Jerry Schirmer

Austin, TX

Age: 35

I am a Ph.D. general relativist working as a software engineer. I like to still go and do physics as a hobby, and to keep up my skill and knowledge.

2d
comment Is it possible for a physical object to have a irrational length?
@JánLalinský: sure, but the actual result will be a sum by quadrature of several such measurments, which will still be an irrational number.
Feb
28
answered How does one experience single gravitons and/or Planck-force?
Feb
27
comment What is the meaning of Einstein's field equation in terms of source and its effects on curvature?
The source of the curvature would be the spherically symmetric central body. If we are outside of the body, then there is no matter source, but that doesn't mean that there is no matter anywhere.
Feb
24
answered Are black holes hot?
Feb
24
answered What is the difference between leptons and baryons?
Feb
24
answered Is there any paper analyzing the validity of Relativity in expanding space?
Feb
17
answered Object inheritance in Neo4j hibernate OGM
Feb
17
asked Object inheritance in Neo4j hibernate OGM
Feb
17
answered Any alternatives to Spring Data Graph, jo4neo, ogrm?
Feb
16
comment why the electromagnetic wave transmits momentum in the direction of the movement?
@lemon: EM waves carry momentum classically.
Feb
16
answered Why do we lose signal in elevators?
Feb
16
comment What is the relation between $\eta^{ab}x^2$ and $x^ax^b$?
A tensor like $x^{a}x^{b}\eta^{ab}$ is not a valid tensor. Do you mean $x_{a}x_{b}\eta^{ab}$?
Feb
16
comment What is the heat sink in an internal combustion engine?
The exhaust....
Feb
15
comment What does the net force do with this droplet in magnetic field?
I would be shocked if the solution to this problem didn't involve lagrangian analysis of the problem, and looking for some sort of configuration that minimzed the energy
Feb
13
comment The fainter the star, the further away it is?
This is the key historical problem in observational astronomy. It took a lot of effort and insight to figure out the answer, and whole books have been written on how to devise tricks in order to get independent measurements of either the distance to a star or its absolute luminosity.
Feb
13
comment Uniqueness or multiplicity of ADM masses for spacetime manifolds with more than one "end"?
@JulianMoore :Yes, that's pretty much the idea -- you can specify some boundary condition, and from that boundary condition evolve to get the whole initial timeslice, subject to the constraint. The work along this line was worked out by York and Choques-Bruhat. This link kind of follows the general idea: math.msu.edu/~gnagy/papers/talk-10-2010-h.pdf
Feb
12
comment QCD and QED with unlimited computational power - how precise are they going to be?
Also, lattice QCD is a program to non-perturtabatively calculate out QCD phenomenon, without resorting to this series.
Feb
11
comment Given that matter cannot escape a black hole, how did the big bang produce the universe we see today?
You don't need to invoke the breakdown of general relativity to show that the big bang wasn't a black hole. General relativity, alone, already predicts that the big bang singularity is distinct from black hole singularities.
Feb
8
comment It's established that universal energy is not constant. But is the net change positive or negative?
@Christoph: and you can do various extensions from the Schwarzschild-de Sitter universe to an expanding universe and get some sort of notion of energy that way, too. None of it really meaningfully answers the OP's question, though.
Feb
8
comment Uniqueness or multiplicity of ADM masses for spacetime manifolds with more than one "end"?
@JulianMoore: Here's my issue with this -- The Hamiltonian and Momentum constraints are a set of elliptic equations on the three-manifold. Therefore, a complete set of $\gamma_{ij}$, $K_{ij}$ and their derivatives on a 2-surface should yield the whole 3-manifold. This should preclude discontinuous things like gluing. But I don't see an obvious reason why, other than that.
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