Ejemplo n.º 1
0
def floquet_markov_mesolve(R,
                           ekets,
                           rho0,
                           tlist,
                           e_ops,
                           f_modes_table=None,
                           options=None,
                           floquet_basis=True):
    """
    Solve the dynamics for the system using the Floquet-Markov master equation.
    """

    if options is None:
        opt = Options()
    else:
        opt = options

    if opt.tidy:
        R.tidyup()

    #
    # check initial state
    #
    if isket(rho0):
        # Got a wave function as initial state: convert to density matrix.
        rho0 = ket2dm(rho0)

    #
    # prepare output array
    #
    n_tsteps = len(tlist)
    dt = tlist[1] - tlist[0]

    output = Result()
    output.solver = "fmmesolve"
    output.times = tlist

    if isinstance(e_ops, FunctionType):
        n_expt_op = 0
        expt_callback = True

    elif isinstance(e_ops, list):

        n_expt_op = len(e_ops)
        expt_callback = False

        if n_expt_op == 0:
            output.states = []
        else:
            if not f_modes_table:
                raise TypeError("The Floquet mode table has to be provided " +
                                "when requesting expectation values.")

            output.expect = []
            output.num_expect = n_expt_op
            for op in e_ops:
                if op.isherm:
                    output.expect.append(np.zeros(n_tsteps))
                else:
                    output.expect.append(np.zeros(n_tsteps, dtype=complex))

    else:
        raise TypeError("Expectation parameter must be a list or a function")

    #
    # transform the initial density matrix to the eigenbasis: from
    # computational basis to the floquet basis
    #
    if ekets is not None:
        rho0 = rho0.transform(ekets)

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full())
    r = scipy.integrate.ode(cy_ode_rhs)
    r.set_f_params(R.data.data, R.data.indices, R.data.indptr)
    r.set_integrator('zvode',
                     method=opt.method,
                     order=opt.order,
                     atol=opt.atol,
                     rtol=opt.rtol,
                     max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])

    #
    # start evolution
    #
    rho = Qobj(rho0)

    t_idx = 0
    for t in tlist:
        if not r.successful():
            break

        rho = Qobj(vec2mat(r.y), rho0.dims, rho0.shape)

        if expt_callback:
            # use callback method
            if floquet_basis:
                e_ops(t, Qobj(rho))
            else:
                f_modes_table_t, T = f_modes_table
                f_modes_t = floquet_modes_t_lookup(f_modes_table_t, t, T)
                e_ops(t, Qobj(rho).transform(f_modes_t, True))
        else:
            # calculate all the expectation values, or output rho if
            # no operators
            if n_expt_op == 0:
                if floquet_basis:
                    output.states.append(Qobj(rho))
                else:
                    f_modes_table_t, T = f_modes_table
                    f_modes_t = floquet_modes_t_lookup(f_modes_table_t, t, T)
                    output.states.append(Qobj(rho).transform(f_modes_t, True))
            else:
                f_modes_table_t, T = f_modes_table
                f_modes_t = floquet_modes_t_lookup(f_modes_table_t, t, T)
                for m in range(0, n_expt_op):
                    output.expect[m][t_idx] = \
                        expect(e_ops[m], rho.transform(f_modes_t, False))

        r.integrate(r.t + dt)
        t_idx += 1

    return output
Ejemplo n.º 2
0
def floquet_markov_mesolve(R, ekets, rho0, tlist, e_ops, f_modes_table=None,
                           options=None, floquet_basis=True):
    """
    Solve the dynamics for the system using the Floquet-Markov master equation.
    """

    if options is None:
        opt = Options()
    else:
        opt = options

    if opt.tidy:
        R.tidyup()

    #
    # check initial state
    #
    if isket(rho0):
        # Got a wave function as initial state: convert to density matrix.
        rho0 = ket2dm(rho0)

    #
    # prepare output array
    #
    n_tsteps = len(tlist)
    dt = tlist[1] - tlist[0]

    output = Result()
    output.solver = "fmmesolve"
    output.times = tlist

    if isinstance(e_ops, FunctionType):
        n_expt_op = 0
        expt_callback = True

    elif isinstance(e_ops, list):

        n_expt_op = len(e_ops)
        expt_callback = False

        if n_expt_op == 0:
            output.states = []
        else:
            if not f_modes_table:
                raise TypeError("The Floquet mode table has to be provided " +
                                "when requesting expectation values.")

            output.expect = []
            output.num_expect = n_expt_op
            for op in e_ops:
                if op.isherm:
                    output.expect.append(np.zeros(n_tsteps))
                else:
                    output.expect.append(np.zeros(n_tsteps, dtype=complex))

    else:
        raise TypeError("Expectation parameter must be a list or a function")

    #
    # transform the initial density matrix to the eigenbasis: from
    # computational basis to the floquet basis
    #
    if ekets is not None:
        rho0 = rho0.transform(ekets)

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full())
    r = scipy.integrate.ode(cy_ode_rhs)
    r.set_f_params(R.data.data, R.data.indices, R.data.indptr)
    r.set_integrator('zvode', method=opt.method, order=opt.order,
                     atol=opt.atol, rtol=opt.rtol, max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])

    #
    # start evolution
    #
    rho = Qobj(rho0)

    t_idx = 0
    for t in tlist:
        if not r.successful():
            break

        rho.data = vec2mat(r.y)

        if expt_callback:
            # use callback method
            if floquet_basis:
                e_ops(t, Qobj(rho))
            else:
                f_modes_table_t, T = f_modes_table
                f_modes_t = floquet_modes_t_lookup(f_modes_table_t, t, T)
                e_ops(t, Qobj(rho).transform(f_modes_t, True))
        else:
            # calculate all the expectation values, or output rho if
            # no operators
            if n_expt_op == 0:
                if floquet_basis:
                    output.states.append(Qobj(rho))
                else:
                    f_modes_table_t, T = f_modes_table
                    f_modes_t = floquet_modes_t_lookup(f_modes_table_t, t, T)
                    output.states.append(Qobj(rho).transform(f_modes_t, True))
            else:
                f_modes_table_t, T = f_modes_table
                f_modes_t = floquet_modes_t_lookup(f_modes_table_t, t, T)
                for m in range(0, n_expt_op):
                    output.expect[m][t_idx] = \
                        expect(e_ops[m], rho.transform(f_modes_t, False))

        r.integrate(r.t + dt)
        t_idx += 1

    return output