Fock

This module contains functions for performing calculations on Fock states.

Functions

U_to_choi(U[, Udual])	Converts a unitary transformation to a Choi tensor.
apply_choi_to_dm(choi, dm, choi_in_modes[, ...])	Applies a choi operator to a density matrix.
apply_choi_to_ket(choi, ket, choi_in_modes)	Applies a choi operator to a ket.
apply_kraus_to_dm(kraus, dm, kraus_in_modes)	Applies a kraus operator to a density matrix.
apply_kraus_to_ket(kraus, ket, kraus_in_modes)	Applies a kraus operator to a ket.
autocutoffs(cov, means, probability)	Returns the cutoffs of a Gaussian state by computing the 1-mode marginals until the probability of the marginal is less than probability.
beamsplitter(*args, **kwargs)
contract_states(stateA, stateB, a_is_dm, ...)	Contracts two states in the specified modes.
displacement(*args, **kwargs)
dm_to_ket(dm)	Maps a density matrix to a ket if the state is pure.
dm_to_probs(dm)	Extracts the diagonals of a density matrix.
estimate_dx(cutoff[, period_resolution])	Estimates a suitable quadrature discretization interval dx.
estimate_quadrature_axis(cutoff[, minimum, ...])	Generates a suitable quadrature axis.
estimate_xmax(cutoff[, minimum])	Estimates a suitable quadrature axis length
fidelity(state_a, state_b, a_ket, b_ket)	Computes the fidelity between two states in Fock representation.
fock_state(n)	Returns a pure or mixed Fock state.
is_mixed_dm(dm)	Evaluates if a density matrix represents a mixed state.
ket_to_dm(ket)	Maps a ket to a density matrix.
ket_to_probs(ket)	Maps a ket to probabilities.
lru_cache([maxsize, typed])	Least-recently-used cache decorator.
norm(state, is_dm)	Returns the norm of a ket or the trace of the density matrix.
normalize(fock, is_dm)	Returns the normalized ket state.
number_means(tensor, is_dm)	Returns the mean of the number operator in each mode.
number_variances(tensor, is_dm)	Returns the variance of the number operator in each mode.
oscillator_eigenstate(q, cutoff)	Harmonic oscillator eigenstate wavefunction psi_n(q) = <n|q>.
purity(dm)	Returns the purity of a density matrix.
quadrature_distribution(state[, ...])	Given the ket or density matrix of a single-mode state, it generates the probability density distribution \(\tr [ \rho |x_\phi><x_\phi| ]\) where rho is the density matrix of the state and |x_phi> the quadrature eigenvector with angle phi equal to quadrature_angle.
sample_homodyne(state[, quadrature_angle])	Given a single-mode state, it generates the pdf of \(\tr [ \rho |x_\phi><x_\phi| ]\) where rho is the reduced density matrix of the state.
squeezed(*args, **kwargs)
squeezer(*args, **kwargs)
tensor_int_cache(fn)	Decorator function to cache functions with a 1D Tensor (Vector) and int as arguments, that is, functions with signature func(x: Vector, n: int).
trace(dm, keep)	Computes the partial trace of a density matrix.
validate_contraction_indices(in_idx, ...)	Validates the indices used for the contraction of a tensor.
wigner_to_bargmann_Choi(X, Y, d)	Converts the wigner representation in terms of covariance matrix and mean vector into the Bargmann A,B,C triple for a channel (i.e. for M modes, A has shape 4M x 4M and B has shape 4M).
wigner_to_bargmann_U(X, d)	Converts the wigner representation in terms of covariance matrix and mean vector into the Bargmann A,B,C triple for a unitary (i.e. for M modes, A has shape 2M x 2M and B has shape 2M).
wigner_to_bargmann_psi(cov, means)	Converts the wigner representation in terms of covariance matrix and mean vector into the Bargmann A,B,C triple for a Hilbert vector (i.e. for M modes, A has shape M x M and B has shape M).
wigner_to_bargmann_rho(cov, means)	Converts the wigner representation in terms of covariance matrix and mean vector into the Bargmann A,B,C triple for a density matrix (i.e. for M modes, A has shape 2M x 2M and B has shape 2M).
wigner_to_fock_Choi(X, Y, d, shape)	Returns the Fock representation of a Gaussian Choi matrix.
wigner_to_fock_U(X, d, shape)	Returns the Fock representation of a Gaussian unitary transformation.
wigner_to_fock_state(cov, means, shape[, ...])	Returns the Fock representation of a Gaussian state.

Variables

List	A generic version of list.
Optional	Optional type.
SQRT	ndarray(shape, dtype=float, buffer=None, offset=0,
Scalar	alias of Union[R, C, Z, N]
Sequence	A generic version of collections.abc.Sequence.
Tuple	Tuple type; Tuple[X, Y] is the cross-product type of X and Y.
math	A class to manage the different backends supported by Mr Mustard.
settings	A class containing various settings that are used by Mr Mustard throughout a session.

code/physics/fock

 

Download Python script

 

Download Notebook

 

View on GitHub