84 research outputs found
Schrödinger, Szilard, and the emergence of the EPR argument
Einstein, Podolsky and Rosenâs âCan quantum mechanical description of reality be considered complete?â(1935) and Schrödingerâs âDie gegenwĂ€rtige Situation in der Quantenmechanikâ (1936) are commonly accepted as the seminal papers for the modern study of quantum mechanical entanglement. However, not much has been known about the prehistory of these papers. We were able to trace the development of both Einsteinâs and Schrödingerâs thought, using Schrödingerâs correspondence and especially his extensive research notes. We especially found that they both got important input from Leo Szilard, who proposed in 1931 a thought experiment that is a direct precursor to the EPR experiment and a quantum mechanical state that is essentially identical to the EPR state
Current and emerging developments in subseasonal to decadal prediction
Weather and climate variations of subseasonal to decadal timescales can have enormous social, economic and environmental impacts, making skillful predictions on these timescales a valuable tool for decision makers. As such, there is a growing interest in the scientific, operational and applications communities in developing forecasts to improve our foreknowledge of extreme events. On subseasonal to seasonal (S2S) timescales, these include high-impact meteorological events such as tropical cyclones, extratropical storms, floods, droughts, and heat and cold waves. On seasonal to decadal (S2D) timescales, while the focus remains broadly similar (e.g., on precipitation, surface and upper ocean temperatures and their effects on the probabilities of high-impact meteorological events), understanding the roles of internal and externally-forced variability such as anthropogenic warming in forecasts also becomes important.
The S2S and S2D communities share common scientific and technical challenges. These include forecast initialization and ensemble generation; initialization shock and drift; understanding the onset of model systematic errors; bias correct, calibration and forecast quality assessment; model resolution; atmosphere-ocean coupling; sources and expectations for predictability; and linking research, operational forecasting, and end user needs. In September 2018 a coordinated pair of international conferences, framed by the above challenges, was organized jointly by the World Climate Research Programme (WCRP) and the World Weather Research Prograame (WWRP). These conferences surveyed the state of S2S and S2D prediction, ongoing research, and future needs, providing an ideal basis for synthesizing current and emerging developments in these areas that promise to enhance future operational services. This article provides such a synthesis
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Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks
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çźââADARïŒAdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...ćŠäœïŒć·„ćŠçĄćŁ«éąçł»äžäžïŒäżĄæŻç§ćŠäžææŻćŠéąé俥淄çšçł»_é俥äžäżĄæŻçł»ç»ćŠć·ïŒ2332007115216
Quantum Mechanics and Reality: An Interpretation of Everett's Theory.
The central part of Everett's formulation of quantum mechanics is a quantum mechanical model of memory and of observation as the recording of information in a memory. To use this model as an answer to the measurement problem, Everett has to assume that a conscious observer can be in a superposition of such memory states and be unaware of it. This assumption has puzzled generations of readers. The fundamental aim of this dissertation is to find a set of simpler assumptions which are sufficient to show that Everett's model is empirically adequate. I argue that Everett's model needs three assumptions to account for the process of observation: an assumption of decoherence of observers as quantum mechanical systems; an assumption of supervenience of mental states (qualities) over quantum mechanical properties; and an assumption about the interpretation of quantum mechanical states in general: quantum mechanical states describe ensembles of states of affairs coexisting in the same system. I argue that the only plausible understanding of such ensembles is as ensembles of possibilities, and that all standard no-collapse interpretations agree in this reading of quantum mechanical states. Their differences can be understood as different theories about what marks the real state within this ensemble, and Everett's theory as the claim that no additional 'mark of reality' is necessary. Using the three assumptions, I argue that introspection cannot determine the objective quantum mechanical state of an observer. Rather, the introspective qualities of a quantum mechanical state can be represented by a (classical) statistical ensemble of subjective states. An analysis of these subjective states and their dynamics leads to the conclusion that they suffice to give empirically correct predictions. The argument for the empirical adequacy of the subjective state entails that knowledge of the objective quantum mechanical state is impossible in principle. Empirical reality for a conscious observer is not described by the objective state, but by a Everettian relative state conditional on the subjective state, and no theoretical 'mark of reality' is necessary for this concept of reality. I compare the resulting concept of reality to Kant's distinction between empirical and transcendental reality
DNVF Memorandum Health Services Research in Oncology
Health services research in oncology deals with all situations which cancer patients face. It looks at the different phases of care, i. e. prevention / early detection, prehabilitation, diagnostics, therapy, rehabilitation and palliative care as well as the various actors, including those affected, the carers and self-help. It deals with healthy people (e. g. in the context of prevention / early detection), patients and cancer survivors. Due to the nature of cancer and the existing care structures, there are a number of specific contents for health services research in oncology compared to general health services research while the methods remain essentially identical. This memorandum describes the subject, illustrates the care structures and identifies areas of health services research in oncology. This memorandum has been prepared by the Oncology Section of the German Network for Health Services Research and is the result of intensive discussions
Production of charged pions, kaons, and (anti-)protons in Pb-Pb and inelastic collisions at = 5.02 TeV
International audienceMid-rapidity production of , and ()p measured by the ALICE experiment at the LHC, in Pb-Pb and inelastic pp collisions at = 5.02 TeV, is presented. The invariant yields are measured over a wide transverse momentum () range from hundreds of MeV/ up to 20 GeV/. The results in Pb-Pb collisions are presented as a function of the collision centrality, in the range 090%. The comparison of the -integrated particle ratios, i.e. proton-to-pion (p/) and kaon-to-pion (K/) ratios, with similar measurements in Pb-Pb collisions at = 2.76 TeV show no significant energy dependence. Blast-wave fits of the spectra indicate that in the most central collisions radial flow is slightly larger at 5.02 TeV with respect to 2.76 TeV. Particle ratios (p/, K/) as a function of show pronounced maxima at 3 GeV/ in central Pb-Pb collisions. At high , particle ratios at 5.02 TeV are similar to those measured in pp collisions at the same energy and in Pb-Pb collisions at = 2.76 TeV. Using the pp reference spectra measured at the same collision energy of 5.02 TeV, the nuclear modification factors for the different particle species are derived. Within uncertainties, the nuclear modification factor is particle species independent for high and compatible with measurements at = 2.76 TeV. The results are compared to state-of-the-art model calculations, which are found to describe the observed trends satisfactorily
Measurement of Î(1520) production in pp collisions at âs = 7 TeV and pâPb collisions at âsNN = 5.02 TeV
The production of the Î(1520) baryonic resonance has been measured at midrapidity in inelastic pp collisions at sâ = 7 TeV and in p-Pb collisions at sNNââââ = 5.02 TeV for non-single diffractive events and in multiplicity classes. The resonance is reconstructed through its hadronic decay channel Î(1520) â pKâ and the charge conjugate with the ALICE detector. The integrated yields and mean transverse momenta are calculated from the measured transverse momentum distributions in pp and p-Pb collisions. The mean transverse momenta follow mass ordering as previously observed for other hyperons in the same collision systems. A Blast-Wave function constrained by other light hadrons (Ï, K, K0S, p, Î) describes the shape of the Î(1520) transverse momentum distribution up to 3.5 GeV/c in p-Pb collisions. In the framework of this model, this observation suggests that the Î(1520) resonance participates in the same collective radial flow as other light hadrons. The ratio of the yield of Î(1520) to the yield of the ground state particle Î remains constant as a function of charged-particle multiplicity, suggesting that there is no net effect of the hadronic phase in p-Pb collisions on the Î(1520) yield
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