298 research outputs found
On the quantum, classical and total amount of correlations in a quantum state
We give an operational definition of the quantum, classical and total amount
of correlations in a bipartite quantum state. We argue that these quantities
can be defined via the amount of work (noise) that is required to erase
(destroy) the correlations: for the total correlation, we have to erase
completely, for the quantum correlation one has to erase until a separable
state is obtained, and the classical correlation is the maximal correlation
left after erasing the quantum correlations.
In particular, we show that the total amount of correlations is equal to the
quantum mutual information, thus providing it with a direct operational
interpretation for the first time. As a byproduct, we obtain a direct,
operational and elementary proof of strong subadditivity of quantum entropy.Comment: 12 pages ReVTeX4, 2 eps figures. v2 has some arguments clarified and
references update
Electronic and optical properties of beryllium chalcogenides/silicon heterostructures
We have calculated electronic and optical properties of
Si/BeSeTe heterostructures by a semiempirical
tight-binding method. Tight-binding parameters and band bowing of
BeSeTe are considered through a recent model for highly
mismatched semiconductor alloys. The band bowing and the measurements of
conduction band offset lead to a type II heterostucture for
Si/BeSeTe with conduction band minimum in the Si layer and
valence band maximum in the BeSeTe layer. The electronic
structure and optical properties of various (Si/(BeSeTe [001] superlattices have been considered. Two
bands of interface states were found within the bandgap of bulk Si. Our
calculations indicate that the optical edges are below the fundamental bandgap
of bulk Si and the transitions are optically allowed.Comment: 16 pager, 7 figure
Purification of Noisy Entanglement and Faithful Teleportation via Noisy Channels
Two separated observers, by applying local operations to a supply of
not-too-impure entangled states ({\em e.g.} singlets shared through a noisy
channel), can prepare a smaller number of entangled pairs of arbitrarily high
purity ({\em e.g.} near-perfect singlets). These can then be used to faithfully
teleport unknown quantum states from one observer to the other, thereby
achieving faithful transfrom one observer to the other, thereby achieving
faithful transmission of quantum information through a noisy channel. We give
upper and lower bounds on the yield of pure singlets ()
distillable from mixed states , showing if
\bra{\Psi^-}M\ket{\Psi^-}>\half.Comment: 4 pages (revtex) plus 1 figure (postscript). See also
http://vesta.physics.ucla.edu/~smolin/ . Replaced to correct interchanged
and near top of column 2, page
Developing a policy game intervention to enhance collaboration in public health policymaking in three European countries
Background: One of the key elements to enhance the uptake of evidence in public health policies is stimulating cross-sector collaboration. An intervention stimulating collaboration is a policy game. The aim of this study was to describe the design and methods of the development process of the policy game 'In2Action' within a real-life setting of public health policymaking networks in the Netherlands, Denmark and Romania.Methods: The development of the policy game intervention consisted of three phases, pre intervention, designing the game intervention and tailoring the intervention.Results: In2Action was developed as a role-play game of one day, with main focus to develop in collaboration a cross-sector implementation plan based on the approved strategic local public health policy.Conclusions: This study introduced an innovative intervention for public health policymaking. It described the design and development of the generic frame of the In2Action game focusing on enhancing collaboration in local public health policymaking networks. By keeping the game generic, it became suitable for each of the three country cases with only minor changes. The generic frame of the game is expected to be generalizable for other European countries to stimulate interaction and collaboration in the policy process
Enhancement of de Haas-van Alphen Oscillation due to Spin in the Magnetic Breakdown System
The effects of the Zeeman term on the de Haas-van Alphen oscillation is
studied in the magnetic breakdown system. We find that the amplitude of the
oscillation with the frequencies of and are enhanced by the Zeeman term, while they are expected to be
reduced in the semiclassical theory. A possible interpretation of the
experiments in organic conductors is discussed.Comment: 4 pages,4 figures. Submitted to Journal of Physical Society of Japa
Are all noisy quantum states obtained from pure ones?
We ask what type of mixed quantum states can arise when a number of separated
parties start by sharing a pure quantum state and then this pure state becomes
contaminated by noise. We show that not all mixed states arise in this way.
This is even the case if the separated parties actively try to degrade their
initial pure state by arbitrary local actions and classical communication.Comment: 3 pages, no figure
Converse mode piezoelectric coefficient for lead zirconate titanate thin film with interdigitated electrode
The use of interdigitated electrodes (IDEs) in conjunction with ferroelectric thin films shows many attractive features for piezoelectric MEMS applications. In this work, growth of {1 0 0}-textured lead zirconate titanate (PZT) thin films was achieved on insulating MgO buffered, oxidized silicon substrates. IDEs were fabricated by lift-off techniques and cantilevers were formed by dicing. The deflection upon application of a sweeping voltage was measured as large signal response in parallel to the ferroelectric polarization (PV loop). Likewise, the small signal piezoelectric response was measured in parallel to the capacitance-voltage (CV) measurement. In this way, a complete picture of the ferroelectric-piezoelectric element was obtained. From the deflection, the in-plane piezoelectric stress in the PZT thin film was derived and, from this, the effective piezoelectric coefficients. For the latter, two types were defined: an engineering type corresponding to the average value along the IDE, which can directly be compared to coefficient of a parallel plate electrode (PPE) capacitor and a second one that approximately yields the idealized coefficient governing between the electrode fingers. The IDE structures were experimentally compared with PPE structures of identical film thickness. The resulting coefficients were of opposite sign, as expected. In spite of a much better polarization loop, the IDE device showed a lower average piezoelectric stress. The estimated peak value between the fingers was about the same as in the PPE device, corresponding to about 20 C m(-2). Nevertheless, the result is very promising for cases where compressive piezoelectric stresses are required and for preventing cracking due to large piezoelectric tensile stresses in PPE systems
The atmospheric chemistry box model CAABA/MECCA-3.0
We present version 3.0 of the atmospheric chemistry box model CAABA/MECCA. In addition to a complete update of the rate coefficients to the most recent recommendations, a number of new features have been added: chemistry in multiple aerosol size bins; automatic multiple simulations reaching steady-state conditions; Monte-Carlo simulations with randomly varied rate coefficients within their experimental uncertainties; calculations along Lagrangian trajectories; mercury chemistry; more detailed isoprene chemistry; tagging of isotopically labeled species. Further changes have been implemented to make the code more user-friendly and to facilitate the analysis of the model results. Like earlier versions, CAABA/MECCA-3.0 is a community model published under the GNU General Public License
Variational methods
International audienceThis contribution presents derivative-based methods for local sensitivity analysis, called Variational Sensitivity Analysis (VSA). If one defines an output called the response function, its sensitivity to inputs variations around a nominal value can be studied using derivative (gradient) information. The main issue of VSA is then to provide an efficient way of computing gradients. This contribution first presents the theoretical grounds of VSA: framework and problem statement, tangent and adjoint methods. Then it covers pratical means to compute derivatives, from naive to more sophisticated approaches, discussing their various 2 merits. Finally, applications of VSA are reviewed and some examples are presented, covering various applications fields: oceanography, glaciology, meteorology
Evidence for Irradiation Triggered Nonuniform Defect Distribution In Multiharmonic Magnetic Susceptibility of Neutron Irradiated YBa2Cu3O7-x
Multiharmonic ac-magnetic susceptibility \ch11,\chi2,chi3, of neutron
irradiated Li-doped YBa2Cu3O7-x has revealed a nonmonotonic dependence of all
harmonics on the neutron fluence. The irradiation has a strongly depressive
influence on the intergrain connection suggesting an increase of the effective
thickness of the intergranular Josephson junction at aneutron fluence of
0.98x10 cm. Less damaged are the intragrain properties. A
spectacular enhancement of the superconducting intragranular properties
reflected in the characteristics of all harmonics was observed at highest
fluence \Phi = 9.98x10 cm. We assume that this effect results
from the development of a space inhomogeneous distribution with alternating
defectless and defect rich regions.Comment: 24 pages, 9 figures, accepted to J. Supercon
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