2002

Universality of coupled Potts models

Vladimir S. Dotsenko 1, Jesper-Lykke Jacobsen 2, Xuan Son Nguyen 1, Raoul Santachiara 1 Nuclear Physics B 631 (2002) 426-446 We study systems of M Potts models coupled by their local energy density. Each model is taken to have a distinct number of states, and the permutational symmetry S_M present in the case of identical coupled models is thus broken initially. The duality transformations …

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Thermodynamics of small Fermi systems: quantum statistical fluctuations

Patricio Leboeuf 1, Alejandro Monastra 1 Annals of Physics 297 (2002) 127-156 We investigate the probability distribution of the quantum fluctuations of thermodynamic functions of finite, ballistic, phase-coherent Fermi gases. Depending on the chaotic or integrable nature of the underlying classical dynamics, on the thermodynamic function considered, and on temperature, we find that the probability distributions are dominated either …

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Theory of the ferroelectric phase in organic conductors: optics and physics of solitons

Serguei Brazovskii 1 Journal de Physique IV Colloque 12 (2002) 149 Recently the ferroelectric anomaly (Nad, Monceau, et al) followed by the charge disproportionation (Brown, et al) have been discovered in (TMTTF)2X compounds. The corresponding theory of the combined Mott-Hubbard state describes both effects by interference of the build-in nonequivalence of bonds and the spontaneous one of …

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Theory of pseudogaps in charge density waves in application to photo electron or tunneling spectroscopy

Serguei Matveenko 1, Serguei Brazovskii 2 Journal de Physique IV Colloque 12 (2002) 73 For a one-dimensional electron-phonon system we consider the photon absorption involving electronic excitations within the pseudogap energy range. In the framework of the adiabatic approximation for the electron – phonon interactions these processes are described by nonlinear configurations of an instanton type. We calculate the …

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The secondary structure of RNA under tension

Markus Muller 1, Florent Krzakala 1, Marc Mézard 1 European Physical Journal E 9 (2002) 67-77 We study the force-induced unfolding of random disordered RNA or single-stranded DNA polymers. The system undergoes a second order phase transition from a collapsed globular phase at low forces to an extensive necklace phase with a macroscopic end-to-end distance at high forces. At low temperatures, …

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The random K-satisfiability problem: from an analytic solution to an efficient algorithm

Marc Mézard 1, Riccardo Zecchina 2 Physical Review E: Statistical, Nonlinear, and Soft Matter Physics 66 (2002) 056126 We study the problem of satisfiability of randomly chosen clauses, each with K Boolean variables. Using the cavity method at zero temperature, we find the phase diagram for the K=3 case. We show the existence of an intermediate phase in the …

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The Local Time Distribution of a Particle Diffusing on a Graph

Alain Comtet 1, 2, Jean Desbois 1, Satya N. Majumdar 3 Journal of Physics A 35 (2002) L687-L694 We study the local time distribution of a Brownian particle diffusing along the links on a graph. In particular, we derive an analytic expression of its Laplace transform in terms of the Green’s function on the graph. We show that the asymptotic behavior of this …

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The Local and the Occupation Time of a Particle Diffusing in a Random Medium

Satya N. Majumdar 1, Alain Comtet 2, 3 Physical Review Letters 89 (2002) 060601 We consider a particle moving in a one dimensional potential which has a symmetric deterministic part and a quenched random part. We study analytically the probability distributions of the local time (spent by the particle around its mean value) and the occupation time (spent above its mean …

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The Combinatorics of Alternating Tangles: from theory to computerized enumeration

Jesper-Lykke Jacobsen 1, Paul Zinn-Justin 1 NATO Science series II: Mathematics, physics and chemistry 73 (2002) 33-45 We study the enumeration of alternating links and tangles, considered up to topological (flype) equivalences. A weight $n$ is given to each connected component, and in particular the limit $n\to 0$ yields information about (alternating) knots. Using a finite renormalization scheme for …

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