ICTP - The Abdus Salam International Centre for Theoretical Physics, Trieste, Italy

CM Research Profile
Statistical Physics and Complex Systems

Statistical Physics and Complex Systems

1. The statistical mechanics and dynamics of topological excitations in nonlinear systems (S. Shenoy)

The well-known 2D Kosterlitz-Thouless vortex-point unbinding transition in 2D XY models and superconducting films, has been generalized to 3D XY and layered superconductor models, where a vortex-loop blowout destroys phase coherence. Other vortex related issues are quantum fluctuations in Josephson junction arrays and superconductors, and current drive effects, including an understanding of nonlinear I-V characteristics, vortex-loop-induced transformer effects and a Magnus force on vortices.

2. Statistical physics of frustrated systems (S. Franz, A. Maritan, R. Zecchina)

Systems studied in this area are disordered systems, such as spin glasses, manifolds in random media, etc. as well as systems without intrinsic disorder as structural glasses. Applications include optimization and protein folding.

3. Chaotic behavior of coupled map lattices (H. Cerdeira)

The behavior of global coupling in nonlinear systems with a large number of elements is studied in the thermodynamic limit. This class of complex systems is of considerable importance in modeling phenomena as diverse as Josephson junction arrays, vortex dynamics in fluids, and even evolutionary dynamics, biological information processing and neurodynamics. The ubiquity of globally coupled phenomena has thus made it a focus of much research activity.

4. Nonequilibrium Critical Phenomena (A. Maritan, M. Marsili,L. Pietronero, A. Vespignani)

The large scale behavior and statistical properties of systems which are close to critical points are studied. Among these are phase transitions associated with nonequilibrium states, self-organized criticality, fractal growth phenomena and a vast class of complex systems in which information spreads over a wide range of length and time scales.

5. Statistical Mechanics (R. Zecchina)

We deal with the issue of generalizing combinatorial approaches to the planar Ising model, i.e. the dimer covering method, to models defined over lattices of arbitrary topological genus.

6. Interdisciplinary Issues (S. Franz, M. Marsili, L. Pietronero, A. Vespignani, R. Zecchina)

We are developing studies at the interfaces between statistical physics and other areas such as computer science, biology, geology and economics.