siGate

Inverse S gate

Since R2023a

Installation Required: This functionality requires MATLAB Support Package for Quantum Computing.

Syntax

g = siGate(targetQubit)

Description

g = siGate(targetQubit) applies an inverse S gate to a single target qubit and returns a quantum.gate.SimpleGate object.

If targetQubit is a vector of qubit indices, siGate returns a column vector of gates, where g(i) represents an inverse S gate applied to a qubit with index targetQubit(i).

Applying this gate is equivalent to applying an R1 gate with a rotation angle of –π/2, meaning that siGate(targetQubit) is equivalent to r1Gate(targetQubit,-pi/2).

Examples

Inverse S Gate and Its Matrix Representation

Create an inverse S gate that acts on a single qubit.

g = siGate(1)

g = 

  SimpleGate with properties:

             Type: "si"
    ControlQubits: [1×0 double]
     TargetQubits: 1
           Angles: [1×0 double]

Get the matrix representation of the gate.

M = getMatrix(g)

M =

   1.0000 + 0.0000i   0.0000 + 0.0000i
   0.0000 + 0.0000i   0.0000 - 1.0000i

Array of Inverse S Gates

Create an array of inverse S gates that act on qubits with indices 1 to 4.

g = siGate(1:4)

g = 

  4×1 SimpleGate array with gates:

    Id   Gate   Control   Target
     1   si               1     
     2   si               2     
     3   si               3     
     4   si               4     

Input Arguments

targetQubit — Target qubit of gate

positive integer scalar | positive integer vector

Target qubit of the gate, specified as a positive integer scalar index or vector of qubit indices.

Example: 1

Example: 3:5

More About

Matrix Representation of Inverse S Gate

The matrix representation of an inverse S gate applied to a single qubit is

$$\left[\begin{array}{cc}1& 0\\ 0& \exp \left(-i\frac{\pi }{2}\right)\end{array}\right]=\left[\begin{array}{cc}1& 0\\ 0& -i\end{array}\right].$$

Applying this gate is equivalent to applying an R1 gate with a rotation angle of –π/2. Applying the inverse S gate twice is equivalent to applying the Pauli Z gate.

Version History

Introduced in R2023a