I Sign of the spatial part of the J.J interaction

gernos
Messages
1
Reaction score
0
TL;DR Summary
Is the ##A_\mu J^\mu## interaction energy between two separated identical current densities positive (repulsive) or negative (attractive) ?
I think it is negative because of the ##g_{\mu \nu}## metric tensor, but I am not sure.
 
Last edited by a moderator:
Thread 'Gauss' law seems to imply instantaneous electric field propagation'

Thread 'Gauss' law seems to imply instantaneous electric field propagation'

Imagine a charged sphere at the origin connected through an open switch to a vertical grounded wire. We wish to find an expression for the horizontal component of the electric field at a distance ##\mathbf{r}## from the sphere as it discharges. By using the Lorenz gauge condition: $$\nabla \cdot \mathbf{A} + \frac{1}{c^2}\frac{\partial \phi}{\partial t}=0\tag{1}$$ we find the following retarded solutions to the Maxwell equations If we assume that...
View full post »
Thread 'Griffith, Electrodynamics, 4th Edition, Example 4.8. (First part)'

Thread 'Griffith, Electrodynamics, 4th Edition, Example 4.8. (First part)'

I am reading the Griffith, Electrodynamics book, 4th edition, Example 4.8 and stuck at some statements. It's little bit confused. > Example 4.8. Suppose the entire region below the plane ##z=0## in Fig. 4.28 is filled with uniform linear dielectric material of susceptibility ##\chi_e##. Calculate the force on a point charge ##q## situated a distance ##d## above the origin. Solution : The surface bound charge on the ##xy## plane is of opposite sign to ##q##, so the force will be...
View full post »

Thread 'Simple thought experiment with Stefan-Boltzmann law: energy'

Dear all, in an encounter of an infamous claim by Gerlich and Tscheuschner that the Greenhouse effect is inconsistent with the 2nd law of thermodynamics I came to a simple thought experiment which I wanted to share with you to check my understanding and brush up my knowledge. The thought experiment I tried to calculate through is as follows. I have a sphere (1) with radius ##r##, acting like a black body at a temperature of exactly ##T_1 = 500 K##. With Stefan-Boltzmann you can calculate...
View full post »

Similar threads

B Problems I Have With Electrostatics and Pith Ball Experiments
Replies
10
Views
4K
A Dirac on localization of energy in the gravitational field
Replies
16
Views
2K
I Deriving Geodesic Equation from Lagrangian
Replies
7
Views
3K
A Variation of the kinetic term in scalar field theory
Replies
1
Views
1K
A Bivector mediation of standard field equations to form coupled system
Replies
17
Views
1K
A Can gravitational energy be localized in the case of plane waves?
Replies
8
Views
2K
I Weak Interaction Hamiltonian V-A Structure Derivation
Replies
0
Views
600
A The wave vector ##k_\mu## in curved spacetime
Replies
4
Views
1K
I Linearized Gravity & Metric Perturbation when Indices Raised
Replies
17
Views
2K
I How do Tensors "work" in relation to linear algebraic objects?
Replies
7
Views
283

Hot Threads

Recent Insights

Back
Top