77,406 reputation
178166
bio website ratsauce.co.uk
location Chester, United Kingdom
age 53
visits member for 3 years, 3 months
seen 4 hours ago

Semi retired old time computer nerd who started programming on a Commodore Pet.

Since I'm also active in the Physics forum I should add that I started as a theoretical chemist, moved into solid state photochemistry and finally worked in industry as a colloid scientist. I only became a full time computer nerd in 1997.


Aug
16
comment No magnetic dipole moment for photon
researchgate.net/publication/…
Aug
16
comment localization of wave or particles
Aha, I've just followed the link in your comment and it's an article about solitons and instantons. "Localised" simply means the solution is non-zero over a finite (usually small) region of space. Normally this would be applied only to a wave like solution localised in space, rather than e.g. a hydrogen atom that is certainly localised in space but not a wave like solution.
Aug
16
comment localization of wave or particles
@Raisa - have a read through the Wikipedia article on solitons and see if that helps. In QFT there are also instantons that are localised in both space and time.
Aug
15
comment Physical significance of getting an non-integrable function in an equation
I think the first part of your answer is really about singularities in physics rather than non-integrable functions.
Aug
15
comment Why are diffraction gratings not called interference gratings?
"And the double slit experiment doesn't talk about diffraction" - see for example en.wikipedia.org/wiki/…
Aug
15
comment Would it be possible to build a Solar Panel Etalon?
Oops, that's a mistake - how I managed to turn absorbs two thirds into reflects two thirds I don't know.
Aug
15
comment X-ray and neutron powder diffraction: peak broadening due to crystal size
@SRJ: I've extended my answer to (I hope) make it clearer what the physical origin is.
Aug
14
comment What is the difference between air pressure and atmospheric pressure?
Atmospheric pressure decreases, not increases, with altitude
Aug
13
comment Quantization of Electron Spin
Are you asking why angular momentum is quantised, or why the electron has a angular momentum of 1/2?
Aug
8
comment Is diffraction through an aperture similar to diffraction by a plane of atoms?
The diffraction pattern is approximately the Fourier Transform of the plane of atoms. Crystals behave as approximately sinusoidal gratings, so the FT gives sharp spots. If you change the X-ray transmission to be opaque triangular atoms with 100% transmission between them you just need to do a 2D FT of this to find out what the diffraction pattern would look like. Offhand I don't know what the difference would be, but you could easily do the Fourier Transform to find out.
Aug
5
comment Fourier transformation, electric field and magnetic field to have a shielding lattice against particles
Yes, but the convergence for a delta function is very poor because the coefficients in the Fourier expansion are constant i.e. they do not decrease as the frequency of the sine wave increases. What I can do is reduce the width of the gaussian to make it very narrow. However if I start posting more and more graphs here we're going to annoy people. I suggest that I tidy up the spreadsheet that I wrote to do the calculation and you can take a copy of it to play with.
Aug
5
comment Fourier transformation, electric field and magnetic field to have a shielding lattice against particles
Note that a gaussian is a fairly easy function to fit. If you chose a different function this would affect the number of terms required. If you choose a function with discontinuities, or discontinuities in the gradient, it will take a large number of terms to get the error small at the discontinuity.
Aug
5
comment Fourier transformation, electric field and magnetic field to have a shielding lattice against particles
With 10 terms the maximum is 1.8% (at the peak). To get less than 0.1% difference requires only 15 terms.
Aug
2
comment Relativity - Lorentz transformation
The derivation isn't hard, but it's somewhat tedious. If you Google for "derive lorentz transformation from metric" there's an article at physicsinsights.org/derive_lorentz.html that goes through it.
Jul
31
comment Is there any theory for origination of charge?
Mass and charge are not both intrinsic properties. Charge is an intrinsic property but mass isn't. Above the electroweak transition the mass of all fundamental particles goes to zero but the charge is unchanged.
Jul
31
comment Using Thrust from Air Pressure
1/4 inch diameter? If so the area is only 0.05 square inches.
Jul
31
comment How can the quantum state of the universe decohere
You'll have to define what you mean by the quantum state of the universe. I wish you luck - no-one else knows what it means or even if the concept makes sense.
Jul
30
comment What led to the electroweak and strong forces splitting?
SSB is definitely the reason for electroweak symmetry breaking and a probable mechanism for electroweakstrong symmetry breaking as well. The details of the breaking mechanism are different in the two cases, but the idea is broadly the same. However take this with a large pinch of salt as neither SU(5) nor SO(10) give an adequate description of the real world.
Jul
28
comment Why does a dielectric have a frequency dependent resistivity?
Carlos: sorry, I completely misread your question. Please disregard my comment. I've removed my duplicate flag.
Jul
25
comment Hooke's law doesn't work well with my spring?
As Vasiliy says, it looks as if the spring has been made so it's under tension i.e. there is a force holding the coils together. You'll need to add a certain weight to conteract this tension before the spring starts extending, but once you've added that weight you should find the weight:extension is linear.