partner_state.m

Partner state expansion; a given state of the specified spins is kroneckered with all combinations of the specified states of specfied partner spins.

Syntax

[A,descr]=partner_state(spin_system,set_spin,partners)

Arguments

set_spin    - a cell array of two-element cell arrays
                 with the first element giving the state
                 of the spin and the second element num-
                 ber on the isotope list, for example

                               Template:'L+',3

                 These spins will have their states set
                 immutably as specified.

   partners    - a cell array of partner state specifica-
                 tions of the form

                         { {states_a,spins_a},...
                           {states_b,spins_b},... }

                 where states_a,b are cell arrays of sta-
                 tes that the partner spins can have and
                 spins_a,b are lists of numbers of those
                 spins on the main isotope list, e.g.

                        { {{'E'  'Lz'},[1 5]},...
                          {{'L+' 'L-'},[2 7]},... }

                 These spins will have their state varied
                 combinatorially as specified.

Outputs

A - a cell array of spin states (matrices in Hilbert space,
       vectors in Liouville space) with the active spin in the
       specified state and the partner spins in all combinati-
       ons specified by the user. All spins not explicitly
       mentioned in the input will be in their 'E' states.

   descr - a cell array of product structure descriptors for
           each element of A

Example: in a five-spin system, the following call

 A=partner_state(spin_system,Template:'L+',2,{{{'E','Lz'},[1 3]}})

         will return the following state array

 A={state(spin_system,{'E' ,'L+','E' ,'E' ,'E'},{1 2 3 4 5}),...
    state(spin_system,{'Lz','L+','E' ,'E' ,'E'},{1 2 3 4 5}),...
    state(spin_system,{'E' ,'L+','Lz','E' ,'E'},{1 2 3 4 5}),...
    state(spin_system,{'Lz','L+','Lz','E' ,'E'},{1 2 3 4 5})};

         and the following descriptor array

    descr={{'E' ,'L+','E' ,'E' ,'E'},...
           {'Lz','L+','E' ,'E' ,'E'},...
           {'E' ,'L+','Lz','E' ,'E'},...
           {'Lz','L+','Lz','E' ,'E'}};

ilya.kuprov@weizmann.ac.il