Papers by Willem M. de Muynck
Quantum nonlocality without counterfactual definiteness?
Foundations of Physics Letters, 1990
ABSTRACT Stapp's recent proof of the nonlocality of quantum mechanics is critically discu... more ABSTRACT Stapp's recent proof of the nonlocality of quantum mechanics is critically discussed. It is demonstrated that in his derivation of the Bell inequalities an extra requirement, over locality, is used, which is tantamount to counterfactual definiteness, and that is not a consequence of locality.
On the Feasibility and Usefulness of Applying the Schrödinger Equation to Quantum Measurement
Applications of generalized quantum mechanics
A derivation of local commutativity from macrocausality using a quantum mechanical theory of measurement
Foundations of Physics, 1984

Optical Experiments Illustrating the Significance of the Bell Inequalities
Coherence and Quantum Optics VI, 1989
Recently the possibility of generating squeezed states of light has provided for an important new... more Recently the possibility of generating squeezed states of light has provided for an important new tool in studying questions that are of crucial importance for the foundations of quantum mechanics. Squeezed states, being states of the electromagnetic field without a classical analogue, seem particularly suited for studying effects that are typically quantum mechanical. For this reason it is not surprising that they have been applied in tests of the Heisenberg uncertainty relation1 and of the Bell inequalities (BI)2In the latter experiment, which was performed by Ou and Mandel2, the two-photon character of squeezed states generated in parametric downconversion is used in order to obtain a correlated state of the electromagnetic field violating the BI. This was verified in Einstein-Podolsky-Rosen (EPR)-like experiments in which the joint probability P(0 1,0 2) was measured of one photon being polarized in the direction and the other one in the direction0 2In order to test the BI the experiment was repeated for different values of 0t and 02, yielding -1 < P(01, 02) - P(01, 02) +(01, 02)+ (01, 02) – P(O1)-P(0 2 ) ≤ 0 if the BI are satisfied.
arXiv: Quantum Physics, 2007
In the past both instrumentalism and empiricism have inspired certain pragmatic elements into the... more In the past both instrumentalism and empiricism have inspired certain pragmatic elements into the Copenhagen interpretation of quantum mechanics. The relation of such pragmatisms with the correspondence principle is discussed. It is argued that neither Bohr nor Heisenberg did take ‘correspondence’ in one of these forms, and that it, in particular, was Bohr’s classical attitude which caused him to apply in an inconsistent way his correspondence principle to the Einstein-Podolsky-Rosen experiment, thus causing much confusion. It is demonstrated that an empiricist pragmatism is conducive to an explanation of violation of the Bell inequalities as a consequence of ‘complementarity’ in the sense of ‘mutual disturbance in a joint nonideal measurement of incompatible observables’ rather than as being caused by ‘nonlocal influences’.
Journal of Physics A: Mathematical and General, 1993
Abstmd. "he measurement of spin: observables using a Stern-Gerlach type device is studied. A magn... more Abstmd. "he measurement of spin: observables using a Stern-Gerlach type device is studied. A magnetic field with a dominant dipole component Leads to a measurement of spin in one direction. The measurement is shown to be feasible (in principle) for electrons as well as for neutral particles. A quadrupole field leads to a joint measurement of two incompatible spin observables. Again, both the electron and the neutral case are presented. The accuracy of the joint measurement is compared to the limit imposed by the uncertainty principle.
The Einstein-Podolsky-Rosen problem
Foundations of Quantum Mechanics, an Empiricist Approach, 2004
Foundations of Physics Letters, 1992
A quantum-mechanical theory of joint nonideal measurement of incompatible polarization observable... more A quantum-mechanical theory of joint nonideal measurement of incompatible polarization observables is applied to axt EPtLlike experiment. It is demonstrated that this experiment yields both information satisfying and information violating the Bell inequalities. The measurement is also discussed in the context of a local hidden-variables theory. It is argued that the violation of an additional assumption of reproducibility of the hidden variable rather than violation of locality may be responsible for the violation of the Bell inequalities.
AIP Conference Proceedings, 2009
Notwithstanding it is well known that von Neumann's projection postulate is inapplicable to most ... more Notwithstanding it is well known that von Neumann's projection postulate is inapplicable to most realistic measurement procedures, it keeps haunting the foundations of quantum mechanics. In particular its applicability to EPR experiments is often assumed. In the present contribution this problem is considered from the point of view of a quantum mechanical theory of measurement, allowing a treatment of projection in EPR experiments as a special case of conditional preparation. The conditions are spelled out under which the postulate may be applicable.
Interpretations of quantum mechanics, and interpretations of violations of Bell’s inequality
Subquantum or hidden-variables theories
Foundations of Quantum Mechanics, an Empiricist Approach
Wigner distributions and the joint measurement of incompatible observables
Arxiv preprint quant-ph/9606007, 1996
On an alternative interpretation of the bell inequalities
Physics Letters A, 1984
Haroche-Ramsey experiment as a generalized measurement
Physical Review A, 2001
The Copenhagen interpretation, and pragmatism
Arxiv preprint arXiv:0705.2144, 2007
Simultaneous measurement and joint probability distributions in quantum mechanics
Foundations of Physics, 1979
Von Neumann-L�ders Projection, and its Applicability to EPR Experiments
Nonideal quantum measurements
Foundations of Physics, Jan 2, 1990
From Copenhagen to Neo-Copenhagen Interpretation
AIP Conference Proceedings, 2007
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Papers by Willem M. de Muynck