34,505 reputation
347118
bio website inspirehep.net/…
location Duchy of Grand Fenwick
age 43
visits member for 3 years, 11 months
seen 21 mins 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.


Oct
15
comment How can we assume that reaching the speed of light slows down time?
We don't assume this, we measure it's effects. Every day.
Oct
15
revised Good Fiber Bundles reference for Physicists
Title are often very similar so physicists often refer to books by their author's (or s') name(s). Accordingly those names should generally be attached to please everyone.
Oct
15
comment Is it possible to have the principle of least action and multiple solutions?
Consider the path of a light ray from one focus of a thin lens to the other expressed in least action terms...
Oct
14
comment Can we observe proton decay?
"I know that the half life of a proton is $6.6\cdot10^{33}$ years (antimuon dacay)." Er ... I believe you know that the current lower experimental limit on the proton lifetime by that mode has that value.
Oct
14
comment Could we imagine spin as rotating probability densities (orbitals) in a kind of expanded orbital model?
The reason spin is not orbital motion is the $\mathbf{r} \times \mathbf{p}$ angular momentum gets the wrong quantization to agree with spin. Any kind of "rotating" is going to have that problem. Spin is angular momentum that has nothing to do with $\mathbf{r} \times \mathbf{p}$. That's really all there is to it.
Oct
13
revised what is the clear cut difference between isotropic and anisotropic spin exchanges
deleted 1 character in body; edited title
Oct
13
awarded  newtonian-gravity
Oct
12
revised Help with the inverse of a matrix
fix typesetting of the determinate operator
Oct
12
comment What is the Planck quantity of an expression?
You seem to be being asked (explicitly none-the-less) to raise things dimensional powers. That's nonsensical from the get-go.
Oct
12
comment Is it possible to prove conventional current is always equivalent to actual current?
Note that the Hall Effect unambiguously differentiates between the two cases, so it is not true that “whatever we can say about a current of positive charge particles flowing one way, we can say about electrons flowing to opposite way", but for the usual questions of circuit analysis it doesn't make any difference.
Oct
11
comment Does angular momentum slow as a spinning object moves faster?
See physics.stackexchange.com/questions/133376/… and physics.stackexchange.com/questions/34067/… and any number of other places where we have gone over the "relativistic mass" territory already.
Oct
11
comment Does angular momentum slow as a spinning object moves faster?
Despite its continued popularity in pop-sci and very-introductory treatments, a large fraction of physicists do not use "relativistic mass" anymore. Not because you can't do correct physics with that interpretation, but because it is not necessary and engenders more confusion (of the kind implicit in the question) than useful understanding. The short answer to your question is "no" and any belief that it might be yes comes from mixing a relativistic understanding of total energy (or mass if you insist) with a classical understanding of angular momentum (which is a no-no).
Oct
11
comment Gay-Lussac's Experiment with an Unmixed Gas
Please do not repost questions.
Oct
11
comment Do transmitters create magnetic fields and radiation?
@user3251930 It might help to know that the full glory of Maxwell's equations can be a pain except in fairly simple configurations, so people have sussed out some useful approximation regimes. The "far field" and "near field" in particular take on relatively simple expressions, and it is those (locally dominate) components of the complete solution to which CuriousOne refers. It's all "radiation" at some level, however.
Oct
10
comment Relation between torque and moment of inertia
A system of particles is not necessarily a rigid body, but a rigid body is a system of particles.
Oct
10
comment Physics First: Where is Science Education Today?
@Floris I don't think you understand what is being advocated by Dr. Lederman. No one is suggesting offering scary equations to 8th graders. A surprising amount of useful understading in physics can be gained with no more math then "When X gets bigger Y gets smaller" supported by the right demos and exploratory labs. Kids "get" momentum from day one in a way that they don't get force and acceleration, so they get collision experiments. They get the expansion of gasses when they are heated, so they get ideal gas behaviors in a up-versus-down level. Lederman's suggestion is play first.
Oct
9
comment Physics First: Where is Science Education Today?
@ChrisWhite Leon offers example curricula for entire years of education, and you don't need algebra much less calculus to teach a useful introduction to physics (I'm doing that in our "Intro. to Physical Science" class for poets and art majors right now). They aren't going to pass the AP exam with it of course but the assumption is that they will take a more mathematical calculus once they get to college rather than hoping to place out. The goal is to unify, motivate and illuminate high school science much better than is done now. All that said, I've never been anywhere that has tried it.
Oct
9
comment Physics First: Where is Science Education Today?
Leon never advocated for a discipline specific format for primary schools, only for secondary (which means starting in 6th or 7th grade in most places in the US) by which time they are already getting discipline specific instructions (again, in the US).
Oct
9
comment Is it possible for larger antimatter atoms to decay to matter and visa versa?
But neither case violates the conservation of baryon or lepton numbers which means the total amount of "matterness" is the same at the end of each process as at the beginning.
Oct
9
comment In a CMCS 2-body system, why does the speed of the particles after collision stay the same?
Just try conserving kinetic energy (because the collision is elastic) and momentum (always!) at the same time. There is only one solution. By trying it I mean write down the equations. It's a system of two equations in two unknowns, so it is solvable.