29,819 reputation
33994
bio website inspirehep.net/…
location Duchy of Grand Fenwick
age 43
visits member for 3 years, 5 months
seen 4 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.


4h
comment Is gravitational force affected by intervening medium?
"Hence we conclude that the medium does not affect gravitational force." You conclude incorrectly, there is a buoyant force in the system now, but the weight of each object is unaffected.
6h
comment Does Contraction at High Speeds Happen in Any Dimension Besides Length?
You show how to get contraction along multiple coordinates, but still in one direction.
13h
comment Can He-4 atoms create black holes?
Some related questions: physics.stackexchange.com/questions/22049/… physics.stackexchange.com/questions/90405/… and I believe there is at least one more, but I haven't found it.
16h
comment W + jets at NLO
You'd probably be better off asking selected colleagues who know these tools rather than Physics SE. The difficulty being the level of specialization ... I'm an experimental particle physicist and I've never heard of either tool. (Because I've never done collider physics ... it's been JLAB and neutrinos for me).
19h
comment What does the Pauli Exclusion Principle say about a superposition of spin states?
@JavierBadia The consequence is that you don't have to have prepared a particular set of eigenvalues (say "up" and "down") for the occupation limit (2 electrons) to apply. This is the PEP applies no matter what games you try to play with the electron spins, as the combined wavefunction "knows" how many are allowed (in less anthromophic language, you run out of degrees of freedom to use in anti-symmetrizing it).
19h
comment Does centrifugal force exist?
The reason I have voted this down is that this answers seems to intentionally conflate inertial pseudo-forces (in this cases the effects of using a rotating frame of reference) with real forces (those that appear when you use a inertial frame of reference). It is certainly true that there are mathematical mechanisms for doing physics in non-inertial frames, but the are a complicating factor; it should be emphasized that the laws of physics have their simplest form in inertial frames.
19h
comment Is it probable that planets will stop orbiting in ellipses?
"orbiting in an ellipse or a circle is quite a coincidence - it depends on how the planet got into the solar system" Is incorrect. It follows from the form of the force law and the fact that the system is bound and nothing else.
19h
comment Relative effects of forces
"It is therefore relative, if we live in a heliocentric or geocentric system?" No. Neither the Earth nor the Sun represent an inertial frame for describing the orbits. That said the barycenter frame (which is inertial in the two body problem) very nearly coincides with the Sun's frame. And while you can work in non-inertial frames, they are not frame in which the law of nature has simple form.
1d
comment Looking for the name of a physical phenomenon in fluids' mechanics
@Mehdi The sixty degree assumption makes the vector difference easy. If both the velocities are the same magnitude, then the difference has that same magnitude (think equilateral triangle).
1d
comment Jet taking off from an aircraft carrier
As a matter of operational doctrine it is preferred to turn carriers into the wind and make way to launch.
1d
comment What does the Pauli Exclusion Principle say about a superposition of spin states?
@PhotonicBoom To be in a superposition is to not be in either of the eigenstates. The probabilities implied only materialize when you measure the z-axis component of the spin. In the mean time it is not in either state along the z-axis. The statement Robin is objecting to is not correct on it's own, and the full answer requires you to anti-symmetrize the wave function to show the occupation limit does not depend on the spin axis you chose.
1d
comment Problem in the Ladder paradox in relativity?
Related (duplicate?): physics.stackexchange.com/questions/95327/pole-and-barn-paradox
1d
answered Is the molecule of hot water heavier than that of cold water?
2d
comment Who was the R. Dolen behind Dolen-Horn-Schmid duality?
This question appears to be off-topic because it is about a person rather than physics.
2d
comment Who was the R. Dolen behind Dolen-Horn-Schmid duality?
HepNames record that appears to be the right guy: inspirehep.net/author/profile/R.Dolen.2 He seems to have exactly 2 papers to his name (in the late 1960s), which suggests a grad student who went on to do things other than physics.
2d
comment What happens to an Electron when its charge is transferred elsewhere
The charge is an intrinsic part of the electron, and they can not "lose" their charge. You seem to have some very fundamental misunderstanding, but from the above text I can't guess what it might be.
Apr
20
comment Faraday's law and “infinite induction”
You are this close to discovering electromagnetic radiation...
Apr
20
comment Birds sitting on electric wires: potential difference between their feet
Note that in AC lines (which includes some but not all "high tension" lines) the potential difference between two points that are "nearish" can be dominated by the oscillation of the signal rather than the ohmic attenuation. With 50 or 60 Hz signals and standard issue birds this is not an issue, but the bare statement was bothering me.
Apr
19
comment What Did Nobelaureate Smoot Mean by “Modern Efforts to Find Violations of Special Relativity”
None that I have heard of, but that doesn't mean much ... there's lots of stuff going on that I don't hear about.
Apr
19
revised What Did Nobelaureate Smoot Mean by “Modern Efforts to Find Violations of Special Relativity”
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