Discussion of 385(5) Part Two

Thanks again!

To: EMyrone@aol.com
Sent: 13/08/2017 13:41:53 GMT Daylight Time
Subj: Correction Re: Discussion of 385(5)

correction: the signs of E and A are correct.


Am 13.08.2017 um 14:39 schrieb Horst Eckardt:

The expressions for E and A, eqs. (26) and (27) of note 385(2), are nearly correctly. A needs a negative sign and the factor for the Y components is YZ instead of XY.
As I mentioned, the scalar spin connection -c/r is not compatible with the equations, I also computed A for the spin connection -c/r*cos(theta) (see eq. o14 of the prtocol, compared to o12). I will do some graphics next to show the difference.


Am 11.08.2017 um 15:16 schrieb EMyrone:

Many thanks, take it easy until the cold gets better. Use the potential of Eq. (11), which translates into eq. (27) in Cartesian coordinates, and check that I have correctly converted from spherical polar to cartesian. Then compute and plot the spin connections. The rigorously general potential is Eq. (9), which is a bit more difficult. I agree about labelling the potentials. We are moving into completely new territory once again

Sent: 11/08/2017 11:19:33 GMT Daylight Time
Subj: Re: Discussion of 385(5)

Currently I have catched a cold and am a bit limited in thinking 🙂
I will study your answer later in detail. What exactly should I work out for eqs.(10) of note 385(2)? What should I put in for bold A? Or should bold A result from theses equations, together with bold omega?
The fact that we use the same symbols in different context may be a source of problems. I suggest to add an index E or B for all potentials A as well as spin connections omega_0, bold omega. I will try to make a table where the relevant equations with the fields A_E, A_B etc. are listed.


Am 11.08.2017 um 10:23 schrieb EMyrone:

Thanks again. The antisymmetry conditions (8) to (10) of Note 385(1) originate in the magnetic part of the electromagnetic field tensor. Eqs. (11) to (13) come from Eq. (7), defining the absence of a magnetic flux density. The antisymmetry laws are written out in tensor notation in Eq. (22) of Note 379(5). The electric antisymmetry law is Eq. (23), and the vector potential is “electric” in the sense that it defines an electric field strength as in Eq. (22). If there is an electric field strength E present and no magnetic flux density B, then F sub 0i, i = i, 2, 3 are non zero, but F sub ij j, i , j = 1,2,3 are all zero. The former are the electric elements of the field tensor and the latter are the magnetic elements. The vector potential is called “electric” if there is no magnetic flux density present. It is called “magnetic”, if there is no electric field strength present. For Note 385(5) I had in mind simply working out Eqs. (17) to get the spin connections, and to check my hand derivation of Eq. (18) by computer algebra. I had in mind using firstly the constant omega sub 0 of Eq. (4), and secondly the omega sub 0 of Eq. (20). Eq. (18) of Note 385(5) comes from Eqs. (8) to (13) of Note 385(1). For the electric dipole field and an assumed B = 0 and partial A / partial t = 0, the vector potential is given the name “electric vector potential” because there is no magnetic flux density present. There is no incompatibilty between Eqs. (8) to (10) of Note 385(1), and Eqs. (11) to (13) of Note 385(1) because they use elements of the same overall four potential A sub mu, defined by

F sub mu nu = D sub mu A sub nu – D sub nu A sub mu

where F is the field tensor and D the covariant derivative. The antisymmetry laws originate in:

F sub mu nu = – F sub nu mu

which implies

D sub mu A sub nu = – D sub nu A sub mu

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