37,738 reputation
648125
bio website arXiv.org
location Europe
age 48
visits member for 3 years, 7 months
seen 5 hours ago

I'm a theoretical physicist.


4h
comment What is $g$ when traveling quickly around a planet?
Hi Friend of Kim. If you haven't already done so, please take a minute to read the definition of when to use the homework tag, and the Phys.SE policy for homework-like problems.
6h
comment These two operators commute…but their eigenvectors aren't all the same. Why?
$\uparrow$ Agree.
7h
comment Do we exist in multiple dimensions?
Related: physics.stackexchange.com/q/10527/2451 , physics.stackexchange.com/q/83492/2451 and links therein.
7h
comment These two operators commute…but their eigenvectors aren't all the same. Why?
It is interesting to note that the theorem talks about diagonalizable operators (rather than selfadjoint operators, although admittedly the latter is what is relevant for QM). Being diagonalizable is a generic property. Being selfadjoint is a special property.
8h
comment Topology of phase space
Comment to the question (v3): See V.I. Arnold, Mathematical methods of Classical Mechanics, $\S49$.
9h
comment Non-integrability of the 2D double pendulum
Comment to the question (v4): The total external torque $\tau_z=\frac{dL_z}{dt}$ (produced by gravity) around the suspension point, is rarely zero. Hence $L_z$ is not an integral of motion.
12h
comment Index notation with Navier-Stokes equations
Hi @miro2: ...and a reference?
16h
comment In QED, why is the $e^- + e^+\leftrightarrow\gamma$ process forbidden on-shell?
Related: physics.stackexchange.com/q/13513/2451 , physics.stackexchange.com/q/22916/2451 , physics.stackexchange.com/q/12488/2451
22h
comment Dielectric slab counter-intuitive formula?
Comment to the question (v6): Consider to add a reference for the formula to make the question more accessible.
1d
comment The classical hydrogen atom
Hi @BMS: I took out the word QM in the question formulation because it seems OP would like to try to understand the hydrogen atom without using QM.
1d
comment Non-integrability of the 2D double pendulum
If you like this question you may also enjoy reading this Phys.SE post.
1d
comment Group representations as vectors and isomorphism between weights and matrix generators
Related: physics.stackexchange.com/q/52417/2451 and physics.stackexchange.com/q/41424/2451.
2d
comment How can light have the same speed for all observers?
Possible duplicates: physics.stackexchange.com/q/2230/2451 and links therein.
2d
comment Can light produce weak gravitational waves?
Related: physics.stackexchange.com/q/14064/2451 and links therein.
2d
comment Photons and Black holes
Related: physics.stackexchange.com/q/14064/2451 and links therein.
2d
comment Why charge is an extensive property
Hi P.A24. Please don't repost a closed question in a new entry. Instead, you are supposed to edit the original question within the original entry.
2d
comment Why charge is an extensive property
Possible duplicate by OP: physics.stackexchange.com/q/141284/2451
2d
comment Grassmann number representation for fermions
Comment to the question (v2): The equation $c\left|0\right>+\left|0\right>c = 0$ should be $c\left|0\right>-\left|0\right>c = 0$. Similarly for the equation with $\overline{c}$.
2d
comment What does it mean by $t=-1$?
Hi alethiologist. Welcome to Phys.SE. If you haven't already done so, please take a minute to read the definition of when to use the homework tag, and the Phys.SE policy for homework-like problems.
2d
comment How to show that the force and velocity are perpendicular and that both have constant magnitude?
Hi alethiologist. Welcome to Phys.SE. If you haven't already done so, please take a minute to read the definition of when to use the homework tag, and the Phys.SE policy for homework-like problems.