version 1.0.0

Bargmann-Michel-Telegi equation for the spin precession

equations

The treatment of the BMT equation for spin precession has been programmed. Let be the polarization defined by a normed vector with 3 components P (each component taking a value between -1 and +1) The BMT precession equation is the following :

The gyromagnetic anomaly a is normally equal to α/2π +O(α2), α being the fine structure constant. With a strong field a is a function of the field strenght, through the parameter :

This interpolation for the gyromagnetic anomaly has been programmed with the aid of polynomial approximations.

keywords

The BMT precessionis switched on by the keyword bmt_precession=1 in the $PARAMETERS:: field.

modification of the file formats

To each particle has bben associated the normalized polarization 3-vector. This polarization is added to the file beam1(2).dat