CHINESE JOURNAL OF PHYSICS VOL. 38, NO. 3-I JUNE 2000
The explicit solution for the time evolution of the Nth rank spatial moment
(rj is the jth cartesian component of the position vector) of some field
has been obtained.
can be any spatially bounded massive field satisfying a relativistic first order linear (``Dirac-like'') differential equation, such as the Dirac bi-spinor. The solution for the Nth moment is a ``polynomial'' in time of degree N, whose coefficients are oscillatory functions with only the frequency
being present. The spin of the field
does not affect the form of the solution.
PACS. 03.65.Pm - Relativistic wave equations.
PACS. 03.50.-z- Classical field theory.
PACS. 03.65.-w- Quantum mechanics.