1,720,996 research outputs found
Non-Convex Multipartite Ferromagnets
No full textWe investigate a multipartite ferromagnetic model without self-interactions between spins of the same party, so that the Hamiltonian is not a definite quadratic form of the magnetisations. We find the free energy and study the phase transition for all zero external fields. Moreover in the bipartite case we analyse the fluctuations of the rescaled magnetisations, below and at the critical point, and we study the phase transitions with non-zero magnetic fields
Invariant measures for the periodic derivative nonlinear Schrödinger equation
Get PDFWe construct invariant measures associated to the integrals of motion of the periodic derivative nonlinear Schrödinger equation (DNLS) for small data in L2 and we show these measures to be absolutely continuous with respect to the Gaussian measure. The key ingredient of the proof is the analysis of the gauge group of transformations associated to DNLS. As an intermediate step for our main result, we prove quasi-invariance with respect to the gauge maps of the Gaussian measure on L2 with covariance (I+(−Δ)k)−1 for any k⩾2
Superficial epigastric vein sparing in the saphenous-femoral crossectomy or in the closures of the saphena magna
No full textEvaluation of different ruminal boluses with passive transponder for animal identification
No full textGibbs measures associated to the integrals of motion of the periodic derivative nonlinear Schrödinger equation
Get PDFWe study the one-dimensional periodic derivative nonlinear Schrödinger equation. This is known to be a completely integrable system, in the sense that there is an infinite sequence of formal integrals of motion ∫hk , k∈Z+. In each ∫h2k the term with the highest regularity involves the Sobolev norm H˙k(T) of the solution of the DNLS equation. We show that a functional measure on L2(T) , absolutely continuous w.r.t. the Gaussian measure with covariance (I+(−Δ)k)−1, is associated to each integral of motion ∫h2k , k≥1
Electronic animal identification using a passive transponder: evaluation of different ruminal boluses
No full textPeriodic Driving at High Frequencies of an Impurity in the Isotropic XY Chain
No full textWe study the isotropic XY chain with a transverse magnetic field acting on a single site and analyse the long time behaviour of the time-dependent state of the system when a periodic perturbation drives the impurity. We find that for high frequencies the state approaches a periodic orbit synchronised with the forcing and provide the explicit rate of convergence to the asymptotics
A mechanical approach to mean field spin models
No full textInspired by the bridge pioneered by Guerra among statistical mechanics on lattice and analytical mechanics on 1+1 continuous Euclidean space time, we built a self-consistent method to solve for the thermodynamics of mean field models defined on lattice, whose order parameters self-average. We show the whole procedure by analyzing in full detail the simplest test case, namely, the Curie-Weiss model. Further, we report some applications also to models whose order parameters do not self-average by using the Sherrington-Kirkpatrick spin glass as a guide
Risultati preliminari sulla valutazione delle prestazioni operative di due decanter industriali per l’estrazione olearia. [Preliminary results in the comparison of two decanter centrifuge for the oil extraction]
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