1 - Introduction

Summary

A note to the reader

Quantum optics has grown from a sub-discipline in atomic, molecular, and optical physics to a broad research area that bridges several branches of physics and that captures the imagination of the public. Quantum information science has put quantum optics into the spotlight of modern physics, as has the physics of ultracold quantum gases with its many spectacular connections to condensed-matter physics. Yet through all these exciting developments quantum optics has maintained a characteristic core of ideas that I try to explain in this slim volume.

Quantum optics focuses on the simplest quantum objects, usually light and few-level atoms, where quantum mechanics appears in its purest form without the complications of more complex systems, often demonstrating in the laboratory the thought experiments that the founders of quantum mechanics dreamed of. Quantum optics has been, and will be for the foreseeable future, quintessential quantum mechanics, the quantum mechanics of simple systems, based on a core of simple yet subtle ideas and experiments.

One of the strengths of quantum optics is the close connection between theory and experiment. Although this book necessarily is theoretical, many of the theoretical ideas I describe are guided by experiments or, in turn, have inspired experiments themselves. Another strength of quantum optics is that it is done by individuals or small teams. One single person or a small group can build and perform an entire experiment.