qiskit.circuit.library.PhaseGate

class PhaseGate(theta, label=None)

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Single-qubit rotation about the Z axis.

This is a diagonal gate. It can be implemented virtually in hardware via framechanges (i.e. at zero error and duration).

Circuit symbol:

     ┌──────┐
q_0: ┤ P(λ) ├
     └──────┘

Matrix Representation:

\begin{split}P(\lambda) = \begin{pmatrix} 1 & 0 \\ 0 & e^{i\lambda} \end{pmatrix}\end{split}

Examples:

$P(\lambda = \pi) = Z$ $P(\lambda = \pi/2) = S$ $P(\lambda = \pi/4) = T$

init

__init__(theta, label=None)

Create new Phase gate.

Methods


`__init__`(theta[, label])	Create new Phase gate.
`add_decomposition`(decomposition)	Add a decomposition of the instruction to the SessionEquivalenceLibrary.
`assemble`()	Assemble a QasmQobjInstruction
`broadcast_arguments`(qargs, cargs)	Validation and handling of the arguments and its relationship.
`c_if`(classical, val)	Add classical condition on register classical and value val.
`control`([num_ctrl_qubits, label, ctrl_state])	Return a (mutli-)controlled-Phase gate.
`copy`([name])	Copy of the instruction.
`inverse`()	Return inverted Phase gate ( $Phase(\lambda){\dagger} = Phase(-\lambda)$ )
`is_parameterized`()	Return True .IFF.
`mirror`()	DEPRECATED: use instruction.reverse_ops().
`power`(exponent)	Creates a unitary gate as gate^exponent.
`qasm`()	Return a default OpenQASM string for the instruction.
`repeat`(n)	Creates an instruction with gate repeated n amount of times.
`reverse_ops`()	For a composite instruction, reverse the order of sub-instructions.
`to_matrix`()	Return a numpy.array for the Phase gate.
`validate_parameter`(parameter)	Gate parameters should be int, float, or ParameterExpression

Attributes


`decompositions`	Get the decompositions of the instruction from the SessionEquivalenceLibrary.
`definition`	Return definition in terms of other basic gates.
`duration`	Get the duration.
`label`	Return gate label
`params`	return instruction params.
`unit`	Get the time unit of duration.

add_decomposition

add_decomposition(decomposition)

Add a decomposition of the instruction to the SessionEquivalenceLibrary.

assemble

assemble()

Assemble a QasmQobjInstruction

Return type

Instruction

broadcast_arguments

broadcast_arguments(qargs, cargs)

Validation and handling of the arguments and its relationship.

For example, cx([q[0],q[1]], q[2]) means cx(q[0], q[2]); cx(q[1], q[2]) . This method yields the arguments in the right grouping. In the given example:

in: [[q[0],q[1]], q[2]],[]
outs: [q[0], q[2]], []
      [q[1], q[2]], []

The general broadcasting rules are:

If len(qargs) == 1:
```
[q[0], q[1]] -> [q[0]],[q[1]]
```

If len(qargs) == 2:

[[q[0], q[1]], [r[0], r[1]]] -> [q[0], r[0]], [q[1], r[1]]
[[q[0]], [r[0], r[1]]]       -> [q[0], r[0]], [q[0], r[1]]
[[q[0], q[1]], [r[0]]]       -> [q[0], r[0]], [q[1], r[0]]

If len(qargs) >= 3:

[q[0], q[1]], [r[0], r[1]],  ...] -> [q[0], r[0], ...], [q[1], r[1], ...]

Parameters

qargs (List) – List of quantum bit arguments.
cargs (List) – List of classical bit arguments.

Return type

Tuple [List, List]

Returns

A tuple with single arguments.

Raises

CircuitError - If the input is not valid. For example, the number of arguments does not match the gate expectation.

c_if

c_if(classical, val)

Add classical condition on register classical and value val.

control

control(num_ctrl_qubits=1, label=None, ctrl_state=None)

Return a (mutli-)controlled-Phase gate.

Parameters

num_ctrl_qubits (int) – number of control qubits.
label (str or None) – An optional label for the gate [Default: None]
ctrl_state (int or str or None) – control state expressed as integer, string (e.g. ‘110’), or None. If None, use all 1s.

Returns

controlled version of this gate.

Return type

ControlledGate

copy

copy(name=None)

Copy of the instruction.

Parameters

name (str) - name to be given to the copied circuit, if None then the name stays the same.

Returns

a copy of the current instruction, with the name

updated if it was provided

Return type

qiskit.circuit.Instruction

decompositions

Get the decompositions of the instruction from the SessionEquivalenceLibrary.

definition

Return definition in terms of other basic gates.

duration

Get the duration.

inverse

inverse()

Phase(\lambda){\dagger} = Phase(-\lambda)

is_parameterized

is_parameterized()

Return True .IFF. instruction is parameterized else False

label

Return gate label

Return type

str

mirror

mirror()

DEPRECATED: use instruction.reverse_ops().

Returns

a new instruction with sub-instructions

reversed.

Return type

qiskit.circuit.Instruction

params

return instruction params.

power

power(exponent)

Creates a unitary gate as gate^exponent.

Parameters

exponent (float) - Gate^exponent

Returns

To which to_matrix is self.to_matrix^exponent.

Return type

qiskit.extensions.UnitaryGate

Raises

CircuitError - If Gate is not unitary

qasm

qasm()

Return a default OpenQASM string for the instruction.

Derived instructions may override this to print in a different format (e.g. measure q[0] -> c[0];).

repeat

repeat(n)

Creates an instruction with gate repeated n amount of times.

Parameters

n (int) - Number of times to repeat the instruction

Returns

Containing the definition.

Return type

qiskit.circuit.Instruction

Raises

CircuitError - If n < 1.

reverse_ops

reverse_ops()

For a composite instruction, reverse the order of sub-instructions.

This is done by recursively reversing all sub-instructions. It does not invert any gate.

Returns

a new instruction with

sub-instructions reversed.

Return type

qiskit.circuit.Instruction

to_matrix

to_matrix()

Return a numpy.array for the Phase gate.

unit

Get the time unit of duration.

validate_parameter

validate_parameter(parameter)

Gate parameters should be int, float, or ParameterExpression

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