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Mar
18
comment What experiments compete with BICEP 2, and when are their results expected?
@innisfree: The quote above, from the BICEP paper, shows that BICEP acknowledges tension with other experiments and doesn't currently have a resolution.
Mar
18
comment What experiments compete with BICEP 2, and when are their results expected?
@innisfree: I don't get it: your model would be disproved by the measurements. Are you saying that Planck and/or BICEP2 are misinterpreting their data? That makes sense, but the fact remains that they are now claiming results for r that don't appear to be consistent. That's the tension that needs to be resolved.
Mar
18
comment What experiments compete with BICEP 2, and when are their results expected?
@innisfree: Both experiments reported their results in terms of the same parameter (r), and those results disagree.
Mar
18
comment What experiments compete with BICEP 2, and when are their results expected?
This "most likely" value of r is barely consistent with Planck's upper bound. (Why didn't they report it as the headline number?)
Mar
18
comment What experiments compete with BICEP 2, and when are their results expected?
These high values of r are in apparent tension with previous indirect limits based on temperature measurements and we have discussed some possible resolutions including modifications of the initial scalar perturbation spectrum such as running. However we emphasize that we do not claim to know what the resolution is."
Mar
18
comment What experiments compete with BICEP 2, and when are their results expected?
"Subtracting the various dust models and re-deriving the r constraint still results in high significance of detection. For the model which is perhaps the most likely to be close to reality (DDM2 cross) the maximum likelihood value shifts to r = 0.16 +0.06 -0.05 with r = 0 disfavored at 5.9σ.
Mar
18
comment What experiments compete with BICEP 2, and when are their results expected?
@DavePhD: Interesting. This portion of the conclusion of the BICEP2 "Detection" paper acknowledges the "tension":
Mar
17
comment What was the major discovery on gravitational waves made March 17th, 2014, in the BICEP2 experiment?
Related: resonaances.blogspot.com/2014/03/curly-impressions.html
Mar
13
comment Capacitor in series?
In your figure, the conductors are the wires, plus plates C and D. (But if plates A and B were not identical, they would also break the symmetry.)
Mar
13
comment Capacitor in series?
The geometry includes the sizes of the various conductors, their locations, and their arrangements.
Mar
13
comment Why do both plates of a capacitor have the same charge?
related: physics.stackexchange.com/questions/101116/…
Mar
13
comment Capacitor in series?
I've updated my answer.
Mar
10
comment electron levels in a high voltage conductor
@Potatoswatter: I've changed my language from "negligible"; thanks for point that out.
Mar
10
comment electron levels in a high voltage conductor
@Potatoswatter: See the "Configurations" section of the Wikipedia article on High-voltage direct current, where all these configurations are described. Also ref the "Single-wire earth return" article. (By the way, a +/-150kV cable still has 300kV between the conductors.)
Mar
10
comment electron levels in a high voltage conductor
@Potatoswatter: Of course there is a return power line, which could be the earth, another cable, or a coaxial element around the high voltage cable. I don't understand your concern.
Mar
6
comment Capacitor with different charges on each plate
Thanks, but my objection is to the formula at the end of your third paragraph, which is true for a parallel plate configuration but is not true in general, and in particular is not true for the geometries mentioned in the question. I've edited my answer to make this point more explicit.
Mar
1
comment Capacitor with different charges on each plate
@suresh: got it, thanks! I've edited my answer.
Feb
28
comment Capacitor with different charges on each plate
I think this answer is incorrect. For the coaxial capacitor in the question, the electric field between the two conductors is determined by the inner conductor's charge only, which then determines the potential difference. The "excess" charge of the outer conductor produces an external field which must terminate somewhere else.
Feb
6
comment Euler-Lagrange equations and friction forces
But, but, but, but... Ah, I thought item 3) was possible, but I see now why it doesn't work. Sorry for the bother...
Feb
6
comment Euler-Lagrange equations and friction forces
It seems to me there is a conflict between your answer to your linked question (#20929) and Professor Moretti's "frictional" Lagrangian here, which can be written as kinetic energy minus a time- and velocity-dependent potential. I suspect the explicit time dependence is at the root of the matter. Thoughts? Thx.