Reputation
4,228
Top tag
Next privilege 5,000 Rep.
Approve tag wiki edits
Badges
1 9 31
Newest
 Civic Duty
Impact
~98k people reached

  • 0 posts edited
  • 1 helpful flag
  • 305 votes cast
22h
comment The naive idea of the big bang
@CuriousOne That's not a reasonable comparison. An explosion in the conventional sense is a type of physical process for which there are models. It is completely reasonable to wonder whether the expanding universe was produced by an explosion. And I have noticed that exposition regarding this issue does not say "why primordial explosion is a physically wrong idea", it says "why big bang theory isn't a primordial explosion theory".
1d
comment Multiverse fictional constraints
Multiverse just means any scenario with more than one universe. Two is more than one, so the "theory" that reality consists of "this universe" plus "Dragonball Z" is a multiverse theory, though not a popular one outside of Dragonball fandom... As for the many-worlds interpretation of QM, that's always relative to some specific theory like "standard model + gravity"... "All logically possible worlds exist" is multiverse maximalism, found e.g. in David Lewis and Max Tegmark, and is far beyond the limited multiverse notions that are employed by some physicists.
1d
comment The naive idea of the big bang
@CuriousOne Sophistication is relative. The minimum I was after is a quantitative model based on laws or principles. The average "naive big bang theorist" is just a layperson thinking intuitively.
2d
comment Einsteins Cold Fusion and Black Holes
I don't know what "Einstein's cold fusion" is, cold fusion saga was long after his time, do you mean Bose condensation??
2d
comment Einsteins Cold Fusion and Black Holes
As for the black hole, maybe there could be some sort of magnetically driven en.m.wikipedia.org/wiki/Evaporative_cooling_(atomic_physics) in its accretion disk, under the right conditions, I don't know
2d
comment Einsteins Cold Fusion and Black Holes
en.wikipedia.org/wiki/… seems to show that the effect involves the microscopic magnetic domains inside a magnet becoming more aligned and then less aligned, in a cycle driven by external magnetic field that goes from strong to weak and back again. And in the stages of this cycle, the magnetic domains absorb or radiate energy, changing the overall temperature
2d
comment Einsteins Cold Fusion and Black Holes
I never heard of magnetic refrigeration before, but according to the Swedish link, it works because a magnetic field causes some substances to grow hotter. So you heat them with a strong field, then you make the field weaker, the magnetocaloric substance gets cooler, and so if it was touching some other substance, the other substance would get cooler too.
Feb
3
comment Can Loop Quantum Gravity and Quantum Field Theory coexist?
@John Rennie It is highly meaningful to ask about the relationship between LQG and QFT. LQG research isn't just about pure gravity, it does encompass gravity coupled to other fields. Moreover, the whole debate for and against LQG, is arguably about its relationship to QFT. So this is a completely valid question, whether or not anyone here can produce a correct answer.
Feb
2
comment Big Bang Quarks Travelling at Light Speed
@dmckee the source is right at the end, "pela"
Feb
1
comment Can Quantum Field Theory be right even though it doesn't include gravity?
otherwise, I would say that as a quantum theory of gravity, string theory is in much better shape than AS or LQG. In string theory, gravity comes automatically with fermions and gauge bosons; and in principle, the geometry and topology of the extra dimensions actually determines all the particle masses, couplings, etc. So it is quite compelling. But in practice there are a zillion possibilities and it's very hard to calculate anything. There is progress, there are partial successes, but there is so far no "standard stringy vacuum" in the way that QFT produced a "standard model".
Feb
1
comment Can Quantum Field Theory be right even though it doesn't include gravity?
@Nick the leading attempt to make gravity work as a QFT is scholarpedia.org/article/Asymptotic_Safety_in_quantum_gravity ... It has the curious claim to fame of having predicted the Higgs boson mass arxiv.org/abs/0912.0208
Jan
31
comment What effects would a finding of Gravitational Repulsion Between Matter and Anti-Matter in the ALPHA Experiment have on Mainstream Theory?
@Lewis Miller - arxiv.org/abs/1110.3054 - I have not read this paper
Jan
29
comment Venus vortex, super rotation, heat budget, plasma explosions + Pettit&Nicholson heritage: impossibilities galore. Why?
The question must be, What do you think of my theory that the conditions on Venus are the result of a bolide impact in the near past?
Jan
26
comment Why is the “expansion postulate” a postulate of quantum mechanics?
I never heard of this didactic strategy before. It seems to be a way of declaring "we won't be looking at cases where this isn't true". physics.stackexchange.com/questions/68822/…
Jan
26
comment What does $L^2(S^1,\mu_H)$ mean?
$S^1$ is a circle, a "1-sphere". So this is the space of square-integrable functions over a periodic variable.
Jan
24
comment Beyond usual quantum mechanic description of entanglement, is there any QFT or stringy formalism/explanation of it?
This is a common topic in gauge/gravity duality, e.g. see MERA, Ryu-Takayanagi. Also see "ER=EPR". i.e. don't close this question.
Jan
21
comment What effects would a finding of Gravitational Repulsion Between Matter and Anti-Matter in the ALPHA Experiment have on Mainstream Theory?
Related question: physics.stackexchange.com/questions/83378/…
Jan
13
comment Holding an electron
@user10379 in order to localize the electron (squeeze the box), some forces must keep knocking the electron back into the box. That is where the velocity uncertainty will increase, to complement the decrease in position uncertainty
Jan
11
comment Why doesn't gravity mess up the double slit experiment?
@Conifold possibly arxiv.org/abs/gr-qc/0311082 is all you would need. But as you say, the charge of the electron will affect its environment much much more than its mass. Anyway, the real answer to this question would involve density matrices, and interactions that aren't macroscopically amplified.
Jan
11
comment Does quantum mechanics play a role in the brain?
@Ross Millikan - Penrose's idea was that there is some threshold of difference in the metrics, beyond which a superposition of space-time geometries is not well-defined, and that that is when "wavefunction collapse" occurs. And the threshold is supposed to be quite subtle, so that it can come into play on mesoscopic scales.