81 research outputs found
Printable organic and inorganic materials for flexible electrochemical devices
Portuguese Science Foundation - project Electra PTDC/CTM/099124/2008 and the PhD grant SFRH/BD/45224. financial support: Professor E. Fortunato’s ERC 2008 Advanced Grant (INVISIBLE contract number 228144), “APPLE” FP7-NMP-2010-SME/262782-2 and “SMARTEC” FP7-ICT-2009.3.9/25820
From contextuality of a single photon to realism of an electromagnetic wave
Violations of Bell inequalities have been an incontestable indicator of
non-classicality since the seminal paper by John Bell. However, recent claims
of Bell inequalities violations with classical light have cast some doubts on
their significance as hallmarks of non-classicality. Here, we challenge those
claims. The crux of the problem is that such classical experiments simulate
quantum probabilities with intensities of classical fields. However, fields
intensities measurements are radically different from single-photon detections,
which are primitives of any genuine Bell experiment. We show that this
fundamental difference between field intensities measurements and single photon
detections shifts the classical bound of relevant Bell inequalities to its
algebraic limit, leaving no place for their violations.Comment: 11 pages, 4 figure
Single Scale for Odor Intensity in Rat Olfaction
SummaryHumans and laboratory animals are thought to discriminate sensory objects using elemental perceptual features computed by neural circuits in the brain [1, 2]. However, it is often difficult to identify the perceptual features that animals use to make specific comparisons. In olfaction, changes in the concentration of a given odor lead to discriminable changes in both its perceived quality [3, 4] and intensity [5, 6]. Humans use perceived intensity to compare quantities of different odors. Here we establish that laboratory rats also use perceived intensity to compare concentrations of different odors and reveal the perceptual organization of this elemental feature. We first trained rats to classify concentrations of single odors as high or low. When subsequently classifying concentrations of two odors presented on different trials of the same session, rats made errors consistent with using a single intensity criterion for both odors. This allowed us to investigate the relative perceived intensity of different odor pairs. Odor intensity was not only a function of concentration, but varied also with molecular weight and exposure time. These findings demonstrate the role of perceived intensity as an elemental perceptual feature of odors in rat olfaction
Unmodulated spin chains as universal quantum wires
We study a quantum state transfer between two qubits interacting with the
ends of a quantum wire consisting of linearly arranged spins coupled by an
excitation conserving, time-independent Hamiltonian. We show that if we control
the coupling between the source and the destination qubits and the ends of the
wire, the evolution of the system can lead to an almost perfect transfer even
in the case in which all nearest-neighbour couplings between the internal spins
of the wire are equal.Comment: 4 pages, 5 figure
Trapping a particle of a quantum walk on the line
We observe that changing a phase at a single point in a discrete quantum walk
results in a rather surprising localization effect. For certain values of this
phase change the possibility of localization strongly depends on the internal
coin-state of the walker.Comment: 5 pages, 4 figure
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