Recent content by vsv86

I think all the previous answers are good, but there is one tiny bit that I think has been missed - the evanescent waves (https://en.wikipedia.org/wiki/Evanescent_field). The point is that even if you had no dust between your detectors and the distant object, and if you had perfect optics, and...

How about we try to define a reference frame? I will not try to be rigrous here, but merely gather the things I think are necessary for this concept. Nothwithstanding my previous digression (I agree it was a digression - my bad) to relativity, in Newtonian mechanics we can define a reference...

I am not entirely sure, but I think you have discovered the difference between phase and group velocities of the free electron.And, they are different. Griffiths has a great section on this (Griffiths "Introduction to Quantum Mechanics", Sec 2.4, Eq. 2.90). Before proceeding you must tell us...

I think one should be cautios here. As is pointed out in MTW "Gravitation" (6.3) the accelerated reference frame is a local thing - it does not cover the whole space. What does it mean? Well, according to my back-of-the-envelope calculation, if you were to stand at the front of the rocket of...

What helped me with these sorts of things, is getting a book on linear and multi-linear algebra and reading about tensor product (direct product). You have 2 two-dimensional vector spaces (##V,W##), both over complex numbers. You then create another vector space ##V\otimes W## out of these two...

My interest in quantum theory is mostly on amateur level, so forgive my ignorance, but are there many cases where entanglement is important outside the quantum communications and building quantum computers? What I mean is that, if I was doing computations on response of solid-state, or molecular...

You would need to find the electric field (##\vec{E}##) due to changing magnetic field (by solving Maxwell's Equations), and then compute the voltage across the open loop ##C## by integrating the electric field along it ##V=-\int_C \vec{E}.\vec{\hat{l}} dl##

Of course. The initial question talked about the Biot-Savart law which only applies in magneto-statics (one must use Jefimenko's equations or equivalent in electrodynamics), so I talked about magnetostatics. In case of full electrodynamics, one will have the extra term due to displacement...

@Dale sorry, I did not tag you, still getting used to forum :-)

I agree with Dale. When applying integral form of Ampere's law remember that the requirement on the surface bounded by the imaginary loop you draw around the current line, the loop that you use to get your magnetic field, is only that this surface is bounded by the loop. So I could deform this...

Thanks physguy and Hypercube!

Hello I am planning to apply for some academic positions (lecturer, assistant professor level and equivalent) in US, Canada and Australia. My field is nano-optics and applied electrodynamics. Can anyone suggest websites where such positions would be advertised? I have googled of course. I get...

OK, the TC seems to be gone. I will finish what I have started just in case someone else needs it. In the last topic I have shown that the current density due to a single current loops is the curl of the delta function. Now, a torus is essentially a loop of magnetization, and magnetization is...

That's the thing. I don't have a book context, and I would like to have one, but from a book on maths if possible. What I have is a suggestion from a colleague that a phenomenon I am looking at may be linked to magnetic Skyrmions by analogy (he cannot give any more information on this). I found...

Hello I was playing with maths for magnetic Skyrmions. There is very prominent mathematical construct in there that I would like to understand, but I do not know where to look. It is easiest to state it for simple 2d space. We can define a 1-form: ##\omega=\sqrt{\left| g \right|}...