Dynamical Phase Transitions for Fluxes of Mass on Finite Graphs

We study the time-averaged flux in a model of particles that randomly hop on a finite directed graph. In the limit as the number of particles and the time window go to infinity but the graph remains finite, the large-deviation rate functional of the average flux is given by a variational formulation involving paths of the density and flux. We give sufficient conditions under which the large deviations of a given time averaged flux is determined by paths that are constant in time. We then consider a class of models on a discrete ring for which it is possible to show that a better strategy is obtained producing a time-dependent path. This phenomenon, called a dynamical phase transition, is known to occur for some particle systems in the hydrodynamic scaling limit, which is thus extended to the setting of a finite graph

Experimental Constraints on the Neutralino-Nucleon Cross Section

In the light of recent experimental results for the direct detection of dark matter, we analyze in the framework of SUGRA the value of the neutralino-nucleon cross section. We study how this value is modified when the usual assumptions of universal soft terms and GUT scale are relaxed. In particular we consider scenarios with non-universal scalar and gaugino masses and scenarios with intermediate unification scale. We also study superstring constructions with D-branes, where a combination of the above two scenarios arises naturally. In the analysis we take into account the most recent experimental constraints, such as the lower bound on the Higgs mass, the $b\to s\gamma$ branching ratio, and the muon $g-2$.Comment: References added, bsgamma upper bound improved, results unchanged, Talk given at Corfu Summer Institute on Elementary Particle Physics, August 31-September 20, 200

Level 2.5 large deviations for continuous time Markov chains with time periodic rates

We consider an irreducible continuous time Markov chain on a finite state space and with time periodic jump rates and prove the joint large deviation principle for the empirical measure and flow and the joint large deviation principle for the empirical measure and current. By contraction we get the large deviation principle of three types of entropy production flow. We derive some Gallavotti-Cohen duality relations and discuss some applications.Comment: 37 pages. corrected versio

Chargino contributions to the CP asymmetry in B -> Phi K(S) decay

We perform a model independent analysis of the chargino contributions to the CP asymmetry in B -> Phi K(S) process. We use the mass insertion approximation method generalized by including the possibility of a light right-stop. We find that the dominant effect is given by the contributions of the mass insertions deltaU_LL(32) and deltaU_RL(32) to the Wilson coefficient of the chromomagnetic operator. By considering both these contributions simultaneously, the CP asymmetry in B -> Phi K(S) process is significantly reduced and negative values, which are within the 1-sigma experimental range and satisfy the b -> s gamma constraints, can be obtained.Comment: 14 pages, LaTeX, 3.eps Figure

Onsager reciprocity relations without microscopic reversibility

In this paper we show that Onsager--Machlup time reversal properties of thermodynamic fluctuations and Onsager reciprocity relations for transport coefficients can hold also if the microscopic dynamics is not reversible. This result is based on the explicit construction of a class of conservative models which can be analysed rigorously.Comment: revtex, no figure

L’accès des PME aux financements bancaires.

Les conditions d’accès des PME au crédit se sont plutôt améliorées ces dernières années. Des handicaps persistent néanmoins (cherté relative des découverts bancaires, contraintes de financement propres à certains secteurs) dans un contexte financier devenu moins accommodant sur la période récente.Coût du crédit, taux d’intérêt bancaires, taux débiteurs, usure, PME, entrepreneurs individuels, risque de crédit, risque de défaut, conditions de financement, financement des entreprises, distribution du crédit, capital-investissement, notation, cotation, FIBEN, évaluation des entreprises, exigences de fonds propres.