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Nov
19
comment Anti-matter as matter going backwards in time? (requesting further clarification upon a previous post)
It's dissipative from the forward-time perspective, but from the reverse perspective it's anti-dissipative (I just made that word up). Energy is still conserved, but from its perspective the time-reverse-positron is gaining energy from the fluid, because the second law is time-reversed, which it has to be, just like everything else. (If it wasn't then it would be reversed from our perspective, which would definitely be bad.) From our perspective the positron still loses energy, of course.
Nov
19
comment Anti-matter as matter going backwards in time? (requesting further clarification upon a previous post)
that's a perfectly reasonable position, but I remain unconvinced by it. If we imagine the positron is time-reversed then from its point of view it's moving through a time-reversed fluid, and it doesn't seem unreasonable to think this would cause it to gain rather than lose energy from its perspective. I think the time-reversed interpretation should make the same experimental predictions as the forward-time one.
Nov
19
comment Anti-matter as matter going backwards in time? (requesting further clarification upon a previous post)
I'm curious: how would you expect empirical data from a backwards-travelling positron to differ from what we actually see?
Nov
19
answered Possibility for contact lenses that enhance the vibrancy of color
Nov
18
revised What is the maximum mass that the airplane can have and still maintain enough lift to fly?
edited tags
Nov
14
comment Is there a lens that would invert my vision?
@Andrew oculus rift is pretty cheap, and I think the delay can be made pretty small. I know someone who's using it for rubber hand illusion type experiments, and I would guess you need a pretty low latency for that. (I could ask him about it if that's a path you think you might take.)
Nov
14
answered Is there a lens that would invert my vision?
Nov
14
comment How many bits are encoded on the surface of the smallest black hole?
@user23660 I don't know - I know a lot about statistical mechanics and a fair bit about QM, but not much at all about general relativity. The relationship between area and entropy seems quite fundamental (holography and all that) so it would make sense if it was exact, but I'm not sure. I'll look into it.
Nov
13
comment How many bits are encoded on the surface of the smallest black hole?
@user23660 'bit' can mean two subtly different things. It can either mean a component of computer memory with two distinct states, in which case the quantum eqiuivalent is a qubit, or it can mean a unit for measuring an amount of information. In QM this latter is still called a bit, and we say that the information capacity of a qubit is one bit. It's the amount-of-information sense that I'm using here.
Nov
13
revised How many bits are encoded on the surface of the smallest black hole?
one more thing
Nov
13
revised How many bits are encoded on the surface of the smallest black hole?
added some more stuff
Nov
13
revised How many bits are encoded on the surface of the smallest black hole?
incorporated user10001's clarification.
Nov
13
comment How many bits are encoded on the surface of the smallest black hole?
@user10001 many thanks for the clarification!
Nov
13
comment How many bits are encoded on the surface of the smallest black hole?
@Danu there are still some choices you have to make in defining them, since it depends which constants you consider the most fundamental. If I consider the ratio of black hole entropy to surface area to be an important fundamental constant, I will want to set it to one, at the expense of setting some other constant to something other than 1. It is, of course, fairly pointless to argue about which constants are the most fundamental, since this is purely a matter of taste.
Nov
13
answered How many bits are encoded on the surface of the smallest black hole?
Nov
13
comment Do the particles made in a collider exist outside the collider?
@AlfredCentauri I think Zeynel is using "electric and magnetic fields" to mean "electric and magnetic fields of a very high intensity, as found inside a collider." In that case it makes perfect sense to talk about turning them off.
Nov
13
comment How many bits are encoded on the surface of the smallest black hole?
I think the assumption of Euclidean geometry will be violated in quite an extreme way, because a tiny black hole will be a very highly curved region of space-time. My own wild guess is that the smallest black hole will have an entropy of one bit, and therefore a surface area of four Planck areas -- but I have no idea if that is correct. It's an interesting question: +1.
Nov
13
revised Motivation for the use of Tsallis entropy
corrected error, changed title, made small improvement.
Nov
13
comment One way insulation?
To concur and clarify slightly: it's the second law of thermodynamics (increasing entropy) that would be violated, not the first law (conservation of energy). You could use it to build a "perpetual motion machine of the second kind", which converts heat at a single temperature into usable energy, but not a "perpetual motion machine of the first kind", which creates energy from nothing.
Nov
13
asked Motivation for the use of Tsallis entropy