1,429 reputation
1613
bio website code.google.com/p/notebk
location Los Angeles, CA
age
visits member for 2 years, 7 months
seen 2 hours ago

A mathematician, a programmer, etc. etc.

My interests are limited to classical general relativity, quantum gravity, mathematical aspects of quantum field theory, and related fields.


Dec
4
comment Derivation of Kerr metric, is there any reference?
@KyleKanos, yep, it's paywalled.
Nov
16
comment What kind of math is used in QFT?
"Feynman Path Integrals." That's not a field of math, per se, unless you're talking about measure theory on path spaces...I would also think "Functional Analysis" or "Operator Algebras" would prove useful...
Nov
15
comment Is it possible to have fermions in Schwarzschild spacetime?
And, lo!, you can have fermionic quantum field theory on curved spacetime, set in a black hole setting; see Syed Alwi B. Ahmad's doctoral thesis Fermion Quantum Field Theory In Black-hole Spacetimes. It seems that you may have to consider spacetime as $\mathbb{R}^{4}-(\mathbb{R}\times D)$ where you just "cut out" the event horizon (and its interior), and construct your spinor field on the rest of spacetime...
Nov
15
comment Is it possible to have fermions in Schwarzschild spacetime?
A quick google search gave this interesting preprint "Twisted spinors on black holes" arXiv:gr-qc/9905038, and "Spinor fields near black hole singularities" Class. Quant. Grav. 12 no 3 (1995) 841
Nov
12
revised Are terms with spinors analogous to $ ( \partial_\mu \Phi )(\partial^\mu \Phi)$ forbidden in the Lagrangian?
Fixed mass-dimension errors -_-'
Nov
12
comment Are terms with spinors analogous to $ ( \partial_\mu \Phi )(\partial^\mu \Phi)$ forbidden in the Lagrangian?
@Siva Good catch!
Nov
12
comment Do physicists use agent based models?
Most "agent-based" modeling in physics turns out to be fairly simple; I vaguely recall seeing how one could turn any PDE into a cellular automata, which for physics (barring something horrible like rotating binary Pulsars in GR or something) is fairly simple...it was a popular topic in the late '80s IIRC, the died out for some reason...
Nov
12
answered Are terms with spinors analogous to $ ( \partial_\mu \Phi )(\partial^\mu \Phi)$ forbidden in the Lagrangian?
Oct
30
comment is the renormalization unique?
This is a fairly cryptic post...
Oct
30
comment Renormalization, integrating out high momenta Wilson way
I think your first line should be $\int\phi^2 d^4x = \int(\int\phi_{k}\phi^{*}_{k'}e^{i(k-k')x}d^{4}k\, d^{4}k')d^{4}x$ otherwise...you get a different result. (But the rest of your reasoning appears to be fine, modulo technical details concerning the Fourier transform and so on which are irrelevant to the question anyways)
Oct
30
comment Renormalization, integrating out high momenta Wilson way
Question to ponder: When we Fourier transform $\phi(x)\to\widetilde{\phi}(k)$, what does $\widetilde{\phi}(k)$ look like in terms of the creation and annihilation operators $a_{k}$ and $a^{\dagger}_{k}$?
Oct
30
comment Bosonic Schrödinger field
well, perhaps think about this: what do we expect from $[b_{i}(t), b^{\dagger}_{i}(t)]=??$ What happens if you let $[b_{i}(t), b^{\dagger}_{j}(t)]=f_{ij}(t)$, what properties of $f_{ij}(t)$ should hold (i.e., is it symmetric? Hermitian? Self-adjoint? What's its diagonal?)? What happens when you plug this back in, and use these properties?
Oct
30
revised Bosonic Schrödinger field
Mildly improved the TeX formatting
Oct
30
comment Bosonic Schrödinger field
This is one of those questions where I'd like to answer, but the best solution is for you to struggle with this for a while...
Oct
30
suggested approved edit on Bosonic Schrödinger field
Oct
14
comment What is the difference between the compact U(1) group and non-compact U(1) group?
@WetSavannaAnimalakaRodVance Well, since $U(1)$ is the topological compactification of $\mathbb{R}$, topologically it makes sense to think of $(\mathbb{R}, +)$ as the "non-compact" version of $U(1)$.
Oct
10
revised Correspondence between one-parameter subgroups of $G$ and $T_eG$
Improved formatting
Oct
10
suggested approved edit on Correspondence between one-parameter subgroups of $G$ and $T_eG$
Oct
3
comment QFT Hilbert spaces over other rings than the complex numbers $\mathbb{C}$
An article on a related topic, which may interest the OP, Twisted de Rham cohomology, homological definition of the integral and "Physics over a ring"...
Oct
1
answered Classical Hamiltonian involving product of factors whose quantum analogues don't commute