carrier.m

Returns the "carrier" Hamiltonian - the part of the Zeeman interaction Hamiltonian that corresponds to all particles having the Zeeman frequency prescribed by their free particle magnetogyric ratio and the magnet field specified by the user. This Hamiltonian is frequently used in rotating frame transformations.

Syntax

    H=carrier(spin_system,spins,operator_type)

Parameters

    spins - a string specifying the isotope, e.g. '1H';
            to select all spins, use 'all'.

    in Liouville space, operator_type can be set to

          'left' - produces left side product superoperator

         'right' - produces right side product superoperator

          'comm' - produces commutation superoperator (default)

         'acomm' - produces anticommutation superoperator

    in Hilbert space this parameter is ignored.

Outputs

    H - a Hamiltonian (Hilbert space) or its superoperator 
        of the specified type (Liouville space).

Examples

Carrier Hamiltonians are used in rotating frame transformations (using rotframe.m) because they are normally the largest and the simplest (just a sum of Lz) part of any magnetic resonance Hamiltonian. Relevant calls may be seen in the source code of Spinach context functions (crystal.m, powder.m, singlerot.m, and others) as well as in the code of any functions that perform rotating frame transformations as a part of their housekeeping (e.g. fieldsweep.m and rapidscan.m).

Notes

A carrier Hamiltonian is not the same as Zeeman Hamiltonian - it does not contain chemical shift or g-tensor information and should not therefore be used to create field gradient operators. To get the Zeeman part of the Hamiltonian, call hamiltonian.m with the corresponding option. For an example of how to do that see the source code of g2fplanck.m.

See also

rotframe.m, hamiltonian.m, operator.m, intrep.m, crystal.m, powder.m, singlerot.m, fieldsweep.m, rapidscan.m, g2fplanck.m, average.m, frqoffset.m, Kernel_functions

Version 2.4, authors: Ilya Kuprov