85 research outputs found
Bell nonlocality, signal locality and unpredictability (or What Bohr could have told Einstein at Solvay had he known about Bell experiments)
The 1964 theorem of John Bell shows that no model that reproduces the
predictions of quantum mechanics can simultaneously satisfy the assumptions of
locality and determinism. On the other hand, the assumptions of \emph{signal
locality} plus \emph{predictability} are also sufficient to derive Bell
inequalities. This simple theorem, previously noted but published only
relatively recently by Masanes, Acin and Gisin, has fundamental implications
not entirely appreciated. Firstly, nothing can be concluded about the
ontological assumptions of locality or determinism independently of each other
-- it is possible to reproduce quantum mechanics with deterministic models that
violate locality as well as indeterministic models that satisfy locality. On
the other hand, the operational assumption of signal locality is an empirically
testable (and well-tested) consequence of relativity. Thus Bell inequality
violations imply that we can trust that some events are fundamentally
\emph{unpredictable}, even if we cannot trust that they are indeterministic.
This result grounds the quantum-mechanical prohibition of arbitrarily accurate
predictions on the assumption of no superluminal signalling, regardless of any
postulates of quantum mechanics. It also sheds a new light on an early stage of
the historical debate between Einstein and Bohr.Comment: Substantially modified version; added HMW as co-autho
Emerging Role for the PERK/eIF2α/ATF4 in Human Cutaneous Leishmaniasis.
Leishmania parasites utilize adaptive evasion mechanisms in infected macrophages to overcome host defenses and proliferate. We report here that the PERK/eIF2α/ATF4 signaling branch of the integrated endoplasmic reticulum stress response (IERSR) is activated by Leishmania and this pathway is important for Leishmania amazonensis infection. Knocking down PERK or ATF4 expression or inhibiting PERK kinase activity diminished L. amazonensis infection. Knocking down ATF4 decreased NRF2 expression and its nuclear translocation, reduced HO-1 expression and increased nitric oxide production. Meanwhile, the increased expression of ATF4 and HO-1 mRNAs were observed in lesions derived from patients infected with the prevalent related species L.(V.) braziliensis. Our data demonstrates that Leishmania parasites activate the PERK/eIF2α/ATF-4 pathway in cultured macrophages and infected human tissue and that this pathway is important for parasite survival and progression of the infection
Study of elementary reactions with the hades dielectron spectrometer
Results obtained with the HADES dielectron spectrometer at GSI are discussed, with emphasis on dilepton production in elementary reactions.Díaz Medina, José, [email protected] ; Gil Ortiz, Alejandro, [email protected]
Character of superposed states under deterministic LOCC
In this paper we investigate the effect of superposition of states on local
conversion of pure bipartite states under deterministic LOCC. We are able to
form a bridge between comparable and incomparable classes of states through the
linear superposition of states. For example, if we consider two pairs of
incomparable states, then their superposition may result into a comparable pair
of states. We investigate many such cases and provide some of the results in
tabular form. We also investigate the entanglement behavior of such classes of
states, specifically their monotone nature. Finally we provide some bounds of
different measures of entanglement based on the idea of comparability and
incomparability under deterministic LOCC.Comment: 9 pages, pdflatex, no figure, to appear in the journal Quantum
Information Processin
Study of dielectron production in C+C collisions at 1 AGeV
The emission of e+e- pairs from C+C collisions at an incident energy of 1 GeV
per nucleon has been investigated. The measured production probabilities,
spanning from the pi0-Dalitz to the rho/omega! invariant-mass region, display a
strong excess above the cocktail of standard hadronic sources. The
bombarding-energy dependence of this excess is found to scale like pion
production, rather than like eta production. The data are in good agreement
with results obtained in the former DLS experiment.Comment: submitted to Physics Letters
Thermal Casimir effect in ideal metal rectangular boxes
The thermal Casimir effect in ideal metal rectangular boxes is considered
using the method of zeta functional regularization. The renormalization
procedure is suggested which provides the finite expression for the Casimir
free energy in any restricted quantization volume. This expression satisfies
the classical limit at high temperature and leads to zero thermal Casimir force
for systems with infinite characteristic dimensions. In the case of two
parallel ideal metal planes the results, as derived previously using thermal
quantum field theory in Matsubara formulation and other methods, are reproduced
starting from the obtained expression. It is shown that for rectangular boxes
the temperature-dependent contribution to the electromagnetic Casimir force can
be both positive and negative depending on side lengths. The numerical
computations of the scalar and electromagnetic Casimir free energy and force
are performed for cubesComment: 10 pages, 4 figures, to appear in Europ. Phys. J.
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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