29,873 reputation
33994
bio website inspirehep.net/…
location Duchy of Grand Fenwick
age 43
visits member for 3 years, 5 months
seen 1 min 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.


1m
comment How do moving charges produce magnetic fields?
@SachinShekhar "For magnetic field production, you need acceleration, not uniform speed..." is incorrect. Observe the appearance of the electric current (i.e. and and all charges in motion) in Maxwell's Equations. Acceleration gives you radiation.
1h
comment Is it really “time” that is dilating?
@aepryus Perhaps I should mention that this was not meant to encourage you. The road you are following is--in my estimation--not even wrong. The things that relativity tells us about the way the universe works are very well checked and very fundamental. The intuitive picture of space and time that you (and I and everybody else) have in your head is simply incorrect. Space-time really does mix as you change velocity.
2h
comment Is it really “time” that is dilating?
A pendulum clock is a timing mechanism that relies primarily on gravity. You can even use a weight and chain drive to run the thing.
4h
comment Is it really “time” that is dilating?
The plain fact of the matter is that radioactive decay clocks confirm SR's prediction to very (very!) high precision And so do atomic oscillation clocks. Moreover, the prediction of GR (recall that subsumes SR) concerning the behavior of time (and gravitational lensing and frame dragging) in a gravitational field have also been tested. (When LIGO finally reports success we'll have the last big piece of the puzzle.)
11h
revised How we can manipulate the momentum of a particle?
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11h
comment The invariant interval
Yes, it makes the interval invariant. The interval is one example of a "Lorentz scalar" and the whole class is distinguished by being invariant under Lorentz transformations. Showing that this is so is often an exercise early in a unit on special relativity.
11h
comment What might be the reason that more dense materials are better at shielding?
Related (approaches a duplicate in some ways): physics.stackexchange.com/questions/11506/…
11h
comment Why use lasers for intense, localized heat instead of some other light source?
You have to look at each, individual use and ask yourself "Which properties are needed here, which are convenient and which superfluous?" and then compare to the things you suggest are alternatives (this is, after all, what the engineers who made those choices did). And recall that "laser" covers a lot of ground ...
12h
revised Looking for an Time Series Analysis Text
edited tags
12h
comment Weird consequence of Gauss's law
The usual introductory examples make use a carefully chosen symmetries to let you relate the net flux (which Gauss' law talks about) to the field itself (which it does not). This is one origin of student confusion on the matter.
12h
revised Cooling power for cloud chamber
edited tags
13h
comment Basic magnet through a copper coil experiment - What if poles were rotated 90 degress
Be aware that actual bar magnets--such as the ones found in intro physics laboratories--typically do not have highly symmetric field shapes. The experimental result would likely be a very weak and "wibbly-wobbly" signal.
22h
comment Cooling power for cloud chamber
If you know someone who runs a LN2 cooled chamber of similar design their mass loss rate might provide a first estimate. Have Peltier coolers gotten a lot more efficient while I've been distracted?
1d
revised How we can manipulate the momentum of a particle?
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1d
comment Need help solving a task - laws of conservation (leptons, baryons, charge)
Another note. In the MeV and low GeV energy range, neutrino--nucleon cross-sections are rising approximately linearly with energy, not falling. This is a consequence of the cross-section being dominated by the weak boson masses, which makes it unlike, say t-channel electron-nucleon scattering where cross-sections in this energy range are falling as $Q^2$ increases.
1d
comment Need help solving a task - laws of conservation (leptons, baryons, charge)
The answer that you have accepted below is incorrect. Look carefully at lepton number conservation in the proposed reactions.
1d
comment Need help solving a task - laws of conservation (leptons, baryons, charge)
I hate to tell you this, but this answer is completely wrong. We observe this reaction which we describe as "quasi-elastic neutrino scattering with pion production". It does require that the neutrino is energetic. The correct answer turns on identifying the correct lepton numbers of the neutrinos and charged leptons.
1d
comment How we can manipulate the momentum of a particle?
The answer I have given below may seem trivial, but if you are somehow thinking that momentum is an intrinsic property of the object than you have gotten hold of a misunderstanding.
1d
answered How we can manipulate the momentum of a particle?
2d
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.