The manner in which states of some quantum systems become effectively classical is of
great significance for the foundations of quantum physics, as well as for problems of …

We review the main works in the field of nonlinear interferometers, which has been
developing ever since the start of nonlinear optics and has seen growing interest in recent …

Meeting the Universe Halfway is an ambitious book with far-reaching implications for
numerous fields in the natural sciences, social sciences, and humanities. In this volume …

The counter-intuitive aspects of quantum physics have been for long illustrated by thought
experiments, from Einstein's photon box to Schrödinger's cat. These experiments have now …

Over the course of the past decade, decoherence has become a ubiquitous scienti? c term
popular in all kinds of research, from fundamental theories of quantum physics to …

We experimentally entangle freely propagating particles that never physically interacted with
one another or which have never been dynamically coupled by any other means. This …

Entangled photon pairs are a critical resource in quantum communication protocols ranging
from quantum key distribution to teleportation. The current workhorse technique for …

We propose an interferometric method for measuring the orbital angular momentum of
single photons. We demonstrate its viability by sorting four different orbital angular …

Introduction More than a century ago, Durkheim (1893, p. 64), to whom we owe the concept
of social cohesion or social solidarity, stated that it is “completely a moral phenomenon …

Using the process of spontaneous parametric down-conversion in a two-crystal geometry,
we have generated a source of polarization-entangled photon pairs that is more than ten …