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Mar
20
comment Can or does the Casimir effect play a role in solving the electron self-energy problem?
@JánLalinský, I think the issue is not the introduction of substructure, but just the consistency of a point-like electron that has no well-defined mathematical limit.
Mar
18
comment Can or does the Casimir effect play a role in solving the electron self-energy problem?
@JánLalinský, I tend to think it is a problem given that Feynman dedicates a few pages to it in his Feynman Lectures and seems genuinely perplexed by it.
Mar
17
revised Can or does the Casimir effect play a role in solving the electron self-energy problem?
added link to a related question
Mar
17
comment Can or does the Casimir effect play a role in solving the electron self-energy problem?
@JánLalinský, maybe you aren't familiar with the classical problem of electron self-energy? I agree with your statements, but I think that normally you would consider how much energy it takes to "assemble" the electron. Even though the electron is considered elementary, there is no explanation for what "holds it together."
Mar
17
asked Can or does the Casimir effect play a role in solving the electron self-energy problem?
Mar
13
comment Are quantum decoherence and Everettian approaches to the measurement problem necessarily distinct?
My problem is that your last sentence seems directly at odds with assuming reality of the universal wave function. I don't see how you can maintain both pictures simultaneously.
Mar
7
awarded  Favorite Question
Feb
7
comment Twin Paradox - different approaches
@John Rennie, the point is that without the equivalence principle the traveling twin has no way of knowing whether she is following a geodesic or not, despite feeling herself accelerate. The acceleration could be because the pilot fired engines and caused a kink in her worldline, or it could be that the engines were fired in coincidence with a passing gravitation body, such that there is no kink in her worldine. Through her telescope she observes the other twin accelerate, and so depending on her interpretation of her own acceleration she can come to different conclusions about her twin.
Feb
7
comment Twin Paradox - different approaches
@John Rennie, again, just because there is one way of calculating it within SR that gives the correct answer, doesn't itself represent any evidence against an internal inconsistency. I don't have access to MTW so I don't know exactly what argument you are referring to, although I'm well aware of the "canon" that you don't need GR to solve the twin paradox. I think this canon is wrong, for reasons that I don't think are particularly difficult to understand. I would appreciate it if you could point out specifically what mistake is made by the twin in my above example.
Feb
6
comment Twin Paradox - different approaches
@joshphysics, your example is precisely what I warned against. That is, giving one solution and then calling it a day. The problem is that from the traveling twin's perspective, SR provides multiple equally valid ways of answering the question. The way of answering that I provided is not a misapplication of SR. The twin looks out his telescope and traces the arc length of the earth twin, and determines it is longer than her own. From her perspective, she has been stationary, with acceleration due to rockets used during a passing gravitating object.
Feb
6
comment Twin Paradox - different approaches
@joshphysics, note that I am NOT saying that solutions using SR do not exist. They do. But the "paradox" is in the self-contradiction of there existing other seemingly correct applications of SR in which the twins do not agree.
Feb
6
comment Twin Paradox - different approaches
It is still a "paradox" within SR because while it is "fully explainable in SR" for some methods of calculation, it is NOT for others. The picture is not self-consistent (without GR), hence, a paradox. One can see this trivially by considering that the traveling twin WILL calculate the earth-bound twin to have aged less, if she only uses SR to explain her observations. Only by noting that she is not in an inertial reference frame during acceleration does she either 1) abandon SR because it doesn't apply, or 2) use the principle of equivalence to derive that the earth twin will have aged more.
Jan
15
answered How to measure (missing) transverse energy
Jan
14
comment Double slit experiment and entanglement
I asked a very similar question here and eventually posted an answer to my own question.
Jan
13
awarded  Yearling
Dec
13
comment What are the reasons why dark matter above the TeV scale appears to be ignored experimentally?
@dmckee, it's not obvious to me that some range of ultra-TeV dark matter is inaccessible to direct detection experiments theoretically, it just seems that everyone has jumped on the GeV-scale bandwagon and we are now in a situation where we have a larger blind spot than I think is well-motivated
Dec
13
comment What are the reasons why dark matter above the TeV scale appears to be ignored experimentally?
@annav, nanoparticles is an extremely vague term when discussing dark matter, isn't it?
Dec
13
awarded  Notable Question
Dec
13
asked What are the reasons why dark matter above the TeV scale appears to be ignored experimentally?
Dec
11
comment origin of cusps in simulated dark matter halos
@astromax, then thanks for your time, but apparently you can't answer my question, which is "why" rather than simply an appeal to authority. As implied in my OP I know already that for some reason 100 particles is understood to be not enough, but nonetheless you can see cuspy behavior when integrated over time...