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458136
bio website inspirehep.net/…
location Duchy of Grand Fenwick
age 44
visits member for 4 years, 9 months
seen 6 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.


Sep
9
comment What fundamental reasons imply quantization?
@AlfredCentauri But normalizable wave packets can be formed from non-normalizable planewave solutions. As they are linear combinations of solutions they are also solutions. So at least for the free particle I should have a continuum of normalizable solutions. See the discussion around line 2.83 in Griffiths or in most any other intro text. It is harder to show in closed form for other unbound cases, but just this one messes with a simple assignment of bound == normalizable; unbound == not-normalizable.
Sep
9
comment What fundamental reasons imply quantization?
I don't think you get quantization from the Schrödinger equation without a bound state. The spectrum of free particles is continuous. In field theory there is quantization of the occupation number of each (often continuous) state, but that is a different thing.
Sep
8
comment Is coherent light required for interference in Young's double slit experiment?
That said, in interferometric experiments (like the two slit job) you get results that are easy to interpret if you have a monochromatic source. Broadband sources will result in complicated multicolored figures on the projection screen which then require more careful analysis and explanation.
Sep
8
comment Is coherent light required for interference in Young's double slit experiment?
I'm with @Ben on this. Monochromaticity and coherence are different things. Lasers are monochromatic (except the ultra-short pulsed ones) and coherent. Raw sunlight is neither. The light from a sodium vapor lamp is fairly monochromatic but not coherent. Light from a broadband source that has been passed through two pinholes in series is polychromatic and coherent.
Sep
8
revised Controlling Neutrinos for Communication
typo fixes
Sep
8
comment Achieving almost the speed of light
The magnets have nothing to do with accelerating the protons or ions (which is done with microwaves), but rather with keeping the beam bending around in a circle so that the klystrons (the microwave cavities where the acceleration happens) can be used many times on each proton. Momentum is determined by the bending radius of the beam in the magnetic fields, and combined with know the mass of the beam particles gives velocity. Of course, velocity is a figure no one bothers to calculate except when writing a press release: particle physicists stick with momentum and energy whenever possible.
Sep
7
comment Does physics address the topic of consciousness?
"the Copenhagen interpretation ascribes a special role to observers and measurement processes" Absolutely the dumbest idea that just won't go away in all of science, too. That was Schrödinger's whole point with the cat gedankenexperiment. What this implies about Penrose (often a brilliant guy) is left as an exercise for the reader.
Sep
7
comment Rate of evaporation of water
"Are there any theories/models that explain this quantitatively?" Of course there are. They live mostly in thermodynamics and statistical mechanics, but they are complicated by the fact that many of the ill-specified "things" you probably care about have a lot of structure. Phase change physics is fun. Or at least if can be if you come properly equipped.
Sep
7
comment Does physics address the topic of consciousness?
Step one: define "consciousness" in terms of physical observables. Once you've done that we'll get to work on it.
Sep
7
awarded  Announcer
Sep
7
comment Is it possible that the force due to gravity varies based on density?
"although Newton's gravitational force equation leaves out any notion of density or size" Isn't really true at all. Though usually exhibited in a point-mass form, Newton's gravity can be (and routinely is) worked in integral form that does exactly take into account the distribution of mass in extended bodies.
Sep
7
comment Neutrino power plant
I'm concerned that the question violates the "fictional physics" constraint. Above the Z mass, neutrinos do interact strongly matter, but that is uninteresting for the purposes of this question because the main neutrino flux through the Earth is at solar energies (which, like reactor energies are a few MeV). The cross-section there is low for very fundamental reasons relating to the mass of the weak bosons and the Fermi coupling constant.
Sep
7
comment Neutrino power plant
@DeerHunter Well, reactor neutrinos are not "high energy" in the usual terminology. They are typically a few MeV.
Sep
7
comment Controlling Neutrinos for Communication
@twistor59 Nawh. That's not the way to think of it. Think, instead of ultra-wide band. It is pulses in time space. Like WiFi, only without the selection of bands.
Sep
7
answered Controlling Neutrinos for Communication
Sep
7
comment Controlling Neutrinos for Communication
Related: Microsecond trading with neutrinos .
Sep
7
comment What is Verlinde's statistical description of gravity as an entropic force?
How does this differ from your earlier question on the same topic?
Sep
7
comment What is Verlinde's statistical description of gravity as an entropic force?
Probably also worth reading the comments on an earlier question here on Physics.SE.
Sep
7
comment What is Verlinde's statistical description of gravity as an entropic force?
In what ways does the wikipedia page on the topic (from whence you got that figure, which you have not credited) fail to answer your question. Have you looked at the references wikipedia cites?
Sep
6
comment Special relativity and massless particles
@joshphysics Now that one, I can handle. The relationship between energy, momentum and mass rises out of the transformation properties of the energy and momentum, and while we found those from the explicit forms for massive particles the transformation properties must hold for any other form as well.