Find answers to your questions about Physics or help others by answering their Physics questions.
In quantum statistical mechanics we often define a density matrix as $rho = sum_{i} p_{i} | Psi_{i} rangle langle Psi_{i} | $. Its time volution is determined by the...
Asked on 06/01/2021
1 answerWell, the definition of electromagnetic waves in a couple of textbooks is stated to be, 'A wave produced or resulting from the accelerated motion of a charged particle'. My question...
Asked on 06/01/2021 by Boingboingboing
1 answerFor example if I place a block (at $t=0$) on a disc which is rotating about its axis, should I consider the velocity of block as zero at ...
Asked on 06/01/2021 by Latha Prem
1 answerConsider a thin spherical conducting shell of radius $R$, which carries a total charge $Q$ on its surface.Two point charges $Q$ and $2Q$ are at...
Asked on 06/01/2021 by ash07
1 answerImagine a four-velocity $U^mu(x)$ defined all over spacetime. Define the number-flux four-vector as$$N^mu = nU^mu$$where $n$ is the number density of a collection of particles...
Asked on 06/01/2021
1 answerIn Matthew Schwartz Quantum Field Theory and Standard Model the author presents the Parke-Taylor formula$tilde{M}(1^+2^+...j^-...k^-...n^+) = frac{langle j k rangle^4}{langle 1 2 rangle langle 2 3 rangle ...
Asked on 06/01/2021
0 answerThe Christoffel symbols are symmetric with respect to the lower indices. This property is based on the geometric condition of path independence of the incremental vector. (Geometry of the flat...
Asked on 06/01/2021 by NSRG
1 answerIf we have two cubic cavities both with perfectly reflecting walls, one much large than the other, both with a blackbody in them, then when they are both in thermal...
Asked on 06/01/2021
0 answerThe well known and frequently used Israel Junction conditions are the equivalent of Einstein's field equation on a membrane in the brane-world picture. All the sources have...
Asked on 06/01/2021
2 answerIn Weinberg QFT Vol. 1 Eq. 6.1.14, he defines the propagator for a fermion to be$$ theta(x-y){psi^+(x),psi^+{}^dagger(y)} - theta(x-y){psi^-{}^dagger(x),psi^-(y)}$$where $psi^+$ annihilates particles, and $psi^-$ creates...
Asked on 06/01/2021 by Eric David Kramer
2 answerGet help from others!
Recent Questions
Recent Answers
© 2024 TransWikia.com. All rights reserved. Sites we Love: PCI Database, UKBizDB, Menu Kuliner, Sharing RPP