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1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,

- Aerts, D. (1991). A mechanistic classical laboratory situation violating the Bell inequalities with 2sqrt(2), exactly 'in the same way' as its violations by the EPR experiments.
Helvetica Physica Acta,64,pp. 1-23.

Abstract:We present a macroscopical mechanistic classical laboratory situation, and a classical macroscopical entity, and coincidence measurements on this entity, that lead to a violation of the Bell inequalities corresponding to these coincidence measurements. The violation that we obtain with these coincidence measurements is exactly the same as the violation of the Bell inequalities by the well known coincidence measurements of the quantum entity of two spin 1/2 particles in a singlet spin state. With this we mean that it gives rise to the same numerical values for the expectation values and the same numerical value 2sqrt(2) for the expression used in the Bell inequality. We analyze the origin of the violation, and can formulate the main difference between the violation of Bell inequalities by means of classical entities and the violation of Bell inequalities by means of quantum entities. The making clear of this difference can help us to understand better what the quantum-violation could mean for the nature of reality. We think that some classical concepts will have to be changed, and new concepts will have to be introduced, to be able to understand the reality of the quantum world.- Aerts, D. (1991). A macroscopical classical laboratory situation with only macroscopical classical entities giving rise to a quantum mechanical probability model. In L. Accardi (Ed.),
Quantum Probability and Related Topics, Volume VI(pp. 75-85). Singapore: World Scientific.

Abstract:We propose a macroscopical classical physical entity, giving a detailed description of the preparation apparatuses and the preparations (states) of this entity. We consider experiments that can be performed on the entity, and give a detailed description of the measurement apparatuses, and the measurements used in these experiments. We investigate the collection of probabilities for the outcomes of the measurements the entity being prepared in a given state. Therefore we use the ordinary meaning of probability as approximate relative frequency of repeated experiments, hence experiments consisting of equivalent measurements on equivalently prepared entities. We show that the collection of probabilities that results in this way for our macroscopical entity is the same as the collection of probabilities for the outcomes of the Stern- Gerlach spin measurements on a spin 1/2 quantum entity prepared in a given spin state. By analyzing in which way this purely classical physical situation gives rise to a quantum probability model, we propose an explanation for the non classical probability structure of the quantum probability model. We conclude by showing that this explanation is plausible from a physical point of view, and if accepted makes disappear a lot of the paradoxical nature of the quantum formalism, in the sense that the quantum probabilities do not have to be interpreted any more as 'ontological' or 'intrinsically' present in nature itself.- Aerts, D., Apostel, L., De Moor, B., Hellemans, S., Lesthaege, R., Maex, E., Van Belle, H., Van der Veken, J., Van Geen, R., Van Landschoot, J. (1991).
Wereldbeelden, Van Fragmentering naar Integratie,. Kapellen: Pelckmans.- Aerts, D. and Reignier, J. (1991). The spin of a quantum entity and problems of non-locality. In P. Lahti and P. Mittelstaedt (Eds.),
Symposium on the Foundations of Modern Physics 1990: Quantum Theory of Measurement and Related Philosophical Problems(pp. 9-19). Singapore: World Scientific.

Abstract:We introduce a possible definition for the concept of non-locality in the quantum world, which seems to us a minimal operational definition, taking into account the results of actually performed experiments and reasonings about possible 'gedanken' experiments. The definition is the following: An entity is "non local" if it is possible to prepare it in a state such that it can be influenced from macroscopically separated regions of space by (macroscopically) local apparatus acting only in one (or several) of these separated regions at one time. We discuss two examples of spin superposition experiments which clearly show that quantum entities are non-local. In particular, we show that the familiar Stern- Gerlach experiment allows a nice illustration of this non-locality.- Aerts, D. and Reignier, J. (1991). On the problem of non-locality in quantum mechanics.
Helvetica Physica Acta,64,pp. 527-547.

1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990,

1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,