cirq_superstaq.ops.qudit_gates

Attributes

`BSWAP`
`BSWAP_INV`
`CZ3`
`CZ3_INV`
`QutritZ0`
`QutritZ1`
`QutritZ2`
`SWAP3`

Classes

`BSwapPowGate`	iSWAP-like qutrit entangling gate swapping the "11" and "22" states of two qutrits.
`QubitSubspaceGate`	Embeds an n-qubit (i.e. SU(2^n)) gate into a given subspace of a higher-dimensional gate.
`QuditSwapGate`	A (non-parametrized) SWAP gate on two qudits of arbitrary dimension.
`QutritCZPowGate`	Generalized CZ gate for pairs of equal-dimension qudits.
`QutritZ0PowGate`	Phase rotation on the ground state of a qutrit.
`QutritZ1PowGate`	Phase rotation on the first excited state of a qutrit.
`QutritZ2PowGate`	Phase rotation on the second excited state of a qutrit.
`VirtualZPowGate`	Applies a phase rotation between two successive energy levels of a qudit.

Functions

`custom_resolver`(→ type[cirq.Gate] \| None)	Tells cirq.json how to deserialize cirq_superstaq's custom gates.
`qubit_subspace_op`(→ cirq.Operation)	Embeds a qubit Operation into a given subspace of a higher-dimensional Operation.
`qudit_swap_op`(→ cirq.Operation)	Construct a SWAP gate and apply it to the provided qudits.

Module Contents

class cirq_superstaq.ops.qudit_gates.BSwapPowGate(*, exponent: cirq.value.TParamVal = 1.0, global_shift: float = 0.0)

Bases: cirq.EigenGate, cirq.InterchangeableQubitsGate

iSWAP-like qutrit entangling gate swapping the “11” and “22” states of two qutrits.

property dimension: int

Indicates that this gate acts on qutrits.

Returns:: The integer 3, representing the qudit dimension for qutrits.

class cirq_superstaq.ops.qudit_gates.QubitSubspaceGate(sub_gate: cirq.Gate, qid_shape: collections.abc.Sequence[int], subspaces: collections.abc.Sequence[tuple[int, int]] | None = None)

Bases: cirq.Gate, cirq.InterchangeableQubitsGate

Embeds an n-qubit (i.e. SU(2^n)) gate into a given subspace of a higher-dimensional gate.

qubit_index_to_equivalence_group_key(index: int) → int

Check for interchangeable qubits.

Any interchangeable qubits in sub_gate will remain interchangeable in this gate if they have the same dimension and subspace.

property qid_shape: tuple[int, Ellipsis]

Specifies the qudit dimension for each of the inputs.

Returns:: The dimensions for the input qudits.

property sub_gate: cirq.Gate

The gate that is applied to the specified subspace.

Returns:: The underlying gate used.

property subspaces: list[tuple[int, int]]

A list of subspace indices acted upon.

For instance, a CX on the 0-1 qubit subspace of two qudits would have subspaces of [(0, 1), (0, 1)]. The same gate acting on the 1-2 subspaces of both qudits would correspond to [(1, 2), (1, 2)].

Returns:: A list of dimensions tuples, specified for each subspace.

class cirq_superstaq.ops.qudit_gates.QuditSwapGate(dimension: int)

Bases: cirq.Gate, cirq.InterchangeableQubitsGate

A (non-parametrized) SWAP gate on two qudits of arbitrary dimension.

property dimension: int

The qudit dimension on which this SWAP gate will act.

Returns:: The qudit dimension.

class cirq_superstaq.ops.qudit_gates.QutritCZPowGate(*, exponent: cirq.value.TParamVal = 1.0, global_shift: float = 0.0)

Bases: cirq.EigenGate, cirq.InterchangeableQubitsGate

Generalized CZ gate for pairs of equal-dimension qudits.

It is defined by the following unitary:

U = Σ_(i<d,j<d) ω**ij.|i⟩⟨i|.|j⟩⟨j|,

where d is the dimension of the qudits and ω = exp(2πi/d).

Currently written for qutrits (d = 3), but its implementation should work for any dimension.

property dimension: int

Indicates that this gate acts on qutrits.

Returns:: The integer 3, representing the qudit dimension for qutrits.

class cirq_superstaq.ops.qudit_gates.QutritZ0PowGate(*, exponent: cirq.value.TParamVal = 1.0, global_shift: float = 0.0)

Bases: _QutritZPowGate

Phase rotation on the ground state of a qutrit.

class cirq_superstaq.ops.qudit_gates.QutritZ1PowGate(*, exponent: cirq.value.TParamVal = 1.0, global_shift: float = 0.0)

Bases: _QutritZPowGate

Phase rotation on the first excited state of a qutrit.

class cirq_superstaq.ops.qudit_gates.QutritZ2PowGate(*, exponent: cirq.value.TParamVal = 1.0, global_shift: float = 0.0)

Bases: _QutritZPowGate

Phase rotation on the second excited state of a qutrit.

class cirq_superstaq.ops.qudit_gates.VirtualZPowGate(dimension: int = 2, level: int = 1, exponent: cirq.TParamVal = 1.0, global_shift: float = 0.0)

Bases: cirq.EigenGate

Applies a phase rotation between two successive energy levels of a qudit.

property dimension: int

The qudit dimension on which this gate acts.

Returns:: The gate’s dimension.

property level: int

The lowest energy level onto which this gate applies a phase; for example if level=2 a phase of (-1)**exponent will be applied to energy levels [2, …, dimension - 1]. This is equivalent to phase shifting all subsequent single-qudit gates acting in the (1, 2) subspace (assuming all other gates commute with this one).

Returns:: The lowest energy level onto which this gate applies a phase.

cirq_superstaq.ops.qudit_gates.custom_resolver(cirq_type: str) → type[cirq.Gate] | None

Tells cirq.json how to deserialize cirq_superstaq’s custom gates.

Changes to gate names in this file should be reflected in this resolver. See quantumai.google/cirq/dev/serialization for more information about (de)serialization.

Parameters:: cirq_type – The string of the gate type for the serializer to resolve.
Returns:: The resolved Cirq Gate matching the input, or None if no match.

cirq_superstaq.ops.qudit_gates.qubit_subspace_op(sub_op: cirq.Operation, qid_shape: collections.abc.Sequence[int], subspaces: collections.abc.Sequence[tuple[int, int]] | None = None) → cirq.Operation

Embeds a qubit Operation into a given subspace of a higher-dimensional Operation.

Uses QubitSubspaceGate.

Parameters:

sub_op – The cirq.Operation to embed.
qid_shape – The dimensions of the subspace.
subspaces – The list of all subspaces.

Returns:

A cirq.Operation embedding a low-dimensional operation.

Raises:

ValueError – If there is no gate specified for the subspace operation.

cirq_superstaq.ops.qudit_gates.qudit_swap_op(qudit0: cirq.Qid, qudit1: cirq.Qid) → cirq.Operation

Construct a SWAP gate and apply it to the provided qudits.

If both qudits have dimension 2, uses cirq.SWAP; otherwise uses QuditSwapGate.

Parameters:

qudit0 – The first qudit to swap.
qudit1 – The second qudit to swap.

Returns:

A SWAP gate acting on the provided qudits.

Raises:

ValueError – If the input qudits don’t have the same dimension.

cirq_superstaq.ops.qudit_gates.BSWAP

cirq_superstaq.ops.qudit_gates.BSWAP_INV

cirq_superstaq.ops.qudit_gates.CZ3

cirq_superstaq.ops.qudit_gates.CZ3_INV

cirq_superstaq.ops.qudit_gates.QutritZ0

cirq_superstaq.ops.qudit_gates.QutritZ1

cirq_superstaq.ops.qudit_gates.QutritZ2

cirq_superstaq.ops.qudit_gates.SWAP3