Zero track elimination function. Inspects the first few steps in the system trajectory and drops the states that did not get populated to a user-specified tolerance. The default tolerance may be altered by set- ting sys.tols.zte_tol variable before calling create(). Syntax:
L - the Liouvillian to be used for time propagation
rho - the initial state to be used for time propagation
nstates - if this parameter is specified, only nstates most populated states are kept, irrespective of the to- lerance parameter
projector - projector matrix into the reduced space, to be used as follows: L_reduced=P'*L*P, rho_reduced=P'*rho;
Further information is available in IK's JMR paper on the subject:
It is a good idea to disable ZTE in systems with nearly equivalent spins.