22,969 reputation
152123
bio website lightandmatter.com
location Fullerton, California
age
visits member for 3 years, 2 months
seen 8 hours ago

I teach physics at Fullerton College, a community college in Southern California. I have an undergrad degree in math and physics from Berkeley and a PhD in physics from Yale. Back when I was doing research, my field was experimental low-energy nuclear physics.


Oct
13
comment Can we quantize Aristotelian physics?
@KeshavSrinivasan: The real point is that the motion is dissipative, in the sense of Liouville's theorem. This is incompatible with standard QM.
Oct
13
answered Signs in proof of gravitation potential energy (GPE)
Oct
13
comment Can we quantize Aristotelian physics?
@user23660: From the paper: "This would render theory of dissipative and non-Hamiltonian systems a fundamental generalization of quantum mechanics." I think this supports my point.
Oct
13
comment Arguments for and against Many Worlds?
@JustinL.: MWI is philosophy, but it might be better to say that all interpretations of quantum mechanics are philosophy.
Oct
13
comment Can we quantize Aristotelian physics?
@KeshavSrinivasan: What's going on here is basically Liouville's theorem. if a particle enters a region where there's no force acting on it, then it's quantum state will have no information about its prior acceleration. This is really classical, not quantum, and your statement is not true. Given the present value of $x$ and $\dot{x}$ for every particle, you can extrapolate the motion back into the past to find $x(t)$ for every particle. Then by differentiating twice you get every particle's acceleration at all times in the past.
Oct
13
comment Can we quantize Aristotelian physics?
@KeshavSrinivasan: Try these links: en.wikipedia.org/wiki/Unitarity_%28physics%29 motls.blogspot.com/2008/06/black-hole-information-puzzle.html
Oct
12
answered Can we quantize Aristotelian physics?
Oct
12
revised Equivalences and derivations in Newtonian/Classical Mechanics
added 285 characters in body
Oct
12
comment Equivalences and derivations in Newtonian/Classical Mechanics
@RS: Yes, Newton's laws can all be proved from conservation of energy and momentum (or from conservation of energy and Galilean relativity).
Oct
12
comment Equivalences and derivations in Newtonian/Classical Mechanics
The proof on proofwiki says, "The final part of the third law is that these conjugate forces act on through the line that connects the two bodies in question." This is wrong. For an English translation of what Newton's original formulation of the third law says, see archive.org/stream/newtonspmathema00newtrich#page/n87/mode/2up , p. 83.
Oct
12
answered Are Stephen Crothers' claims legitimate?
Oct
12
revised Equivalences and derivations in Newtonian/Classical Mechanics
added 68 characters in body
Oct
12
comment Equivalences and derivations in Newtonian/Classical Mechanics
@RS: You need both the 2nd law and the 3rd law to prove conservation of momentum. Can you give a link to the proof you're referring to re angular momentum? It's either wrong or it invokes additional assumptions.
Oct
12
comment Riemann tensor notation and Christoffel symbol notation
The standard notation for that would be the following. Rather than writing $T_{ab}-(a\leftrightarrow b)$, you would write $T_{[ab]}$.
Oct
12
answered Equivalences and derivations in Newtonian/Classical Mechanics
Oct
12
comment Equivalences and derivations in Newtonian/Classical Mechanics
As originally formulated by Newton, the first law was a special case of the second. Later, influenced by Mach, textbook authors started presenting it as a statement about the existence of inertial frames. See physics.stackexchange.com/questions/13557/… .
Oct
12
comment Are Stephen Crothers' claims legitimate?
I'm downvoting for the reasons given here: meta.physics.stackexchange.com/q/4918 . If the OP wants to replace or supplement the video link with a link to Crothers' papers on vixra, I'll be happy to remove my downvote.
Oct
12
comment How faster is the effect of force exerted by gravity?
Now let us say, hypothetically if the sun were to suddenly extinguish (or disappear), This would be inconsistent with general relativity, which requires local conservation of mass-energy. You can move the sun away very quickly, but you can't just make it disappear.
Oct
12
comment How faster is the effect of force exerted by gravity?
The answer to this question is not resolved yet. Not true. The issue is well understood and has been tested empirically, as discussed in the answers to the question that this one duplicates.
Oct
11
reviewed Approve suggested edit on How to find the compression of a spring attached to an object