Book Image

Quantum Computing in Practice with Qiskit® and IBM Quantum Experience®

By : Hassi Norlen
5 (1)
Book Image

Quantum Computing in Practice with Qiskit® and IBM Quantum Experience®

5 (1)
By: Hassi Norlen

Overview of this book

IBM Quantum Experience® is a leading platform for programming quantum computers and implementing quantum solutions directly on the cloud. This book will help you get up to speed with programming quantum computers and provide solutions to the most common problems and challenges. You’ll start with a high-level overview of IBM Quantum Experience® and Qiskit®, where you will perform the installation while writing some basic quantum programs. This introduction puts less emphasis on the theoretical framework and more emphasis on recent developments such as Shor’s algorithm and Grover’s algorithm. Next, you’ll delve into Qiskit®, a quantum information science toolkit, and its constituent packages such as Terra, Aer, Ignis, and Aqua. You’ll cover these packages in detail, exploring their benefits and use cases. Later, you’ll discover various quantum gates that Qiskit® offers and even deconstruct a quantum program with their help, before going on to compare Noisy Intermediate-Scale Quantum (NISQ) and Universal Fault-Tolerant quantum computing using simulators and actual hardware. Finally, you’ll explore quantum algorithms and understand how they differ from classical algorithms, along with learning how to use pre-packaged algorithms in Qiskit® Aqua. By the end of this quantum computing book, you’ll be able to build and execute your own quantum programs using IBM Quantum Experience® and Qiskit® with Python.
Table of Contents (12 chapters)

Creating superpositions with the H gate

Now, let's revisit our old friend from Chapter 4, Starting at the Ground Level with Terra, the Hadamard or H gate. This is a fairly specialized gate that we can use to make a generic qubit superposition. But there's more to it than that; we can also make use of the H gate to change the axis of measurement from the generic z (or computational) axis to the x axis to gain additional insights into the qubit behavior. More on that in the There's more section.

The H gate can be expressed as the following unitary matrix:

Unless you are really good at interpreting matrix operations, it might not be entirely clear just what this gate will do with your qubits. If we describe the behavior as a combination of 2 qubit rotations instead, things might become clearer. When you apply the Hadamard gate to your qubit, you run it through two rotations: first a rotation around the y axis, and then a rotation around the...