BosonSpace

class qugradlab.hilbert_spaces.bosonic.BosonSpace(n_single_particle_states: int, truncation_level: int)

Bases: HilbertSpace

Represents a truncated Fock space of boson modes.

Attributes

basis	An array of positive integers labeling the Hilbert space basis
dim	The Hilbert space dimension
inverse	An array satisfying the property self.inverse[self.basis[i]]=i
n_single_particle_states	The number of single particle states
truncation_level	The maximum number of bosons per single particle state

Methods

__init__	Initialises a BosonSpace
basis_vector	Returns a column vector represnetation corresponding to the input basis state label.
get_subspace	Generates a new subspace by filtering the basis state labels.
labels	Generates a string (list of strings) that represent the state(s).

__init__(n_single_particle_states: int, truncation_level: int)

Initialises a BosonSpace

Parameters:

• n_single_particle_states (int) – The number of single particle states

• truncation_level (int) – The maximum number of bosons per single particle state

basis_vector(basis_state_label: int) → ndarray[complex128]

Returns a column vector represnetation corresponding to the input basis state label.

Parameters:

basis_state_label (int) – A positive integer denoting the label of the basis state to generate the basis vector for.

Returns:

The basis vector corresponding to the input basis state label.

Return type:

NDArray[Shape[dim], np.complex128]

get_subspace(filter: ndarray[bool]) → HilbertSpace

Generates a new subspace by filtering the basis state labels.

Parameters:

filter (NDArray[Shape[dim], bool]) – True entries are retained in the new subspace.

Returns:

The filtered subspace.

Return type:

HilbertSpace

labels(states: int | list[int] | None = None) → str | list[str]

Generates a string (list of strings) that represent the state(s).

Parameters:

states (int | list[int], optional) – The state(s) to label. If None then the labels for all states in basis are returned. By default None.

Returns:

The label(s) for the specified states.

Return type:

str | list[str]

property basis: ndarray[int]

An array of positive integers labeling the Hilbert space basis

property dim

The Hilbert space dimension

property inverse: ndarray[int]

An array satisfying the property self.inverse[self.basis[i]]=i

property n_single_particle_states: int

The number of single particle states

property truncation_level: int

The maximum number of bosons per single particle state