Taking the paradox out of the observer's paradox

Richard Webb

А. В. Белинский

It is shown that the violations of Bell’s inequalities observed in optical experiments admit an adequate explanation, on the basis of a model employing four-dimensional joint probabilities, that is consistent with a local hidden-variable theory. For a true experimental demonstration of Bell’s paradox, it is necessary to take account of individual photocounts in the averaging.

Alexander Afriat, F. Selleri

Antonio Puccini

We learn from Quantum Mechanics that the observation of the microscopic world, the measurement (M) of a quantum object, i.e. a particle, inexorably modifies the physical system we wish to examine. What happens is that with the M it takes place a reduction of the state vectors, that is the ‘wave function collapse’ of the measured particle. Why does it happen? No one knows. The enigma of the so-called Measurement Paradox, in our opinion, could be solved if we considered that the light quantum(LQ), as suggested by the Principle of Equivalence Mass-Energy, carries out a dynamic-mass equivalent to its energy. The LQ is indispensable to carry out a M. No M can be carried out without using the quantum of light. Calculus show that a photon of the optic band hits an electron with a momentum bigger than the mass of the electron itself. This may explain why the M induces the implosion of the quantum object observed, together with the collapse of its wave function, giving rise to the Measurement Paradox.

Alexandru Baltag, Sonja Smets

Abstract We take a fresh look at Wigner’s Friend thought-experiment and some of its more recent variants and extensions, such as the Frauchiger-Renner (FR) Paradox. We discuss various solutions proposed in the literature, focusing on a few questions: What is the correct epistemic interpretation of the multiplicity of state assignments in these scenarios? Under which conditions can one include classical observers into the quantum state descriptions, in a way that is still compatible with traditional Quantum Mechanics? Under which conditions can one system be admitted as an additional ‘observer’ from the perspective of another background observer? When can the standard axioms of multi-agent Epistemic Logic (that allow “knowledge transfer” between agents) be applied to quantum-physical observers? In the last part of the paper, we propose a new answer to these questions, sketch a particular formal implementation of this answer, and apply it to obtain a principled solution to Wigner Friend-type paradoxes.

Ralph Hoyt Bacon