2003: Entanglement and Time

Antoine Suarez

quant-ph/0311004

Article about the implications of the experiments with moving measuring devices.

It is argued that recent experiments testing Multisimultaneity prove that quantum entanglement occurs without the flow of time. Bohm's theory cannot be considered a real temporal description.

André Stefanov, Hugo Zbinden, Nicolas Gisin and Antoine Suarez.
Physical Review. A, volume 67, 042115.

Full-length article about the experiment using acoustic waves as moving beam-splitters.
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.

2002: Quantum Correlations With Moving Observers.

N. Gisin, V. Scarani, A. Stefanov, A. Suarez, W. Tittel and H. Zbinden

Optics & Photonics News, December 2002, 51.

Short presentation of the experiments with moving devices.
 

The experiments with moving measuring devices can be considered a fundamental test of quantum mechanics and information. The December issue of Optics and Photonics News highlighted some of the most exciting research to emerge in during 2002. The GAP-Optics experiments studying the quantum correlations with moving observers was a first for a new kind of experiment to test quantum non-locality.

2001: Is there a time ordering behind nonlocal correlations?

Article discussing the results of the experiments with moving beam-splitters.

It is argued that recent experiments with moving beam-splitters demonstrate that there is no real time ordering behind the nonlocal correlations. In Bell's world there is no "before" and "after".

2001: Experimental test of nonlocal quantum correlations in relativistic configurations.

Article describing the before-before experiment using a detector in motion.

We report on an experimental investigation of the tension between quantum nonlocality and relativity. Entangled photons are sent via an optical fiber network to two villages near Geneva, separated by more than 10 km where they are analyzed by interferometers. The photon pair source is set as precisely as possible in the center so that the two photons arrive at the detectors within a time interval of less than 5 ps (corresponding to a path length difference of less than 1 mm). One detector is set in motion so that both detectors, each in its own inertial reference frame, are first to do the measurement! The data always reproduces the quantum correlations, making it thus more difficult to consider the projection postulate as a compact description of real collapses of the wave function.

2000: Quantum mechanics versus multisimultaneity in experiments with acousto-optic choice-devices.

Article proposing "before-before" and "after-after" experiments using acoustic waves as moving beam-splitters.

It is argued that acousto-optic cells act as moving beam-splitters because the velocity corresponding to the Doppler-shift of the reflected photons defines a natural frame in which it is possible to evaluate unambiguously whether the choice between reflection and transmission is before or after. New experimental tests of Multisimultaneity are discussed.

1997: Relativistic nonlocality (or Multisimultaneity) in experiments with moving polarizers and 2 non-before impacts.

Article proposing experiments using the relativistic “after-after” timing.

A recently proposed relativistic nonlocal description (Multisimultaneity) is applied to a so-called “after-after” experiment with 2 non-before impacts, leading to new rules of calculating the joint probabilities, and to predictions conflicting with quantum theory.

1997: Does entanglement depend on the timing of the impacts at the beam-splitters?

First article to propose experiments using measuring devices in motion and the relativistic “before-before” timing.

A new nonlocality experiment with moving beam-splitters is proposed. The experiment is analyzed according to conventional quantum mechanics, and to an alternative nonlocal description (Multisimultaneity) in which superposition depends not only on indistinguishability but also on the timing of the impacts at the beam-splitters.