9,128 research outputs found
Controlling the composition of a confined fluid by an electric field
Starting from a generic model of a pore/bulk mixture equilibrium, we propose
a novel method for modulating the composition of the confined fluid without
having to modify the bulk state. To achieve this, two basic mechanisms -
sensitivity of the pore filling to the bulk thermodynamic state and electric
field effect - are combined. We show by Monte Carlo simulation that the
composition can be controlled both in a continuous and in a jumpwise way. Near
the bulk demixing instability, we demonstrate a field induced population
inversion in the pore. The conditions for the realization of this method should
be best met with colloids, but being based on robust and generic mechanisms, it
should also be applicable to some molecular fluids.Comment: 9 pages, 5 figure
A phenomenological theory giving the full statistics of the position of fluctuating pulled fronts
We propose a phenomenological description for the effect of a weak noise on
the position of a front described by the Fisher-Kolmogorov-Petrovsky-Piscounov
equation or any other travelling wave equation in the same class. Our scenario
is based on four hypotheses on the relevant mechanism for the diffusion of the
front. Our parameter-free analytical predictions for the velocity of the front,
its diffusion constant and higher cumulants of its position agree with
numerical simulations.Comment: 10 pages, 3 figure
An Intrisic Topology for Orthomodular Lattices
We present a general way to define a topology on orthomodular lattices. We
show that in the case of a Hilbert lattice, this topology is equivalent to that
induced by the metrics of the corresponding Hilbert space. Moreover, we show
that in the case of a boolean algebra, the obtained topology is the discrete
one. Thus, our construction provides a general tool for studying orthomodular
lattices but also a way to distinguish classical and quantum logics.Comment: Under submission to the International Journal of Theoretical Physic
Data sources for rescuing the rich heritage of Mediterranean historical surface climate data
10.1002/gdj3.4Availability of long-term and high-quality instrumental climate records is still insufficient and the rich heritage of meteorological surface observations is largely underexploited in many parts of the world. This is particularly striking over the Greater Mediterranean region (GMR), where meteorological observations have been taken since the 18th century at some locations. The lack of high quality and long series here is despite this region being regarded as a climate change hot spot. This article mainly assesses relevant sources containing Mediterranean historical climate data and metadata either from online repositories worldwide or physical archives, with the emphasis here on the rich holdings kept at French archives. A particular case study is the data rescue (DARE) program undertaken by the Algerian National Meteorological Service, as well as some of the past and ongoing projects and initiatives aimed at enhancing climate data availability and accessibility over the GMR. Our findings point to the high potential for undertaking DARE activities over the GMR and the need for bringing longer and higher quality climate time series to support a diverse number of scientific and technical assessments and policies
High energy scattering in QCD as a statistical process
The scattering of two hadronic objects at high energy is similar to a
reaction-diffusion process described by the stochastic Fisher-Kolmogorov
equation. This basic observation enables us to derive universal properties of
the scattering amplitudes in a straightforward way, by borrowing some general
results from statistical physics.Comment: 4 pages, 2 figures; talk presented at Baryons 2004, Palaiseau,
France, October 200
Reweighting of the form factors in exclusive B --> X ell nu decays
A form factor reweighting technique has been elaborated to permit relatively
easy comparisons between different form factor models applied to exclusive B
--> X l nu decays. The software tool developped for this purpose is described.
It can be used with any event generator, three of which were used in this work:
ISGW2, PHSP and FLATQ2, a new powerful generator. The software tool allows an
easy and reliable implementation of any form factor model. The tool has been
fully validated with the ISGW2 form factor hypothesis. The results of our
present studies indicate that the combined use of the FLATQ2 generator and the
form factor reweighting tool should play a very important role in future
exclusive |Vub| measurements, with largely reduced errors.Comment: accepted for publication by EPJ
Universal behavior of QCD amplitudes at high energy from general tools of statistical physics
We show that high energy scattering is a statistical process essentially
similar to reaction-diffusion in a system made of a finite number of particles.
The Balitsky-JIMWLK equations correspond to the time evolution law for the
particle density. The squared strong coupling constant plays the role of the
minimum particle density. Discreteness is related to the finite number of
partons one may observe in a given event and has a sizeable effect on physical
observables. Using general tools developed recently in statistical physics, we
derive the universal terms in the rapidity dependence of the saturation scale
and the scaling form of the amplitude, which come as the leading terms in a
large rapidity and small coupling expansion.Comment: 14 pages, 2 figures; v2: Secs. 2 and 3 substantially rewritten and
Sec. 4 expanded in order to make more explicit the connection with
statistical physics. Acknowledgment and reference added. Results and
conclusions unchanged. To appear in Phys. Lett.
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