The task of quantizing general relativity raises serious questions about the meaning of the present formulation and interpretation of quantum mechanics when applied to so fundamental a structure as the space-time geometry itself. This paper seeks to clarify the foundations of quantum mechanics. It presents a reformulation of quantum theory in a form believed suitable for application to general relativity. The aim is not to deny or contradict the conventional formulation of quantum theory, which has demonstrated its usefulness in an overwhelming variety of problems, but rather to supply a new, more general and complete formulation, from which the conventional interpretation can be deduced. The relationship of this new formulation to the older formulation is therefore that of a metatheory to a theory, that is, it is an underlying theory in which the nature and consistency, as well as the realm of applicability, of the older theory can be investigated and clarified.

"relative State" Formulation of Quantum Mechanics

Multiphoton interference reveals strictly nonclassical phenomena. Its applications range from fundamental tests of quantum mechanics to photonic quantum information processing, where a significant fraction of key experiments achieved so far comes from multiphoton state manipulation. The progress, both theoretical and experimental, of this rapidly advancing research is reviewed. The emphasis is given to the creation of photonic entanglement of various forms, tests of the completeness of quantum mechanics (in particular, violations of local realism), quantum information protocols for quantum communication (e.g., quantum teleportation, entanglement purification, and quantum repeater), and quantum computation with linear optics. The scope of the review is limited to ``few-photon'' phenomena involving measurements of discrete observables.

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Multiphoton entanglement and interferometry

Research on hidden variable theories: A review of recent progresses

IF Sir James Jeans finds difficulty in defining philosophy (p. 16), there is no doubt of his qualifications for the task. Emerson, in his essay on Plato as a “representative man”, defines philosophy as the account which the human mind gives to itself of the constitution of the world. It has been given to Jeans to participate effectively in our quest for the “constitution of the world” as physicist, as mathematician, as astronomer, as cosmologist, he has opened windows on Nature-on the origins of planetary, stellar and nebular masses and on the interplay of matter and radiation. Now he attempts what he has earned the right to do : he speaks to us his account of the nature of reality, his views on materialism and what he calls mentalism, on determinism and free-will. Physics and Philosophy By Sir James Jeans. Pp. vii + 222. (Cambridge: At the University Press, 1942.) 8s. 6d. net.

Physics and Philosophy

An american journal of physics

Multisimultaneity is a causal model of relativistic quantum physics which assigns a real time ordering to any set of events, much in the spirit of the pilot-wave picture. Contrary to standard quantum mechanics, it predicts a disappearance of the correlations in a Bell-type experiment when both analyzers are in relative motion such that each one, in its own inertial reference frame, is first to select the output of the photons. We tested this prediction using acousto-optic modulators as moving beam splitters and interferometers separated by 55 m. We did not observe any disappearance of the correlations, in agreement with quantum mechanics.

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Quantum correlations with spacelike separated beam splitters in motion: experimental test of multisimultaneity.

We present an experiment testing quantum correlations with frequency shifted photons. We test Bell inequality with two-photon interferometry where we replace the beam splitters with acousto-optic modulators, which are equivalent to moving beam splitters. We measure the two-photon beats 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.

https://archive-ouverte.unige.ch/unige:36714/ATTACHMENT01

Quantum entanglement with acousto-optic modulators: Two-photon beats and Bell experiments with moving beam splitters

One-particle quantum interference is presented using probably the simplest setup This review of experimental facts may be useful as a short self-contained introduction to quantum mechanics, highlighting the dependence of interference on indistinguishability

Introducing quantum mechanics: One-particle interferences

Single-photon space-like antibunching

We use heralded single photons to perform an antibunching experiment in which the clicks at the detectors are spacelike separated events. The idea of such experiment dates back to the 5th Solvay conference, when it was proposed by Einstein as an expression of his concerns about quantum theory.

Antoine Suarez

Papers

Quantum correlations with spacelike separated beam splitters in motion: experimental test of multisimultaneity.

Quantum entanglement with acousto-optic modulators: Two-photon beats and Bell experiments with moving beam splitters

Introducing quantum mechanics: One-particle interferences

Single-photon space-like antibunching

Single-photon space-like antibunching