Part 3. Quantum algorithms and code

Ultimately, developers write code that fixes problems. Now that we have explained the core ideas and fundamental concepts, it is time to see how traditional software problems can benefit from them.

Chapter 7 dives deeper into the HelloStrange example introduced in chapter 2. We study the example as part of a software application that uses quantum computing, bringing it closer to the daily work environment of a developer. In chapter 8, we implement an algorithm that allows for secure communication using quantum computing. The implementation is written in Java, and it can be used in many existing communication libraries. Next, in chapter 9, we create an implementation of the Deutsch-Jozsa algorithm, which is well known in the quantum computing field. Although the direct practical relevance of this algorithm is limited, the concept is important: it gives us an idea about what parts of typical applications may benefit from using quantum computing. Chapter 10 introduces Grover’s search algorithm. In this chapter, we also look in detail at a quantum oracle and explain how it relates to classical black box functions. Finally, in chapter 11, we show a Java implementation of Shor’s algorithm, which is one of the most famous quantum algorithms: it allows us to factor large integer numbers much faster than a classical algorithm can.