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I am a physics undergrad with interests in theoretical physics and mathematics.


Mar
6
comment Idea of Covering Group
@joshphysics: Sorry, I should probably use the word diffeomorphic rather than homeomorphic in my above comment.
Mar
6
comment Idea of Covering Group
@joshphysics: I am not being able to reconcile these facts. SU(2) is homeomorphic to the 3 sphere which is simple connected, and has the 0 to $2 \pi$ path can be shrunk to a point, so how does action by $SU(2)$ have periodicity $4 \pi$ in the context mentioned by Hunter above. Secondly, SO(3) is homeomorphic to $S^3 \backslash Z_2$ which is not simply connected and has the $0$ to $4 \pi$ path as the trivial loop, or identity map. How is this consistent with the fact that action by $SO(3)$(rotations in 3D space) have period $2 \pi$?
Mar
6
comment Church-Turing hypothesis as a fundamental law of physics
Deutsch's "Fabric of Reality" may be of interest to you. en.wikipedia.org/wiki/The_Fabric_of_Reality
Mar
6
comment 2nd - 3rd Year Physics Labs
Coming from a country, where undergrad labs are pathetic, I think this question could generate some excellent content. Looking forward for the answers. +1
Feb
20
awarded  Yearling
Feb
16
comment $(\frac{1}{2},\frac{1}{2})$ representation of $SU(2)\otimes SU(2)$
How does the dirac spinor transform in terms of $SO(3,1)$? I thought $SL(2, \mathbb{C})$ is the double cover of $SO^+(3,1)$ (the connected component of the lorentz group), and so the left and ring hand weyl spinor correspond to the fundamental rep of $sl(2,\mathbb{C})$. But according to your post, $(1/2,1/2)$ irrep corresponds to the 4-dim vector rep.
Feb
8
comment Lie derivative of a scalar and PDE
May more relevant and answered quicker on Math Stackexchange.
Feb
2
comment What does a $SU(2)$ doublet really mean?
Can another (perhaps better) geometric interpretation be given by using the fact that SU(2) represents $S^2$ as a manifold? How can you visualize the infinitesimal (one parameter?) transformations in this case. I don't like the idea of rotations in $\mathbb{C}^2$.
Jan
26
comment Gaussian Integral over Grassman variables
Just expand out $\psi^T M \psi$ in terms of the matrix elements, and use the formulae of grassman integration. The Determinant should come from the permutations of the matrix elements which can be written in terms of the levi-civita symbol.
Jan
23
revised How much time does it takes an electron to tunnel through a barrier?
added 44 characters in body
Jan
23
comment Is there a time delay during tunnelling?
related: physics.stackexchange.com/questions/82041/…
Jan
23
reviewed Approve suggested edit on Geometrical interpretation of the Dirac equation
Jan
23
answered How much time does it takes an electron to tunnel through a barrier?
Jan
23
answered Spin orbit coupling and fine structure of the Hydrogen atom
Jan
23
comment Change of QM Momentum operator under coordinate transformation
Ok! So what? $\frac{\partial}{\partial r^{\prime}}=\frac{\partial}{\partial r} \frac{\partial r}{\partial r^{\prime}}=\frac{1}{a} [1-r\frac{\partial a}{\partial r^{\prime}}]\frac{\partial}{\partial r}$
Jan
14
asked Roadmap to the Renormalization Group Approach
Jan
1
comment Supersymmetric generalisation of the bosonic $\sigma$ model in QM
Nice answer. Thank you.
Jan
1
accepted Supersymmetric generalisation of the bosonic $\sigma$ model in QM
Dec
25
asked Supersymmetric generalisation of the bosonic $\sigma$ model in QM
Dec
17
comment Prerequisites for QFT?
Haha, "I have a IQ of 160". LOL