Dissidents and the Second Quantum Revolution

Abstract

The second quantum revolution, which may lead to a major technological breakthrough in science and technology with the creation of quantum computers, was the term coined by the French physicist Alain Aspect to describe changes in physics, the beginnings of which date back to the 1960s. To flesh out the new term he brought together two different threads. The first one embraced the emergence of the awareness of the importance of a new physical effect, entanglement. This refers to the quantum description of a composite system which is not reducible to the sum of its parts. It started a conceptual revolution, including the perspective of building quantum computers with calculation power exponentially greater than the best computers of today. The second thread derives from physicists’ ability to isolate, control, and observe single quantum systems such as electrons, photons, neutrons and atoms. Finally these threads merged into the creation of a new field of research entitled quantum information. In Aspect’s formulation, found in his introduction to John Bell’s papers (Speakable and unspeakable in quantum mechanics: collected papers on quantum philosophy. Cambridge University Press, 2004), he posited two quantum revolutions taking place in the twentieth century. The first one, in the first half of the century, created the scientific theory that describes the behavior of atoms, radiation, and their interactions. The second one occurred in the second half and is still evolving, as the promise of quantum computers remains unaccomplished. This book deals with the origins of this alleged second revolution—from the early 1950s to the mid-1990s—and is a historical account of the context and intellectual aspects that arose from the renewal of research on the foundations of quantum physics. It roughly covers the period from the 1950s, when this research gained momentum with the appearance of new interpretations for the mathematical formalism of this physical theory, to the early 1990s, when research on these foundations was established as a promising topic on the agenda of research in physics. As “quantum information” became a new field of research in the middle of the 1990s, this narrative ends when quantum information as a blossoming field of research starts. This book can thus be regarded as a prehistory of quantum information.