CSGate#

class qiskit.circuit.library.CSGate(label=None, ctrl_state=None)[source]#

Bases : ControlledGate

Controlled-S gate.

Can be applied to a QuantumCircuit with the cs() method.

Circuit symbol:

q_0: ──■──
     ┌─┴─┐
q_1: ┤ S ├
     └───┘

Matrix representation:

\[\begin{split}CS \ q_0, q_1 = I \otimes |0 \rangle\langle 0| + S \otimes |1 \rangle\langle 1| = \begin{pmatrix} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & i \end{pmatrix}\end{split}\]

Create new CS gate.

Attributes

condition_bits#: Get Clbits in condition.

ctrl_state#: Return the control state of the gate as a decimal integer.

decompositions#: Get the decompositions of the instruction from the SessionEquivalenceLibrary.

definition#: Return definition in terms of other basic gates. If the gate has open controls, as determined from self.ctrl_state, the returned definition is conjugated with X without changing the internal _definition.

duration#: Get the duration.

label#: Return instruction label

name#

Get name of gate. If the gate has open controls the gate name will become:

<original_name_o<ctrl_state>

where <original_name> is the gate name for the default case of closed control qubits and <ctrl_state> is the integer value of the control state for the gate.

num_clbits#: Return the number of clbits.

num_ctrl_qubits#

Get number of control qubits.

Renvoie:: The number of control qubits for the gate.
Type renvoyé:: int

num_qubits#: Return the number of qubits.

params#

Get parameters from base_gate.

Renvoie:: List of gate parameters.
Type renvoyé:: list
Lève:: CircuitError – Controlled gate does not define a base gate

unit#: Get the time unit of duration.

Methods

inverse()[source]#: Return inverse of CSGate (CSdgGate).

power(exponent)[source]#

Raise gate to a power.