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Dec
29
comment Why are electromagnetic waves not able to pass through a hole with a diameter smaller than the wavelength?
But if they are close together...closer than the wavelength of the radiation...then they represent two coherent sources whose amplitudes add. So you get FOUR times the power. Diameter-to-the-fourth. (Because it doesn't matter if the two holes are merged into one.) Two mistakes here. (1) Two holes side by side do not constitute a hole with twice the diameter. (2) If power goes like the fourth power of the diameter, and you double the diameter, then you get 16 times the power, not four times. For a correct explanation of the exponent, see the questions that this question duplicates.
Dec
27
revised Why are electromagnetic waves not able to pass through a hole with a diameter smaller than the wavelength?
remove quantum-mechanics tag; add diffraction
Dec
27
comment Why are electromagnetic waves not able to pass through a hole with a diameter smaller than the wavelength?
duplicate of physics.stackexchange.com/q/141556 and physics.stackexchange.com/q/141562
Dec
22
awarded  Necromancer
Dec
15
awarded  Popular Question
Dec
7
comment Has relativity of simultaneity been directly observed?
[...] test theory, which is provided by the SME of Colladay and Kostelecky, arxiv.org/abs/hep-ph/9809521 . A vast amount of data has tightly constrained the Lorentz-violating parameters of the SME: arxiv.org/abs/0801.0287
Dec
7
comment Has relativity of simultaneity been directly observed?
[...] simultaneity becomes absolute in that sense. That doesn't mean that the many tests of the relativity of simultaneity become invalidated. We've experimentally verified that different observers get different results when they carry out synchronization. A preferred frame would just tell us that one privileged observer's result was preferred. Furthermore, RMS is purely a kinematic theory, and therefore its parameters would be specific to a certain measuring device, such as a specific kind of clock. Null results from clock-comparison experiments tell us that we really need a dynamical [...]
Dec
7
comment Has relativity of simultaneity been directly observed?
This is a misinterpretation both of the RMS test theory and of this type of test theory in general. In the current fundamental theories of physics, Lorentz invariance is taken to be exact, and that means that regardless of the precision with which we can verify LI, it is still vulnerable to falsification by a later, more precise experiment. Any such hypothetical future falsification of LI would presumably lead to the existence of a preferred frame, since LI is mainly a statement of the nonexistence of preferred frames. Given a preferred frame, we have a preferred time coordinate, and [...]
Nov
26
awarded  Good Question
Nov
26
awarded  Enlightened
Nov
26
awarded  Nice Answer
Nov
25
awarded  Nice Answer
Nov
24
awarded  Nice Answer
Nov
22
comment Would a wormhole in space look like anything at all?
@GreenAsJade: Intense radiation inside the wormhole is a standard prediction. I don't know enough about QFT on a curved background to be able to give you a clear explanation.
Nov
21
comment Would a wormhole in space look like anything at all?
What you're saying makes sense to me. I would also probably expect a wormhole to emit a lot of nasty ionizing radiation, since that's what's normally expected to destroy objects passing through.
Nov
21
revised Poynting vector plane wave
spelling
Nov
21
comment Definition of the quality $(Q)$ factor?
Why the downvote?
Nov
21
comment How far has a 13.7 billion year old photon travelled
@PetTaxi: The proper length is zero, because the photon's path is lightlike. If you want to define the photon's "odometer," you can't do it in the photon's frame, because a photon doesn't have a rest frame. The 13.7 byr is measured on a clock that's at rest relative to the Hubble flow. The 13.7 blyr is measured on a chain of rulers, each at rest relative to the Hubble flow.
Nov
21
answered Definition of the quality $(Q)$ factor?
Nov
21
comment Do consciousnesses get “scattered” across the many worlds of the MWI?
MWI doesn't really have branching. physics.stackexchange.com/questions/32501/… . MWI just says there's a wavefunction, and it evolves unitarily. Branching may be an appropriate, approximate description in some cases.