Experimental realization of Popperʼs experiment

Yoon-Ho Kim, Yanhua H. Shih

Giacomo Pantaleoni

The focus of this work is discussing the realization of space based experiments testing quantum mechanics, specifically quantum optics. The main experimental work is the practical realization of the earthbound part of a possible interferometric experiment that can be realized with a delayed-choice operational mode. The full Earth-satellite realization of this experimental scheme could set a new record on the distance to which delayed-choice schemes have been experimentally realized. General relativistic effects on Earth-satellite experiments is also discussed, in the case of two different setups. One of those is essentially the ground-space implementation of the interferometer realized in the laboratory, while the other represents a different possibility that could in principle measure gravitational redshift to single photons to greater extent. Which-path behavior and interference were observed to a very good degree on the interferometer realized in the lab. Specifically, the assessment of interference visibility, which was done after careful alignement of the setup, yields a value of approximately 95%, and a comparable value of approx 93% was obtained with an alternative setup which was also experimentally realized in the laboratory. As far as theoretical computations are concerned, a good formalism to deal with space-based interferometric measurements was pointed out, which allows to take into account both special relativistic contributes and general relativistic corrections to the amplitude describing the photons involved with this kind of experiments. Two different setups, which are candidates for the measurement of single photon gravitational redshift, were analyzed with this formalism. The setup with one interferometer on the ground and the other on the satellite, in principle, constitutes a good way to observe this effect by means of a phase measurement, to the first order in the gravitational potentials.

Pedro Sancho

Yanhua H. Shih

J. E. F. Araújo, João L. Cordovil, Croca +1 more

Abstract: Recently the experimental group of A. Aspect published a very interesting experimental realization of the well known Wheeler’s delayed-choice Gedanken Experiment. In the paper the authors refer to the usual, non causal linear explanation of the experiment. In the present work we show how it is possible, and furthermore desirable, to explain the same experiment in terms of the modern local causal and nonlinear quantum theory, inspired in the work of the great physicist Louis de Broglie. In this way we are able to get rid of the mysteries and of the weird features of the orthodox interpretation, like retractions in time, and therefore recover causality and rationality once more.

Hikida, Satoshi

Violations of Bell inequalities show that quantum entanglement produces nonclassical correlations between spatially separated systems. In quantum eraser experiments, interference is restored once distinguishability is removed. This highlights the essential role of distinguishability in quantum state transformations. However, it has not been recognized that a paradox can emerge using only conventional optical transformations of quantum states, and no experiment has been proposed to determine which of three mutually exclusive hypotheses outside the implicit assumptions of standard optical transformations and capable of resolving the paradox is realized in practice. Here we show that a paradox emerges in a configuration that reduces the distinguishability of an entangled state, and we propose an experiment capable of identifying which hypothesis is realized. Theory alone cannot determine which hypothesis is realized. Therefore, experimental verification is required. Regardless of the experimental outcome, the experiment would reveal an unrecognized property linking entanglement and distinguishability.