256 reputation
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age 23
visits member for 3 years, 3 months
seen Sep 12 at 2:48

Jul
2
awarded  Curious
Mar
20
awarded  Popular Question
Sep
10
comment A question about Killing vector and Riemann curvature tensor
I've left the field of math and physics and am no longer able to decipher these symbols. Sorry about your first answer. But someone else who has the same problem may one day find you answer helpful.
May
15
awarded  Caucus
Dec
29
asked Is it possible to further simplify the product of three exponentials $e^A e^B e^C$ when $[A,C]=kB$ (k is a scalar)
Sep
14
awarded  Commentator
Sep
14
comment Complex analysis and powers of complex values
Shouldn't the second one be $\pm 1$? Since complex power to fraction is multivalued.
Sep
14
accepted Why is positivity of first entry sufficient for a matrix in $\mathrm{SO}(1,3)$ to be in $\mathrm{SO}^{+}(1,3)$?
Sep
14
awarded  Yearling
Sep
14
awarded  Editor
Sep
14
revised Why is positivity of first entry sufficient for a matrix in $\mathrm{SO}(1,3)$ to be in $\mathrm{SO}^{+}(1,3)$?
added 27 characters in body
Sep
14
asked Why is positivity of first entry sufficient for a matrix in $\mathrm{SO}(1,3)$ to be in $\mathrm{SO}^{+}(1,3)$?
Jun
20
comment What transforms under SU(2) as a matrix under SO(3)?
I stated clearly in my question: what is the equivalent transformation in SU(2) of the rotation of a linear operator (matrix) instead of vector in $\mathbb{R}^3$?
Jun
20
comment What transforms under SU(2) as a matrix under SO(3)?
You are just re-expressing what I already know, that $\left( \boldsymbol{r}'\cdot\boldsymbol{\sigma} \right) = \boldsymbol{h} \left( \boldsymbol{r}\cdot\boldsymbol{\sigma} \right) \boldsymbol{h}^{-1}$.
Jun
20
comment What transforms under SU(2) as a matrix under SO(3)?
@QiaochuYuan: I didn't learn the concept of "pullback". Can you elaborate?
Jun
20
asked What transforms under SU(2) as a matrix under SO(3)?
Jun
7
comment Inverse boson operator realization of $\mathfrak{so}(3)$
@QiaochuYuan: $J_{+}=a_{1}^{\dagger}a_{2},\ J_{-}=a_{1}a_{2}^{\dagger},\ J_{z}=\frac{1}{2}\left(N_{1}-N_{2}\right) $ where $a_1$ and $a_2$ are two commuting annihilation operator.
Jun
7
asked Inverse boson operator realization of $\mathfrak{so}(3)$
May
24
comment Sum of the reciprocal of sine squared
Where are the promised more details?
May
24
accepted Sum of the reciprocal of sine squared