38,934 reputation
354126
bio website inspirehep.net/…
location Duchy of Grand Fenwick
age 44
visits member for 4 years, 5 months
seen 9 hours ago

Experimental nuclear and particle physicist. These days I'm teaching, but I've spent a lot of time on nucleon structure in fixed target electron scattering and neutrino oscillations using reactors and beam sources.

Been reading Zemansky & Dittman's book on thermodynamics recently. Quote: ``The concept of temperature is rich in interpretations and levels of abstraction.'' Nice.


13h
answered Where would the dark matter particle fit inside a picture of the standard model?
13h
comment What is the meaning of “ Ψ is not a measurable quantity in itself”?
I'm a little confused by the question, that sentence means exactly what it says: you can't measure $\psi$. Did you expect that it was hiding something more subtle?
13h
comment Does the Advanced Photon Source use electrons or positrons?
The reason for preferring electrons would almost certainly be current. Capturing and cooling large number of positrons is challenging, which presumably limits the currents that can be achieved. Electrons, on the other hand, are plentiful. (And the APS uses some insane currents by usual accelerator standards.)
1d
comment Is it possible to generate energy by the moon orbit?
See also: physics.stackexchange.com/questions/6400/… physics.stackexchange.com/questions/9290/…
1d
comment Can we find the exponential radioactive decay formula from first principles?
I think this answer could use some expansion as it is currently barely more than a link. That said, the abstract is very interesting; two decay channels implies two time scales and the possibility of beats that can be detected even at long periods if the system is coherent. Next question: is a macroscopic sample coherent? I don't really see how it would be, but I'm also getting ever further out of my depth.
1d
comment Is the planet Mesklin as described in Hal Clement's Mission of Gravity correct?
"The downward force felt by a person standing on the surface is the same everywhere." Is incorrect. The potential is the same everywhere on the surface, but there is no requirement that the local gravitation have the same strength.
1d
comment Can we find the exponential radioactive decay formula from first principles?
I don't know of an example, but I would argue that it's almost unavoidable in a unstably bound quantum system with a substantial halflife: the decay results from a small perturbation on a otherwise stationary state.
1d
comment Can we find the exponential radioactive decay formula from first principles?
Anything which gives you a constant probability per nucleus gives the result immediately. A standard lab is to roll dice, discarding those that show a 1.
2d
comment Charles Law inverse for cooling?
There are some condition that must be met for this to hold. Free expansion won't do it.
2d
comment How to simulate pendulum movement with high amplitude
The point of simulation isn't to simply apply a closed form solution (what you are trying to do), but to allow you to do without this elusive beast and work from the easily found equation of motion. Convert the EoM (a differential equation) to an appropriately chosen difference equation approximation and go to town.
2d
answered Is every aspect (fundamental forces, periodic table) of an antimatter universe exactly the same, except the fact that it's all antimatter?
2d
comment Is the planet Mesklin as described in Hal Clement's Mission of Gravity correct?
@TimB As I read it the answer about the non-linear deformation tells us that the planet in Mission of Gravity simply can't exist. So the computations therein are intrinsically wrong. But I didn't wield the big mod stick to close because I am open to other interpretations.
2d
comment Can I say that physical entities do not exist and everything is observed “as if” they exist?
You need a little more rep, but you can try chat. Even without the philosophy, however, you'd be out of luck on the main site if discussion is what you want. We do question and answer.
2d
comment Is the planet Mesklin as described in Hal Clement's Mission of Gravity correct?
Effectively a duplicate of physics.stackexchange.com/questions/10670/…, I think.
Apr
22
revised What would happen to electronic circuits when traveling near the speed of light?
remove self-promotional material
Apr
22
comment What would happen to electronic circuits when traveling near the speed of light?
The link is clearly advertizing a personal theory in violation of site policy on this topic, so I am going to remove it. (I should also mention that hiding a link to your own blog behind a URL obscurer is not doing you any favor in terms of the reception you'll receive here.) The rest of the answer is fairly incomplete and will likely continue to accumulate downvotes unless improved.
Apr
22
comment Fastest converging series of resistors
This question may well be on topic here, but it might get more responses on Electrical Engineering. Let me know if you want me to inquire with the mods over there.
Apr
22
comment True randomness via Radioactive decay
The standard algorithm is to compare the time between decays (c) and (b) with that between (b) and (a). $t_{cb} > t_{ab}$ implies one value for your bit, the other sense the other. Discard any that are too close to call or any triplets featuring one or more times near your resolution.
Apr
22
comment Physical reality of calculated wavelength from two measurable phenomena slit distance and fringes distance?
Huygen's principle does explain fringes behind a single edge. See for instance Fowles Introduction to Modern Optics figure 5.25. The math is harry enough to want to do it by Fourier's methods. Water will do it too, though it is experimentally difficult to set up.
Apr
22
comment Physical reality of calculated wavelength from two measurable phenomena slit distance and fringes distance?
Huygens principle. Huygens principle. Huygens principle. All of your questions---All of them---are answered by the application of Huygens principle. Students often resist this, thinking that various heuristics are "easier", but sooner or later they have to learn the underlying tool.