It is known that electromagnetic (EM) fields action on particles is limited to the Lorentz force action. In terms of spinors and currents, the EM field:

(i) rotates the Dirac current around the direction of the field $B$ to the angle proportional to the magnitude of $B$, and

(ii) "accelerates" the Dirac current in the direction of $E$ to the extent proportional to the magnitude of $E$.

Action of Lorentz force exhausts all possible rotations and boosts.

In fact, nothing else could "happen" to the Dirac current (which is a Minkowski space 4-vector) except (a) rotation and boost described above, and (b) change in magnitude of the Dirac current vector prohibited by conservation of charge and/or mass.

Unless the action of weak and strong forces is always limited to change of mass/charge of the particle, is it possible to consider the effect of these forces on particles as a kind of "special" electromagnetic action?

  • $\begingroup$ This is not true--- you are thinking of the classical effects. There are also spin interactions in the Dirac equation. Your question would be better (and answered!) if you asked "what is the classical force from the SU(2) and SU(3) gauge field on a heavy source" This is physical, and similar to the Lorentz force. $\endgroup$
    – Ron Maimon
    Apr 15, 2012 at 7:32

1 Answer 1



The weak force acts on uncharged particles, has the wrong range behaviors, violates symmetries that the electromagnetic force is known to respect, and is much too, well, weak.

The strong force has the wrong range behavior and is much to, well, strong.

  • 1
    $\begingroup$ well, if we go into the su(2)xsu(3)xU(1) standard model we may is say that it is inspired by the gauge invariance of the electromagnetic U(1) extended to higher dimensional and different symmetries? $\endgroup$
    – anna v
    Mar 24, 2012 at 16:17

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