cirq.ops.DepolarizingChannel

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A channel that depolarizes one or several qubits.

Inherits From: SupportsOnEachGate, Gate

View aliases

Main aliases

cirq.DepolarizingChannel, cirq.ops.common_channels.DepolarizingChannel

cirq.ops.DepolarizingChannel(
    p: float,
    n_qubits: int = 1
) -> None

Used in the notebooks

Used in the tutorials
Operators and observables Protocols

Args
p	The probability that one of the Pauli gates is applied. Each of the Pauli gates is applied independently with probability p / (4**n - 1).
n_qubits	the number of qubits.

Raises
ValueError	if p is not a valid probability.

Attributes
n_qubits	The number of qubits
p	The probability that one of the Pauli gates is applied. Each of the Pauli gates is applied independently with probability p / (4**n_qubits - 1).

Methods

controlled

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controlled(
    num_controls: int = None,
    control_values: Optional[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.

num_controls: Total number of control qubits. control_values: For which control qubit values to apply the sub gate. A sequence of length num_controls where each entry is an integer (or set of integers) corresponding to the qubit value (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.

num_qubits

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num_qubits() -> int

The number of qubits this gate acts on.

on

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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.

on_each

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

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

Args
*targets	The qubits to apply this gate to.

Returns
Operations applying this gate to the target qubits.

Raises
ValueError if targets are not instances of Qid or List[Qid]. ValueError if the gate operates on two or more Qids.

validate_args

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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 call super().validate_args(qubits) then do custom checks.

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

Throws:

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

with_probability

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

wrap_in_linear_combination

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wrap_in_linear_combination(
    coefficient: Union[complex, float, int] = 1
) -> "cirq.LinearCombinationOfGates"

__add__

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

__call__

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__call__(
    *args, **kwargs
)

Call self as a function.

__eq__

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__eq__(
    other: _SupportsValueEquality
) -> bool

__mul__

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__mul__(
    other: Union[complex, float, int]
) -> "cirq.LinearCombinationOfGates"

__ne__

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__ne__(
    other: _SupportsValueEquality
) -> bool

__neg__

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__neg__() -> "cirq.LinearCombinationOfGates"

__pow__

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__pow__(
    power
)

__rmul__

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__rmul__(
    other: Union[complex, float, int]
) -> "cirq.LinearCombinationOfGates"

__sub__

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

__truediv__

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__truediv__(
    other: Union[complex, float, int]
) -> "cirq.LinearCombinationOfGates"