A Mach-Zehnder Interferometer for a Two-Photon Wave Packet

We propose an experiment that permits observation of the de Broglie two-photon wave packet behavior for a pair of photons, using a Mach-Zehnder interferometer. It is based on the use of pulsed lasers to generate pairs of photons via spontaneous parametric down-conversion and the post-selection of events. It differs from previous realizations by the use of a third time-correlated photon to engineer the state of the photons. The same technique can give us which-path information via an ``interaction-free'' experiment and can be used in other experiments on the foundations of quantum mechanics related to wave-particle duality and to nonlocality.Comment: Submmited for publication in Physical Review

Are There Quantum Effects Coming from Outside Space-time? Nonlocality, free will and "no many-worlds"

Observing the violation of Bell's inequality tells us something about all possible future theories: they must all predict nonlocal correlations. Hence Nature is nonlocal. After an elementary introduction to nonlocality and a brief review of some recent experiments, I argue that Nature's nonlocality together with the existence of free will is incompatible with the many-worlds view of quantum physics.Comment: Talk presented at the meeting "Is Science Compatible with Our Desire for Freedom?" organised by the Social Trends Institute at the IESE Business School in Barcelona, Octobre 201

Quantum entanglement with acousto-optic modulators: 2-photon beatings and Bell experiments with moving beamsplitters

We present an experiment testing quantum correlations with frequency shifted photons. We test Bell inequality with 2-photon interferometry where we replace the beamsplitters by acousto-optic modulators, which are equivalent to moving beamsplitters. We measure the 2-photon beatings induced by the frequency shifts, and we propose a cryptographic scheme in relation. Finally, setting the experiment in a relativistic configuration, we demonstrate that the quantum correlations are not only independent of the distance but also of the time ordering between the two single-photon measurements.Comment: 14 pages, 16 figure

About entanglement properties of kaons and tests of hidden variables models

In this letter we discuss entanglement properties of neutral kaons systems and their use for testing local realism. In particular we show that, as previous proposals, also a scheme recently suggested for performing a test of hidden variable theories against standard quantum mechanics cannot be conclusive

The JWST early-release science program for direct observations of exoplanetary systems II: A 1 to 20 μm spectrum of the planetary-mass companion VHS 1256-1257 b

Stars and planetary system