quchip.devices.spaces

Backend-neutral local Hilbert spaces and their named operators.

Classes

ChargeSpace(num_basis)	Finite integer-charge basis centered on zero charge.
CustomSpace(dimension, operators)	Named local operators supplied as matrices or zero-argument JAX callables.
FockSpace(levels)	Finite Fock ladder with standard bosonic and qubit operators.
LocalSpace()	Numerical realization of the operators used by one device model.
PhaseGridSpace(points, extent)	Uniform endpoint-excluded phase grid with nonperiodic finite differences.
TruncationBoundary(indices, description, ...)	Authored basis indices near a cutoff and the corresponding convergence check.

class quchip.devices.spaces.TruncationBoundary(indices, description, convergence_hint)

Bases: object

Authored basis indices near a cutoff and the corresponding convergence check.

Parameters:

• indices (tuple[int, ...]) – Distinct non-negative boundary indices.

• description (str) – Human-readable boundary name.

• convergence_hint (str) – Suggested convergence comparison.

indices: tuple[int, ...]

description: str

convergence_hint: str

class quchip.devices.spaces.LocalSpace

Bases: ABC

Numerical realization of the operators used by one device model.

abstract property dimension: int

Return the authored local-space dimension.

abstractmethod matrix(name)

Return one named operator as a JAX-compatible dense array.

Parameters:

name (str) – Operator name supported by the concrete space.

truncation_boundary()

Describe a cutoff, or return None for an intrinsically finite space.

operator(name, backend)

Lower one named local operator through backend.

Parameters:

• name (str) – Supported local operator name.

• backend (backend protocol) – Object that supplies native operator constructors.

class quchip.devices.spaces.FockSpace(levels)

Bases: LocalSpace

Finite Fock ladder with standard bosonic and qubit operators.

Parameters:

levels (int) – Hilbert-space dimension, at least 2. The a ladder is truncated at levels - 1.

levels: int

truncation_boundary()

Describe a cutoff, or return None for an intrinsically finite space.

property dimension: int

Return the authored local-space dimension.

matrix(name)

Return a named charge-space matrix.

Parameters:

name ({"n", "cos_phi", "sin_phi", "I"}) – Operator to construct.

operator(name, backend)

Lower one named local operator through backend.

Parameters:

• name (str) – Supported local operator name.

• backend (backend protocol) – Object that supplies native operator constructors.

class quchip.devices.spaces.ChargeSpace(num_basis)

Bases: LocalSpace

Finite integer-charge basis centered on zero charge.

Parameters:

num_basis (int) – Odd basis size, at least 3, with charges from -(num_basis-1)//2 to +(num_basis-1)//2.

num_basis: int

truncation_boundary()

Describe a cutoff, or return None for an intrinsically finite space.

property dimension: int

Return the authored local-space dimension.

matrix(name)

Return a named phase-grid matrix.

Parameters:

name ({"phi", "n", "n2", "cos_phi", "sin_phi", "I"}) – Operator to construct.

class quchip.devices.spaces.PhaseGridSpace(points, extent)

Bases: LocalSpace

Uniform endpoint-excluded phase grid with nonperiodic finite differences.

The centered-difference stencil does not wrap across the grid boundary. Values beyond each endpoint are zero. :param points: Number of endpoint-excluded grid points, at least 3. :type points: int :param extent: Positive half-width of the grid, in dimensionless phase radians. :type extent: float

points: int

extent: float

truncation_boundary()

Describe a cutoff, or return None for an intrinsically finite space.

property dimension: int

Return the authored local-space dimension.

matrix(name)

Return one custom operator matrix.

Parameters:

name (str) – Key in operators.

class quchip.devices.spaces.CustomSpace(dimension, operators)

Bases: LocalSpace

Named local operators supplied as matrices or zero-argument JAX callables.

Parameters:

• dimension (int) – Positive matrix dimension.

• operators (mapping[str, array or callable]) – Operator providers. Each resulting matrix needs shape (dimension, dimension).

property dimension: int

Return the authored local-space dimension.

matrix(name)

Return one named operator as a JAX-compatible dense array.

Parameters:

name (str) – Operator name supported by the concrete space.