Nonequilibrium dynamics of fully frustrated Ising models at T=0

We consider two fully frustrated Ising models: the antiferromagnetic triangular model in a field of strength, $h=H T k_B$, as well as the Villain model on the square lattice. After a quench from a disordered initial state to T=0 we study the nonequilibrium dynamics of both models by Monte Carlo simulations. In a finite system of linear size, $L$, we define and measure sample dependent "first passage time", $t_r$, which is the number of Monte Carlo steps until the energy is relaxed to the ground-state value. The distribution of $t_r$, in particular its mean value, $$, is shown to obey the scaling relation, $\sim L^2 \ln(L/L_0)$, for both models. Scaling of the autocorrelation function of the antiferromagnetic triangular model is shown to involve logarithmic corrections, both at H=0 and at the field-induced Kosterlitz-Thouless transition, however the autocorrelation exponent is found to be $H$ dependent.Comment: 7 pages, 8 figure

Degeneracy Algorithm for Random Magnets

It has been known for a long time that the ground state problem of random magnets, e.g. random field Ising model (RFIM), can be mapped onto the max-flow/min-cut problem of transportation networks. I build on this approach, relying on the concept of residual graph, and design an algorithm that I prove to be exact for finding all the minimum cuts, i.e. the ground state degeneracy of these systems. I demonstrate that this algorithm is also relevant for the study of the ground state properties of the dilute Ising antiferromagnet in a constant field (DAFF) and interfaces in random bond magnets.Comment: 17 pages(Revtex), 8 Postscript figures(5color) to appear in Phys. Rev. E 58, December 1st (1998

Random Matrix Theory and higher genus integrability: the quantum chiral Potts model

We perform a Random Matrix Theory (RMT) analysis of the quantum four-state chiral Potts chain for different sizes of the chain up to size L=8. Our analysis gives clear evidence of a Gaussian Orthogonal Ensemble statistics, suggesting the existence of a generalized time-reversal invariance. Furthermore a change from the (generic) GOE distribution to a Poisson distribution occurs when the integrability conditions are met. The chiral Potts model is known to correspond to a (star-triangle) integrability associated with curves of genus higher than zero or one. Therefore, the RMT analysis can also be seen as a detector of ``higher genus integrability''.Comment: 23 pages and 10 figure

Random walks and polymers in the presence of quenched disorder

After a general introduction to the field, we describe some recent results concerning disorder effects on both `random walk models', where the random walk is a dynamical process generated by local transition rules, and on `polymer models', where each random walk trajectory representing the configuration of a polymer chain is associated to a global Boltzmann weight. For random walk models, we explain, on the specific examples of the Sinai model and of the trap model, how disorder induces anomalous diffusion, aging behaviours and Golosov localization, and how these properties can be understood via a strong disorder renormalization approach. For polymer models, we discuss the critical properties of various delocalization transitions involving random polymers. We first summarize some recent progresses in the general theory of random critical points : thermodynamic observables are not self-averaging at criticality whenever disorder is relevant, and this lack of self-averaging is directly related to the probability distribution of pseudo-critical temperatures $T_c(i,L)$ over the ensemble of samples $(i)$ of size $L$. We describe the results of this analysis for the bidimensional wetting and for the Poland-Scheraga model of DNA denaturation.Comment: 17 pages, Conference Proceedings "Mathematics and Physics", I.H.E.S., France, November 200

Regimen sanitatis Salernitanu[m] necno[n] [et] m[a]g[ist]ri Arnoldi d[e] Noua Villa feliciter i[n]cipit. [Incipit Liber de conseruatione corporis, seu de regimine sanitatis, co[m]positus per magistrum Arnoldu[m] de Villa Noua]. [Enquadernació]

Doble requadre a base de filets i fils decorats amb diferents ferros d’estil mudèjar. Al rectangle vertical central, dividit en tres compartiments (rectangles horitzontals), decoració a base de llaços mudèjars. Al centre, l’escut de Sant Jordi amb la creu roja en mosaic de pell. Llom amb nervis i decoració similar als plans. Cants, contracants i talls daurats

Libro de Sant Iuan Climaco llamado Escala spiritual. Joan Clímac. En el qual se descriuen treynta escalones por donde pueden subir los hombres a la cumbre de la perfection. Sant Joan Clímac. [Enquadernació]

Combinació de llaços d’aquest estil, amb mosaics de diferents colors molt llampants. Els ferros, plens i atzurats. Al centre, composició daurada de fils, petits ferros i punts. Cantells, contracantells i talls daurats

Segon del Cartoxa, Lo. Ludolf de Saxònia. [Enquadernació]

Una franja de pell vermella, amb una roda daurada, emmarquen una composició geomètrica a base de franja de mosaic blanc. Ferros “pleins azurées”, al centre oval de mosaic verd amb doble fil d’or, embolcallen el super-libris de Joaquim Montaner, amb puntillat daurat. Llom amb nervis, fils, ferros i mosaic. Autor, títol, lloc i any d’edició daurats. Talls, cantells i contracantells daurat

Peccador remut. Felip de Malla. [Enquadernació]

Una sèrie de fils paral·lels concèntrics formen un rectangle central. Entre aquests fils, un rivetat a base de ferros estil Renaixement, amb ferros d’angles. Al rectangle central, ferros, punts, fils, flors i rodes formen un conjunt decoratiu. Super-libris de Joaquim Montaner a base de mosaic blau i vermell amb daurats. Encercla el super-libris una palmatòria de llorer. Llom amb nervis decorats amb fils gofrats. Entrenervis amb ferro gofrat. Autor, títol, lloc i any d’edició gofrats. Talls, cantells i contracantells daurat

Commentum familiare in Ciceronis Officia. Cu[m] Petri Marsi exactissima explanatione ab ipso recognita et diligenter annotata cumq[ue] De amicitia, Senectute et Paradoxis eiusde[m] Ciceronis non penitendis commentarijs [et] omnium tum rerum tum verborum indice. Marc Tul·li Ciceró. [Enquadernació]

Doble banda rectangular concèntrica decorada amb ferros de llaços mudèjars. Als angles florons daurats. Al rectangle central, un rombe amb decoració interior a base de ferros mudèjars gofrats i punts daurats. Al llom, nervis i decoració similar a les tapes. Autor, títol, lloc i any d’edició. Cantells, contracantells i talls daurats