1 Introducing quantum computing


This chapter covers

  • Why people are excited about quantum computing
  • What a quantum computer is
  • What a quantum computer can and cannot do
  • How quantum computers relate to classical programming

Quantum computing has been an increasingly popular research field and source of hype over the last few years. By using quantum physics to perform computation in new and wonderful ways, quantum computers can impact society, making it an exciting time to get involved and learn how to program quantum computers and apply quantum resources to solve problems that matter.

In all the buzz about the advantages quantum computing offers, however, it is easy to lose sight of the real scope of those benefits. We have some interesting historical precedent for what can happen when promises about a technology outpace reality. In the 1970s, machine learning and artificial intelligence suffered from dramatically reduced funding, as the hype and excitement around AI outstripped its results; this would later be called the “AI winter.” Similarly, internet companies faced the same danger when trying to overcome the dot-com bust.

One way forward is to critically understand the promise offered by quantum computing, how quantum computers work, and what is and is not in scope for quantum computing. In this chapter, we help you develop that understanding so that you can get hands-on and write your own quantum programs in the rest of the book.

1.1 Why does quantum computing matter?

1.2 What is a quantum computer?

1.3 How will we use quantum computers?

1.3.1 What can quantum computers do?

1.3.2 What can’t quantum computers do?

1.4 What is a program?

1.4.1 What is a quantum program?