# Can you give some examples of vector precession equation dS/dz=ΩxS?

1. Nov 10, 2012

### andonrangelov

Hi All,
I know that vector precession equations such as mdV/dt=qBxV (Newton's Second Law written for the magnetic part of the Lorentz force) exist.
In the last equation magnetic field B=(B1,B2,B3) acts as an effective torque and the speed V=(V1,V2,V3) is the “pseudo-spin vector”.
These equations can be written also as:

mdV1/dt=-qB3V2+qB2V3
mdV2/dt=qB3V1-qB1V3
mdV3/dt=-qB2V1+qB1V2

I know three applications of these equations:
1) Optical Bloch equations written for two-level atom;
2) Stokes equation of polarization optics;
3) Gyroscope precession

Can someone give other physical applications of the vector precession equation
(dS/dz=ΩxS)?