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"I would never die for my beliefs because I might be wrong."

-- Bertrand Russell


Mar
30
comment First-order wave equation: Why is its presence not common?
The Dirac equation is a first order wave equation.
Mar
16
comment Quantum Wave Mechanics
If something satisfying a wave equation is not a wave, then what is? This is not a physics question but a semantics discussion.
Mar
14
comment Superconducting loop as a particle detector?
en.wikipedia.org/wiki/Cryogenic_particle_detectors
Mar
5
comment Does limit $\hbar \rightarrow 0$ in Quantum Mechanics mean anything?
@Lubos: yes of course, lapsus.
Mar
5
comment Does limit $\hbar \rightarrow 0$ in Quantum Mechanics mean anything?
Non-relativistic limits are limits with $c \to 0$, not $\hbar \to 0$.
Feb
25
comment What's wrong with this faster-than-light gedankenexperiment?
I think your confusion stems from the fact you seem to think that "interference" is a quantum state. It isn't. Interference is what happens when we make a measurement that's incompatible with the state we measure.
Feb
25
comment What's wrong with this faster-than-light gedankenexperiment?
Why would Bob see an interference pattern though? Just because the particles are entangled doesn't mean that the interference experiment gets replicated on Bob's side. He still has to decide between putting a double slit down or not.
Feb
2
comment Would not gravity negate entropy?
"If gravity acts on all matter and all energy in the universe, wouldn't the universe eventually condense into pockets of energy and matter". Erm... well, if you look around you, that's actually the situation we are in. No need to wait for the heat death of the universe.
Feb
1
comment Can light be launched outwards from an event horizon?
Read up on lightcones a bit first, the last picture shows what happens in the black hole case. If that doesn't answer your question yet, I'll try to write a full reply.
Feb
1
comment Can light be launched outwards from an event horizon?
Escape velocity is really a Newtonian concept. The event horizon is not defined in terms of escape velocity, but rather as the boundary of a region beyond which the outside world can not be affected anymore. Another way to express this is by looking at what happens with light cones in the geometry of a black hole. As you get closer to the whole, the future light cone tips towards the black hole. On the event horizon, it lies completely inside the boundary.
Feb
1
comment Can light be launched outwards from an event horizon?
The thing is, once you're on the horizon, there does not exist an "outward" direction anymore.
Jan
31
comment About Boltzmann H-theorem
Could you specifically reference the derivation you mention. The assumptions should be in there. But just out of the top of my head, you're going to have to assume some specific initial conditions (they have to be "typical"). The way Boltzmann did it was with the Stosszahlansatz. But more modern derivations use more explicit assumptions on the initial conditions.
Jan
20
comment According to relativity, can a statement be true and false in same time?
What has relativity to do with it? If Newton wrote "It's 1766." and you read the statement now, does that make the statement false or true?
Dec
24
comment Is that true that neutron activity on Earth in 2013 is unusual?
Just skimming through the topics on that website, I'd take anything coming from there with a pinch of salt. Has it been published in a peer-reviewed journal?
Dec
7
comment Electron double slit experiment and the electric field
The field will interfere too, and in such a way that you won't be able to tell, from measuring it, through which slit the electron went.
Nov
12
awarded  Yearling
Oct
28
awarded  Nice Answer
Oct
19
awarded  Taxonomist
Jul
29
comment Why terminal velocity exists?
@ZoltánSchmidt: You seem to be confused by something else as well. A body can keep accelerating while never reaching the speed of light. See Rindler coordinates.
Jul
14
comment Education : Students devising and solving their own problems
@udiboy: note it was only a critique for discouraging own investigations. As you'll note, I pretty much give the same suggestions as you do.