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)

Understanding your circuits by using the unitary simulator

As it turns out, any valid quantum circuit that consists only of gates can be translated into a unitary matrix that describes the expected outcome for each possible state vector input. As you have seen in Chapter 2, Quantum Computing and Qubits with Python, each quantum gate is in itself a unitary matrix, and the combination of the unitaries that make up the complete quantum circuit can in itself be described as a unitary.

Qiskit® lets you use the Qiskit Aer unitary_simulator simulator to return the unitary matrix that corresponds with your quantum circuit. You run the job just like you would for qasm_simulator jobs.

When running unitary_simulator, you only run the circuit once. We can then use the get_unitary(qc) method on the returned results to see the unitary as a matrix for a circuit, such as this one-qubit superposition circuit using a Hadamard gate:

Figure 7.16 – Quantum circuit...