Spinlock.m

Analytical approximation to the spin-locking process that removes all spin-spin correlations and all magnetisation components except those along the indicated direction.

Syntax

    rho=spinlock(spin_system,Lx,Ly,rho,direction)

Parameters

     Lx         - X magnetization operator on the spins that
                  should be locked

     Ly         - Y magnetization operator on the spins that
                  should be locked

     rho        - state vector or a bookshelf stack thereof

     direction  - direction in which the spins should be lo-
                  cked, 'X' or 'Y'.

Returns

     rho        - state vector or a bookshelf stack thereof

Examples

The following code fragment is used for spin locking in roesy.m:

    % Pulse operators
    Lp=operator(spin_system,'L+',parameters.spins{1});
    Lx=(Lp+Lp')/2; Ly=(Lp-Lp')/2i;

    % Analytical spin lock
    rho_stack_cos=spinlock(spin_system,Lx,Ly,rho_stack,'Y');
    rho_stack_sin=spinlock(spin_system,Lx,Ly,rho_stack,'X');

Notes

This is an approximation to what happens during a real spin locking process. If you need a very accurate simulation, you would need to model the spin locking explicity by adding RF terms to the system Hamiltonian.

See also

coherence.m, correlation.m, homospoil.m

Version 1.10, authors: Ilya Kuprov