1,071 research outputs found
Universality classes of the Kardar-Parisi-Zhang equation
We re-examine mode-coupling theory for the Kardar-Parisi-Zhang (KPZ) equation
in the strong coupling limit and show that there exists two branches of
solutions. One branch (or universality class) only exists for dimensionalities
and is similar to that found by a variety of analytic approaches,
including replica symmetry breaking and Flory-Imry-Ma arguments. The second
branch exists up to and gives values for the dynamical exponent
similar to those of numerical studies for .Comment: 4 pages, 1 figure, published versio
Non-perturbative Approach to Critical Dynamics
This paper is devoted to a non-perturbative renormalization group (NPRG)
analysis of Model A, which stands as a paradigm for the study of critical
dynamics. The NPRG formalism has appeared as a valuable theoretical tool to
investigate non-equilibrium critical phenomena, yet the simplest -- and
nontrivial -- models for critical dynamics have never been studied using NPRG
techniques. In this paper we focus on Model A taking this opportunity to
provide a pedagological introduction to NPRG methods for dynamical problems in
statistical physics. The dynamical exponent is computed in and
and is found in close agreement with results from other methods.Comment: 13 page
AGR'EAU: a farmer centered grassroots effort to develop a resource-efficient, eco-friendly, climate-smart agriculture across tle Adour-Garonne catchment basin (south west of France)
info:eu-repo/semantics/publishedVersio
General framework of the non-perturbative renormalization group for non-equilibrium steady states
This paper is devoted to presenting in detail the non-perturbative
renormalization group (NPRG) formalism to investigate out-of-equilibrium
systems and critical dynamics in statistical physics. The general NPRG
framework for studying non-equilibrium steady states in stochastic models is
expounded and fundamental technicalities are stressed, mainly regarding the
role of causality and of Ito's discretization. We analyze the consequences of
Ito's prescription in the NPRG framework and eventually provide an adequate
regularization to encode them automatically. Besides, we show how to build a
supersymmetric NPRG formalism with emphasis on time-reversal symmetric
problems, whose supersymmetric structure allows for a particularly simple
implementation of NPRG in which causality issues are transparent. We illustrate
the two approaches on the example of Model A within the derivative expansion
approximation at order two, and check that they yield identical results.Comment: 28 pages, 1 figure, minor corrections prior to publicatio
Mid-term report for the CORE Organic II funded project. “Innovative cropping Practices to increase soil health of organic fruit tree orchards” BIO-INCROP
Activities performed in the first part of BIO-INCROP project concern five of the eight main objectives fixed in the project proposal. They are:
Evaluation of soil borne pest and pathogens involved in replant disease
Role of rhizospheric bacterial and fungal communities in plant health
Selection of naturally available resources to increase microbial diversity and biomass
Compost and organic amendments
Evaluation of biologically active formulates
The document reports main research results and shows main items of dissemination activity performed in the first part of the project
Non-Perturbative Renormalization Group for Simple Fluids
We present a new non perturbative renormalization group for classical simple
fluids. The theory is built in the Grand Canonical ensemble and in the
framework of two equivalent scalar field theories as well. The exact mapping
between the three renormalization flows is established rigorously. In the Grand
Canonical ensemble the theory may be seen as an extension of the Hierarchical
Reference Theory (L. Reatto and A. Parola, \textit{Adv. Phys.}, \textbf{44},
211 (1995)) but however does not suffer from its shortcomings at subcritical
temperatures. In the framework of a new canonical field theory of liquid state
developed in that aim our construction identifies with the effective average
action approach developed recently (J. Berges, N. Tetradis, and C. Wetterich,
\textit{Phys. Rep.}, \textbf{363} (2002))
Limit analysis of reinforced masonry vaults
Reinforced brick masonry has experienced only scarce use as a fully structural material due to, among other reasons, the lack of design criteria and calculation tools allowing a scientific, but also practical, engineering approach to design and assessment. Aiming at contributing to a more widespread use of this material, a simplified method for the ultimate analysis of reinforced masonry arches and cylindrical vaults, based on the lower-bound theorem (or static approach) of plasticity, has been developed. This approach has been satisfactorily validated by comparison with experimental and numerical results obtained by more accurate numerical models
The Competitive Diffusion of Gases in a Nanoporous Zeolite Using a Slice Selection Procedure
The study of the co-diffusion of several gases through a microporous solid and of the resulting
instantaneous distribution (out of equilibrium) of the adsorbed phases is particularly important in
many fields, such as gas separation, heterogeneous catalysis, etc. Classical H NMR imaging is a
good technique for visualizing these processes but, since the signal obtained is not specific for each
gas, each experiment has to be performed several times under identical conditions, and each time
with only one incompletely deuterated gas. In contrast, we have proposed a new NMR imaging
technique (based on the so-called NMR slice selection procedure) which gives a signal
characteristic of each adsorbed gas. It can therefore provide directly, at every moment and at every
level of the crystallite bed, the distribution of several gases competing in diffusion and adsorption.
Solutions to the direct and inverse problems are based on Heaviside’s operational method and
Laplace integral transformation. New procedures for identifying diffusion coefficients for co-
diffusing components (benzene and hexane) in intra- and intercrystallite spaces were implemented,
using high-speed gradient methods and mathematical diffusion models, as well as the NMR spectra
of the adsorbed mass distribution of each component in the zeolite bed. These diffusion coefficients
were obtained as a function of time for different positions along the bed. Benzene and hexane
concentrations in the inter- and intracrystallite spaces were calculated for every position in the bed
and for different adsorption times
Wilson-Polchinski exact renormalization group equation for O(N) systems: Leading and next-to-leading orders in the derivative expansion
With a view to study the convergence properties of the derivative expansion
of the exact renormalization group (RG) equation, I explicitly study the
leading and next-to-leading orders of this expansion applied to the
Wilson-Polchinski equation in the case of the -vector model with the
symmetry . As a test, the critical exponents and as well as the subcritical exponent (and higher ones) are estimated
in three dimensions for values of ranging from 1 to 20. I compare the
results with the corresponding estimates obtained in preceding studies or
treatments of other exact RG equations at second order. The
possibility of varying allows to size up the derivative expansion method.
The values obtained from the resummation of high orders of perturbative field
theory are used as standards to illustrate the eventual convergence in each
case. A peculiar attention is drawn on the preservation (or not) of the
reparametrisation invariance.Comment: Dedicated to Lothar Sch\"afer on the occasion of his 60th birthday.
Final versio
An Augmented OxRAM Synapse for Spiking Neural Network (SNN) Circuits
International audienceIn this paper, the conductance modulation of OxRAM memristive devices is evaluated based on experimental data to reveal the memristor inherent analog synaptic behavior. Simulation results are presented to validate the use of OxRAMs as synapses at a circuit level in a spiking neural network context. In the proposed approach, the OxRAM synapse is augmented with a shift register associated with current compliance control transistors to provide an efficient monitoring of the OxRAM conductance
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