cirq.Gate | Cirq | Google Quantum AI (original) (raw)

An operation type that can be applied to a collection of qubits.

Used in the notebooks

Used in the tutorials
Introduction to Cirq Custom gates Qudits Noisy Simulation

Gates can be applied to qubits by calling their on() method with the qubits to be applied to supplied, or, alternatively, by simply calling the gate on the qubits. In other words calling MyGate.on(q1, q2) to create an Operation on q1 and q2 is equivalent to MyGate(q1,q2).

Gates operate on a certain number of qubits. All implementations of gate must implement the num_qubits method declaring how many qubits they act on.

Linear combinations of gates can be created by adding gates together and multiplying them by scalars.

Methods

`controlled`

controlled(
    num_controls: Optional[int] = None,
    control_values: Optional[Union[cv.AbstractControlValues, Sequence[Union[int, Collection[int]]]]
        ] = None,
    control_qid_shape: Optional[Tuple[int, ...]] = None
) -> 'Gate'

Returns a controlled version of this gate. If no arguments are specified, defaults to a single qubit control.

Args
num_controls	Total number of control qubits.
control_values	Which control computational basis state to apply the sub gate. A sequence of length num_controls where each entry is an integer (or set of integers) corresponding to the computational basis state (or set of possible values) where that control is enabled. When all controls are enabled, the sub gate is applied. If unspecified, control values default to 1.
control_qid_shape	The qid shape of the controls. A tuple of the expected dimension of each control qid. Defaults to(2,) * num_controls. Specify this argument when using qudits.

Returns
A cirq.Gate representing self controlled by the given control values and qubits. This is a cirq.ControlledGate in the base implementation, but subclasses may return a different gate type.

`num_qubits`

num_qubits() -> int

The number of qubits this gate acts on.

`on`

on(
    *qubits
) -> 'Operation'

Returns an application of this gate to the given qubits.

Args
*qubits	The collection of qubits to potentially apply the gate to.

Returns: a cirq.Operation which is this gate applied to the given qubits.

`on_each`

on_each(
    *targets
) -> List['cirq.Operation']

Returns a list of operations applying the gate to all targets.

Args
*targets	The qubits to apply this gate to. For single-qubit gates this can be provided as varargs or a combination of nested iterables. For multi-qubit gates this must be provided as anIterable[Sequence[Qid]], where each sequence has num_qubitsqubits.

Returns
Operations applying this gate to the target qubits.

Raises
ValueError	If targets are not instances of Qid or Iterable[Qid]. If the gate qubit number is incompatible.
TypeError	If a single target is supplied and it is not iterable.

`validate_args`

validate_args(
    qubits: Sequence['cirq.Qid']
) -> None

Checks if this gate can be applied to the given qubits.

By default checks that:

inputs are of type Qid
len(qubits) == num_qubits()
qubit_i.dimension == qid_shape[i] for all qubits

Child classes can override. The child implementation should callsuper().validate_args(qubits) then do custom checks.

Args
qubits	The sequence of qubits to potentially apply the gate to.

Raises
ValueError	The gate can't be applied to the qubits.

`with_probability`

with_probability(
    probability: 'cirq.TParamVal'
) -> 'cirq.Gate'

Creates a probabilistic channel with this gate.

Args
probability	floating point value between 0 and 1, giving the probability this gate is applied.

Returns
cirq.RandomGateChannel that applies self with probabilityprobability and the identity with probability 1-p.

`wrap_in_linear_combination`

wrap_in_linear_combination(
    coefficient: 'cirq.TParamValComplex' = 1
) -> 'cirq.LinearCombinationOfGates'

Returns a LinearCombinationOfGates with this gate.

Args
coefficient	number coefficient to use in the resultingcirq.LinearCombinationOfGates object.

Returns
cirq.LinearCombinationOfGates containing self with a coefficient of coefficient.

`add`

__add__(
    other: Union['Gate', 'cirq.LinearCombinationOfGates']
) -> 'cirq.LinearCombinationOfGates'

`call`

__call__(
    *qubits, **kwargs
)

Call self as a function.

`mul`

__mul__(
    other: complex
) -> 'cirq.LinearCombinationOfGates'

`neg`

__neg__() -> 'cirq.LinearCombinationOfGates'

`pow`

__pow__(
    power
)

`rmul`

__rmul__(
    other: complex
) -> 'cirq.LinearCombinationOfGates'

`sub`

__sub__(
    other: Union['Gate', 'cirq.LinearCombinationOfGates']
) -> 'cirq.LinearCombinationOfGates'

`truediv`

__truediv__(
    other: complex
) -> 'cirq.LinearCombinationOfGates'