Quantum physics has, on the one hand, drastically changed our theoretical description of the physical world and has, on the other hand, revolutionized everyday life, by allowing us to build lasers, atomic clocks used in GPS, and semiconductor-based devices such as laptop computers and smartphones. The object of this book is to give a self-contained introduction to both aspects. It contains a detailed account of the foundational principles: superposition, entanglement, quantum non-locality, decoherence and measurement theory, and of some selected applications: quantum cryptography and quantum computers, cold atoms, light emitting and laser diodes, and atomic clocks. The book is aimed at a general audience and the only prerequisite is a high-school background in mathematics.
