40,229 reputation
355127
bio website inspirehep.net/…
location Duchy of Grand Fenwick
age 44
visits member for 4 years, 6 months
seen 11 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.


May
19
comment Why is the partition function divided by $(h^{3N} N!)$?
I think there are two distinct answers here. One for the factor of $h^{3N}$ and one for the $N!$. With that knowledge can you deduce the origin of either? Or is the question really about both?
May
19
comment Can one detect cosmic ray muons with a DSLR camera?
Recombination photons are emitted into all $4\pi$ steradians of solid angle. You can more or less ignore them because (a) most will miss the detector and (b) those that do hit will have the registered position very weakly correlated with the emitted position (i.e. probability goes by $1/r^2$ and no other dependence). Full coverage calorimeters like KamLAND or Super-K could in principle get some use out of them, but they are swamped with the intended signals (scintillation or Cerenkov).
May
19
revised Is it feasible to measure the energy of cosmic ray muons with a consumer Digital Single Lens Reflex camera?
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May
19
comment Can one detect cosmic ray muons with a DSLR camera?
I have updated my answer to the early question detailing the progress of my students work. @Count: I'm not sure why you are expecting straight features in your data. You expect (1) point-like features where the muon actually excites the focal plane directly and (optically distorted, pixelated and sparse) annuli where Cerenkov light intersects the detector plane; if the detector comes all the way to the surface of the detector you expect a disk. So yes, a DICH detector. Or if you take note that the detector is Barely able to detect the signal a ... ::cough:: Uhm, yeah.
May
19
revised Is it feasible to measure the energy of cosmic ray muons with a consumer Digital Single Lens Reflex camera?
added 1679 characters in body
May
19
revised Is it feasible to measure the energy of cosmic ray muons with a consumer Digital Single Lens Reflex camera?
added 1679 characters in body
May
18
comment Can Lagrangian mechanics be justified without referring to Newtonian mechanics?
I think that @CuriousOne's point is one that should be emphasized over and over and over again (three times just for Daniel's benefit, natch): that giving the right answer plus a degree of parsimony is all the justification that a scientific theory needs. Ever. At all. And while the OP may not be confused about that the current state of the title is just dreadful.
May
18
comment Work = Force x Distance vs Displacement
"(the direction of F reverses after the first 10 m" @lemon. That really depends on the nature of the force for which the work is being calculated, so you should not make blanket statements like that.
May
17
comment How do waves have momentum?
It is possibly easier to grasp if you think about the momentum transfered by the coupling between elements of a wave medium. Of course that leaves of worrying over how it works in an electromagnetic wave.
May
16
comment Bending moment of a cantilever beam
Let me rephrase. What is a typical value of $E$ for a modest strength, day-to-day material. How does that compare to what you have computed for pasta?
May
16
comment Bending moment of a cantilever beam
Have you looked at many tables of the Young's modulus? Note the units typically used to tabulate these moduli. How sure are you that this value is actually large?
May
16
comment How can a wave travel if it is spread over all space?
This pretty good answer would benefit from more emphasis on the notion that some real cases (like $r \gg \lambda$) being good approximations to plane waves and less on what configurations are really real. But bringing the subject up at all is important.
May
16
comment Would passing horizontally polarized light through a varying width vertical slit allow you to measure the amplitude of light?
My earlier comment was directed in particular at the notion of a relationship between frequency and amplitude, as you note there is a relationship between energy density and amplitude, but your question, but the coupling is not through frequency. But note the word density. Photons have energy, but classical waves have energy densities.
May
16
comment Would passing horizontally polarized light through a varying width vertical slit allow you to measure the amplitude of light?
@Purpose I'm too busy today to field a string of questions, but I would strongly suggest not trying to match up the classical and photon descriptions of light until you have a thorough understanding of each on its own merits. That correspondence is hard enough that elderly theorists have told me that they have only partially mastered it.
May
16
comment Would passing horizontally polarized light through a varying width vertical slit allow you to measure the amplitude of light?
" Wouldn't the energy or frequency of the wave also have some correlation to the amplitude?" No. Not for light, not for sound, not for waves on a string.
May
16
revised Would passing horizontally polarized light through a varying width vertical slit allow you to measure the amplitude of light?
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May
16
comment Would passing horizontally polarized light through a varying width vertical slit allow you to measure the amplitude of light?
Recall that electric and magnetic fields are vectors (have direction)? That means that two waves can have the same amplitude but different electric field orientations which is what polarization is about. Conventionally we draw the field as an arrow, giving both direction and strength, but the longer arrow does not mean that a strong field is longer in space. So the answer to your question is that classically you cannot filter different amplitude with slit width.
May
16
answered Would passing horizontally polarized light through a varying width vertical slit allow you to measure the amplitude of light?
May
14
comment Is the dimension “number of particles” a fundamental, or derived dimension (based on mass), or does it depend on the context, or is it dimensionless?
Interesting that you include temperature among the "fundamental" dimensions. Many treatments would not. Which brings us to a very basic point: systems of units are in many ways optional and elective. These kinds of question have answers about what the conventions actually used say, but they don't have answers that are unarguably correct.
May
14
comment Plasma wakefield acceleration for Protons
Note that plasma wake field mechanism are also electromagnetic in nature. They just take advantage of the non-linearity of magnetohydrodynamics to achieve stronger fields.