5 research outputs found
Reality, measurement and locality in Quantum Field Theory
It is currently believed that the local causality of Quantum Field Theory
(QFT) is destroyed by the measurement process. This belief is also based on the
Einstein-Podolsky-Rosen (EPR) paradox and on the so-called Bell's theorem, that
are thought to prove the existence of a mysterious, instantaneous action
between distant measurements. However, I have shown recently that the EPR
argument is removed, in an interpretation-independent way, by taking into
account the fact that the Standard Model of Particle Physics prevents the
production of entangled states with a definite number of particles. This result
is used here to argue in favor of a statistical interpretation of QFT and to
show that it allows for a full reconciliation with locality and causality.
Within such an interpretation, as Ballentine and Jarret pointed out long ago,
Bell's theorem does not demonstrate any nonlocality.Comment: 15 pages. Published versio
Critical Susceptibility Exponent Measured from Fe/W(110) Bilayers
The critical phase transition in ferromagnetic ultrathin Fe/W(110) films has
been studied using the magnetic ac susceptibility. A statistically objective,
unconstrained fitting of the susceptibility is used to extract values for the
critical exponent (gamma), the critical temperature Tc, the critical amplitude
(chi_o) and the range of temperature that exhibits power-law behaviour. A
fitting algorithm was used to simultaneously minimize the statistical variance
of a power law fit to individual experimental measurements of chi(T). This
avoids systematic errors and generates objective fitting results. An ensemble
of 25 measurements on many different films are analyzed. Those which permit an
extended fitting range in reduced temperature lower than approximately .00475
give an average value gamma=1.76+-0.01. Bilayer films give a weighted average
value of gamma = 1.75+-0.02. These results are in agreement with the
-dimensional Ising exponent gamma= 7/4. Measurements that do not exhibit
power-law scaling as close to Tc (especially films of thickness 1.75ML) show a
value of gamma higher than the Ising value. Several possibilities are
considered to account for this behaviour.Comment: -Submitted to Phys. Rev. B -Revtex4 Format -6 postscript figure
Einstein, incompleteness, and the epistemic view of quantum states
Does the quantum state represent reality or our knowledge of reality? In
making this distinction precise, we are led to a novel classification of hidden
variable models of quantum theory. Indeed, representatives of each class can be
found among existing constructions for two-dimensional Hilbert spaces. Our
approach also provides a fruitful new perspective on arguments for the
nonlocality and incompleteness of quantum theory. Specifically, we show that
for models wherein the quantum state has the status of something real, the
failure of locality can be established through an argument considerably more
straightforward than Bell's theorem. The historical significance of this result
becomes evident when one recognizes that the same reasoning is present in
Einstein's preferred argument for incompleteness, which dates back to 1935.
This fact suggests that Einstein was seeking not just any completion of quantum
theory, but one wherein quantum states are solely representative of our
knowledge. Our hypothesis is supported by an analysis of Einstein's attempts to
clarify his views on quantum theory and the circumstance of his otherwise
puzzling abandonment of an even simpler argument for incompleteness from 1927.Comment: 18 pages, 8 figures, 1 recipe for cupcakes; comments welcom
Implementing Palliative Care Teams Specialized in Dementia in Two Countries: Experiences of Failure and Success
Much is known about palliative care needs of persons with dementia and their family. Less is known about how to successfully implement models that address those needs. We present specialist models in the Netherlands (2017-2018) and Northern Ireland (2016-2017) contrasting its evaluations. From implementation failure in the Netherlands compared with successful implementation in Northern Ireland, we learn that recognizing roles and competencies among all involved is essential in developing effective partnership relationships. All of this is facilitated by referral before the end of life and offering various training programs and in-patient and out-patient services and therapies to show benefits early. </p