Theory and experiment in the foundations of quantum theory

Since the epoch-making works of Bell, theory and experiment have worked hand-in-hand to deepen the foundations of quantum theory. Experiment has in many cases confirmed counter-intuitive predictions of the theory, but it also has the power to challenge conventional interpretations of the theory, and, in its study of the Bell inequalities, to come to fundamental conclusions about the nature of the physical universe. These studies have led directly to the exciting new field of quantum information. This paper gives an account of the interaction between theory and experiment in the areas of negative-result and interaction-free measurement, the quantum Zeno effect, and the Einstein–Podolsky–Rosen experiment and the Bell inequalities. A very brief introduction to quantum information theory is also given, stressing its direct connection to theoretical and experimental aspects of quantum theory.