23 research outputs found
Photons uncertainty solves Einstein-Podolsky-Rosen paradox
Einstein, Podolsky and Rosen (EPR) pointed out that the quantum-mechanical
description of "physical reality" implied an unphysical, instantaneous action
between distant measurements. To avoid such an action at a distance, EPR
concluded that Quantum Mechanics had to be incomplete. However, its extensions
involving additional "hidden variables", allowing for the recovery of
determinism and locality, have been disproved experimentally (Bell's theorem).
Here, I present an opposite solution of the paradox based on the greater
indeterminism of the modern Quantum Field Theory (QFT) description of Particle
Physics, that prevents the preparation of any state having a definite number of
particles. The resulting uncertainty in photons radiation has interesting
consequences in Quantum Information Theory (e.g. cryptography and
teleportation). Moreover, since it allows for less elements of EPR physical
reality than the old non-relativistic Quantum Mechanics, QFT satisfies the EPR
condition of completeness without the need of hidden variables. The residual
physical reality does never violate locality, thus the unique objective proof
of "quantum nonlocality" is removed in an interpretation-independent way. On
the other hand, the supposed nonlocality of the EPR correlations turns out to
be a problem of the interpretation of the theory. If we do not rely on hidden
variables or new physics beyond QFT, the unique viable interpretation is a
minimal statistical one, that preserves locality and Lorentz symmetry.Comment: Published version, with updated referenc
A physical distinction between a covariant and non covariant reduction process in relativistic quantum theories
Causality imposes strong restrictions on the type of operators that may be
observables in relativistic quantum theories. In fact, causal violations arise
when computing conditional probabilities for certain partial causally connected
measurements using the standard non covariant procedure. Here we introduce
another way of computing conditional probabilities, based on an intrinsic
covariant relational order of the events, which differs from the standard one
when these type of measurements are included. This alternative procedure is
compatible with a wider and very natural class of operators without breaking
causality. If some of these measurements could be implemented in practice as
predicted by our formalism, the non covariant, conventional approach should be
abandoned. Furthermore, the description we promote here would imply a new
physical effect where interference terms are suppressed as a consequence of the
covariant order in the measurement process.Comment: 7 pages, latex file, 1 ps figure. Major presentation changes. To
appear in New Journal of Physic