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Aug
25
comment Silver vs Aluminum electrodes in silicon solar cells?
You need an ohmic contact to n-Si, and an ohmic contact to p-Si. Can aluminum be both? I thought it could only be one of those (I forget which).
Aug
23
answered Does resonant inductive coupling work in the presence of a strong magnetic field?
Aug
19
comment Are there measurable quantities which directly depends on the Fermi velocity?
As soon as the Fermi level is away from the dirac point, vF has an obvious importance--density of states in particular. I guess I'm saying, it's easy to say in theory "I assume Fermi level is exactly at the dirac point", but it's not only impossible in practice, but stops being true as soon as you do something as simple as apply a voltage, even in theory.
Aug
19
comment Are there measurable quantities which directly depends on the Fermi velocity?
(1) Away from absolute zero the states above and below the fermi surface are all relevant; (2) Even with no (intentional) gating, the fermi level will not be EXACTLY at the dirac point in practice; (3) Even if it is exactly at the dirac point somewhere, it won't be exactly at the dirac point elsewhere, because of inhomogeneities like random dangling bonds in the substrate; (4) If you apply a voltage than the fermi level is tilted and cannot be at the dirac point everywhere. So again, every electronic and optoelectronic property is affected.
Aug
19
answered Are there measurable quantities which directly depends on the Fermi velocity?
Aug
6
answered Drawing the lines of force for an electric field varying in magnitude but having a constant direction
Aug
6
answered Seeking a quality plain-language description of the Wigner-Eckart theorem
Aug
6
awarded  Informed
Aug
5
awarded  Good Answer
Aug
4
revised Do all the conservation laws of Physics take no time to propagate?
add italics
Aug
4
awarded  Nice Answer
Aug
4
comment Do all the conservation laws of Physics take no time to propagate?
In my EPR pair example, there is a more energetic particle and a less energetic particle, but it is not determined which is which. If you measure the energy of one, you can immediately infer the energy of the other. But this does not require or imply that either information or energy is moving faster than light. Why would it? See physics.stackexchange.com/a/3163/3811 for more details, for example.
Aug
3
comment Do all the conservation laws of Physics take no time to propagate?
Yes, you can have two distant entangled particles (called an EPR pair), where one is more energetic and one is less energetic, but it is not determined which is which until you measure them. You can look online or in an intro QM textbook for an explanation of why information does not flow faster than light when you measure an EPR pair. This information-flow issue is commonly discussed. Well, energy also does not flow faster than light when you measure an EPR pair ... and it's for the exact same reason.
Aug
3
comment Do all the conservation laws of Physics take no time to propagate?
There is no such thing as just "continuity", there are a wide variety of "continuity equations" describing many different quantities. Energy and momentum are conserved in quantum mechanics, and yes, those conservation laws are written as continuity equations in quantum mechanics too. There is no conflict between entanglement (which is ubiquitous in QM) and these continuity equations. I'm not sure why you think there would be. Can you explain what you have in mind?
Aug
3
answered Do all the conservation laws of Physics take no time to propagate?
Aug
2
comment Is this diagram, concerning Young's double slits, inaccurate?
I added another couple paragraphs...
Aug
2
revised Is this diagram, concerning Young's double slits, inaccurate?
added 495 characters in body
Aug
2
answered Is this diagram, concerning Young's double slits, inaccurate?
Jul
31
answered Wavelength vs Wavenumber etiquette
Jul
31
comment Why is SiO2 solid while CO2 is a gas?
CO2 is based on double-bonds, O=C=O. So the heart of the question is: "Why can carbon easily form strong double (and even triple) bonds, while silicon is barely capable of forming weak double bonds?"