A Lesson On Single-Qubit Quantum Gates (Part 2)

Learn about all the important Phase gates used in Quantum algorithms in this lesson.

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We discussed the Identity, Pauli, and Hadamard gates in last week's lesson.

This week, we will move forward and learn about Phase gates.

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In case you missed the previous lessons on Quantum gates, here are the links for them:

A Deep Dive Into The Mathematics Of Quantum Gates

A Lesson On Pauli Matrices As Quantum Gates

A Lesson On Single-Qubit Quantum Gates (Part 1)

Let’s get started!

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4. Phase Gates

These are quantum gates that act to change the phase of a qubit’s state without changing its probabilities.

These gates apply a relative phase shift to the qubit's state.

The general form of a phase gate is represented by the following matrix:

This tells that a phase gate applies a phase e^(iθ) to |1> component of a qubit, while leaving the |0> component unchanged.

The following phase gates are important to know about:

1. Z gate

2. S gate

3. S† gate

4. T gate

5. T† gate

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Z gate