Create.m

The entry function of the Spinach kernel that creates the spin system object that the rest of the library requires to run. It checks and absorbs interaction specifications, and writes some useful diagnostics to the console.

Bosonic modes - electromagnetic cavities, phonon modes, and transmons - are declared in sys.isotopes and parameterised in the inter.modes input block, which is validated and absorbed by this function; see the bosonic modes section of the spin system specification. Console summaries of mode parameters, mode couplings, and spin Hamiltonian modulation are printed as the block is ingested.

Syntax

    spin_system=create(sys,inter)

Parameters

   sys   - spin system and instrument specification
           structure, see the spin system specification
           section of the online manual

 inter   - interaction specification structure, see
           see the spin system specification section
           of the online manual

Outputs

 spin_system   - the primary object used by Spinach
                 to store simulation information

Examples

A simple spin system specification followed by a call to create.m appears below. There are hundreds of further examples in the example set.

    % Set the spin system
    sys.isotopes={'1H','1H'};
    inter.zeeman.scalar={0.0 0.0};
    inter.coordinates={[0.00 0.00 0.00];
                       [0.00 0.00 2.00]};
     
    % Magnet field
    sys.magnet=14.1;

    % Spinach housekeeping
    spin_system=create(sys,inter);

Notes

1. inter.modes.carriers declares, for each bosonic mode, the laboratory frequency of the rotating frame in which inter.modes.frqs is specified; declared frequencies are then detunings and may be negative, and thermal occupations are computed from the physical frequency, meaning the sum of the carrier and the detuning.
2. inter.modes.t2_times is interpreted at the declared temperature: the pure dephasing rate is extracted as 1/T2-kappa*(1+2*nbar)/2, where kappa is the amplitude damping rate and nbar the thermal occupation at the physical mode frequency.
3. Quadrature operators of bosonic modes follow the (a+a')/sqrt(2) normalisation everywhere, in inter.modes.longitudinal as well as in the modulation channels.
4. inter.temperature must be specified when any bosonic mode is damped; the room temperature default is refused, with an error message naming the thermal occupation that it would have implied.

See also

basis.m, assume.m, operator.m, state.m, hamiltonian.m, reduce.m, thermalize.m, device.m, coherent.m, rlx_modes.m, cart2mode.m, ejec2duffing.m, Kernel_functions

Version 2.4, authors: Ilya Kuprov, Hannah Hogben, Konstantin Pervushin, Luke Edwards