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)

Adding more qubits to the Grover search

So far, we have done reasonably well in our Grover coding. We built our two and three qubit circuits using unique Qiskit® gates for the number of qubits that our circuits contained: CX and CCX. For a four qubit and more Grover, we will use a multi-control NOT gate, MCX, to dynamically create the right number of control inputs.

Getting ready

We will use the same sample functions as in the Building the Grover's search algorithm recipe.

For two and three qubit Grovers, we could use the prefabricated CX and CCX gates to create our oracle and amplifier circuits. As we are using the same model to build a four and more qubit Grover, instead of using CCCX, CCCCX gates, and more, we use the MCX gate in our circuit, to let Qiskit® build the gate logic behind the scenes.

Note

To understand what we are doing here, take a look back at Chapter 6, Understanding the Qiskit® Gate Library, specifically at the CX and CCX gates...