publications

Olivier Brodier 1, Peter Schlagheck 1, Denis Ullmo 1 Physical Review Letters 87 (2001) 064101 Dynamical tunneling between symmetry related invariant tori is studied in the near-integrable regime. Using the kicked Harper model as an illustration, we show that the exponential decay of the wave functions in the classically forbidden region is modified due to coupling processes that are mediated by […]

Irene Giardina 1, Jean-Philippe Bouchaud 2, Marc Mézard 3 Journal of Physics A 34 (2001) L245-L252 We investigate the competition between barrier slowing down and proliferation induced superdiffusion in a model of population dynamics in a random force field. Numerical results in $d=1$ suggest that a new intermediate diffusion behaviour appears. We introduce the idea of proliferation assisted barrier crossing and

Eugene Bogomolny 1, Olivier Giraud 1, Charles Schmit 1 Communications in Mathematical Physics 222 (2001) 327-369 The 2-point correlation form factor, $K_2(\tau)$, for small values of $\tau$ is computed analytically for typical examples of pseudo-integrable systems. This is done by explicit calculation of periodic orbit contributions in the diagonal approximation. The following cases are considered: (i) plane billiards in the form

Xavier Campi 1, Hubert Krivine 1, Nicolas Sator 1 Physica A 296 (2001) 24-30 We predict that self-bound clusters of particles exist in the supercritical phase of simple fluids. These clusters, whose internal temperature is lower than the global temperature of the system, define a percolation line that starts at the critical point. This line should be physically observable. Possible experiments

Stéphane Ouvry 1 Physics Letters B 510 (2001) 335 In order to achieve a dimensional reduction from dimension two to one not only in phase space but also in configuration space, the lowest Landau level (LLL) projection is not sufficient. One has also, in the LLL, to take the vanishing magnetic field limit, a procedure which can

Sergei K. Nechaev 1, 2, Raphael Voituriez 1 Journal of Physics A 34 (2001) 11069-11082 he stable profile of the boundary of a plant’s leaf fluctuating in the direction transversal to the leaf’s surface is described in the framework of a model called a ‘surface à godets’. It is shown that the information on the profile is encoded in the Jacobian

Jean-Philippe Bouchaud 1, 2, Irene Giardina 3, Marc Mézard 4 Quantitative Finance 1 (2001) 212-216 We propose a general interpretation for long-range correlation effects in the activity and volatility of financial markets. This interpretation is based on the fact that the choice between `active’ and `inactive’ strategies is subordinated to random-walk like processes. We numerically demonstrate our scenario in the framework of

Alain Comtet 1, Sergei K. Nechaev 1, Raphael Voituriez 1 Journal of Statistical Physics 102 (2001) 203-230 We introduce a deterministic model defined on a two dimensional hyperbolic lattice. This model provides an example of a non random system whose multifractal behaviour has a number theoretic origin. We determine the multifractal exponents, discuss the termination of multifractality and conjecture the geometric origin

Irene Giardina 1, Jean-Philippe Bouchaud 2, 3, Marc Mézard 4 Physica A 299 (2001) 28-39 We propose a general interpretation for long-range correlation effects in the activity and volatility of financial markets. This interpretation is based on the fact that the choice between `active’ and `inactive’ strategies is subordinated to random-walk like processes. We numerically demonstrate our scenario in the framework of

Markus Muller 1, 2, Denis A. Gorokhov 1, 3, Gianni Blatter 1 Physical Review B 64 (2001) 134523 We analyze the competition between thermal fluctuations and pinning of vortices in bulk type II superconductors subject to point-like disorder and derive an expression for the temperature dependence of the pinning length L_c(T) which separates different types of single vortex wandering. Given a disorder potential with