oct
31
comment Magnetic monopole bound state
You can say "there might be multiple different particle species with magnetic charge, but having different mass, spin, lepton number, etc."---and you can say that without discussing duality transformations. In fact, I just did so! And incidentally, this fact, while true, doesn't mean that the original question is unanswerable. Physicists have pretty specific ideas about what magnetic monopoles particles are likely to look like, for example 't Hooft–Polyakov monopoles etc.
Oct
31
comment Magnetic monopole bound state
I think you're being pedantic by discussing duality transformations. There is no actual ambiguity in what we call "electricity" and "magnetism", because there is a universally-accepted convention that resolves the ambiguity. Every physicist agrees: Electrons have an electric charge, and my refrigerator has magnets on it, not the other way around.
Oct
29
comment Polarization of Light Without Reducing Intensity
I don't get that paper. If the two polarizations get sent to the same direction, then it violates thermodynamics and the paper is wrong. If they get sent to different directions, why not just use a beamsplitter cube and a half-wave-plate and some mirrors to accomplish the same thing with >99% efficiency? I don't see a clear discussion of this in the paper.
Oct
16
comment Non-uniqueness of the k-vector in Bloch state
I made a wikipedia image on this topic: commons.wikimedia.org/wiki/File:BlochWaves1D.svg See the caption too. Does that help? If not, what's confusing about it?
Oct
9
comment Polarization of Light Without Reducing Intensity
If you combine a horizontally and vertically polarized beam using a beamsplitter, you can with linear polarization, or circular ... or unpolarized! How do you propose to avoid winding up in the same unpolarized situation you started in?
Oct
2
comment Polarization of Light Without Reducing Intensity
Yes, that's exactly right!
Sep
29
comment Do photons emitted from a LED show bunching?
Yes, if you have a giant LED but you ONLY look at the 0.1% of photons that are coming out from a particular part of the chip and/or coming out in a particular direction ... then that subset of the photons can have bunching or anti-bunching.
Sep
17
comment How does DC current work in Cathodic Protection?
I would say that the important thing is the DC voltage, not the DC current. The voltage prevents corrosion, the current is an inevitable side effect of applying a voltage.
Sep
13
comment What is the pressure of a charged gas?
@BlackbodyBlacklight - The "novelty glass globes filled with fluorescent plasma" is not an example. Even if it were completely ionized, it would be a mixture of positive and negative ions.
Sep
11
comment Order of magnitude for the range of vision
I don't understand "eye can't reach". We can easily see stars trillions of miles away.
Sep
4
comment Silicon parabolic dispersion for X minima
"Assuming the six equivalent bands are ... spherical" ... but they aren't. The energy rises more sharply in some directions than others.