Statistical Mechanics is a traditional subject in Florence, which
has been accounted for by this 19-year old INFN initiative. 
All the people have a quantum field theory background, and thus have been
investigating the fruitful relations and analogies among statistical
mechanics, condensed matter and particle physics.
The main theme is the study of exactly solvable models in two dimensions, 
namely the conformal field theories and the integrable systems,
and their application to statistical mechanics and condensed matter problems.
Exact solutions provide the tools to understand many physical problems 
which are characterized by strong interactions and non-perturbative effects. 
These same problems are also investigated by a variety of numerical methods,
and the comparison between the two approaches can often be done.

There is a rather broad spectrum of strongly-interacting systems in
statistical mechanics, and, similarly, there are many subjects 
analyzed by the participants of this INFN Initiative.
Among others, let us mention the quantum Hall effect and in general
the strongly-interacting electron systems in low dimension,
the random and disordered systems, the open systems out of equilibrium, 
the many-body dynamical systems and the approach to equilibrium near 
a phase transition.

The exactly solvable field theories in two-dimensions can also be 
applied to rather different domains, like the model building 
in String Theory (here condensed-matter analogies have been very fruitful). 
Another use of exact solutions is for testing fundamental aspects of 
field theory such as the irreversibility of the renormalization-group 
flow (the c-theorem).

The main interests of the participants are:

Florence
--------
A. Cappelli: conformal field theories applied to condensed matter and
statistical mechanics;

F. Colomo: quantum field theories and integrable systems
applied to condensed matter and statistical mechanics;

G. D'Appollonio: conformal field theory applied to condensed matter and
string theory;

M. Zabzine: as above;

M. Pettini: statistical mechanics and dynamical systems with many degrees
of freedom;

F. Bagnoli: as above;

S. Ruffo: as above;

Genova
------
N. Magnoli: conformal field theories and integrable systems
applied to condensed matter and statistical mechanics; 

Trieste
-------
D. Fioravanti: conformal field theories and integrable systems
applied to condensed matter and statistical mechanics; 

G. Mussardo: as above;

G. Delfino: as above;

Controzzi, Mossa, Mosconi: as above;

A. Cappelli is asking 3KEuro for inviting G.R. Zemba
(Univ. di Buenos Aires) for 2 months for collaborating on
``effective field theories of the quantum Hall effect''

G. Mussardo is asking 1KEuro for inviting A. LeClair
for one month for collaboration on ``boundary integrable
conformal field theories''

 FIRENZE FI11 2002 PROGRAM
 =========================

 - A. Cappelli, G.R. Zemba; 
 ``Conformal field theories for the quantum Hall effect''
   Explore the physical consequences of the previously proposed
   W-infinity symmetry. Study the description offered by the non-commutative
   Chern-Simons field theory recently proposed by L. Susskind.

 - A.Cappelli, G. D'Appollonio 
 ``Boundary conformal field theories''
   Determine the boundary states by a generalized orbifold
   construction; develop a Landau-Ginzburg description of the boundary 
   states and of the boundary renormalization-group flows.
   Proof that the boundary entropy monotonically decreases along these flows.

- F. Colomo
 ``Frustated models and q-oscillators''
  Study of statistical models with frustration and no quenched disorder;
  possible applications of the q-deformed algebras to solve exactly
  statistical models with frustration. Application of the q-deformed
  oscillator to non trivial combinatorial problems.

- M. Pettini, R. Franzosi, L. Casetti, L. Spinelli, R. Gatto, M. Cerutti-Sola
 ``Phase transitions and the topology changes in configuration space''
   The equi-potential sub-manifolds of the configuration space of an 
   Hamiltonian system undergo a topology change in correspondence of a 
   phase transition. We have studied further occurrences of this
   phenomenon which has been analysed over the last few years.
   We have published a review article with a complete account of it.

 - S. Ruffo, V. Latora and A. Rapisarda;
 ``Dynamics in statistical models near the phase transition''
   We derived scaling properties of the largest Lyapunov exponent in
   the thermodynamic limit. We shall continue to investigate dynamics
   in other systems.

-  S. Ruffo, J. Barre', T. Dauxois, P. Holdsworth, P. Mukamel;
 ``Dynamics and statistics in certain statistical models''
   We showed the presence of a localized structure in a system with long
   range interaction and conserved total energy, which is incompatible
   with the canonical ensemble. We analysed the localized structure 
   observed in the previous paper in terms of the forced Burgers equation.

-  F. Bagnoli, F. Cecconi;
 ``Non-predictibility of non-chaotic systems and syncronization''
   We consider systems with negative Lyapunov exponents but with
   "chaotic" response to a finite perturbation. We want to characterize
   such behaviors using syncronization techniques which are useful for
   experiments.

-  F. Bagnoli, N. Boccara, R. Rechman;
 ``Phase transitions in cellular automata''
   Continue the study of cellular automata with adsorbing states.

-  F. Bagnoli, F. Bochiccio, S. Bucci;
 ``Models for the sensitivity of passive radon detectors''
   Passive radon detectors are widely used for large-scale epidemic
   studies; we participate to a research project for deducing
   their sensitivity as a function of the specific features of
   detector, such that the geometry, the thicknes of the adsorber etc.



 PREPRINTS
 ==========
A. Cappelli, R. Guida, N. Magnoli,
``Exact Consequences of the Trace Anomaly in Four Dimensions '',
preprint hep-th/0103237 , Nucl. Phys B to appear

M. Antoni, H. Hinrichsen and S. Ruffo: "On the microcanonical 
solution of a system of fully coupled particles", preprint, to be
published on Chaos, solitons and fractals, (2001). 

S. Lepri and S. Ruffo:"Dynamics of the magnetization vector 
of the XY-model", preprint, to be published on Europhys. Lett. (2001).

R. Khomeriki, S. Lepri and S. Ruffo:"Pattern formation and 
localization in the forced-damped FPU lattice", preprint, submitted
to Phys. Rev. E (2001).

J. Barre', D. Mukamel and S. Ruffo:"Inequivalence of
ensembles in a system with long range interactions", preprint, to be
published on Phys. Rev. Lett. (2001).

H. Larralde, F. Leyvraz, G. Martinez-Mekler, R. Rechtman and
S. Ruffo:"Transport properties of the diluted Lorentz slab", preprint, 
to be published on Phys. Rev. E, (2001).

F. Leyvraz and S. Ruffo:"Ensemble Inequivalence: A Formal
Approach", preprint, to be published on Physica A (2001).

F. Leyvraz and S. Ruffo: "Ensemble Inequivalence in Systems 
with Long-range Interactions", preprint, submitted to J. Phys. A (2001).

D. Fanelli and S. Ruffo:"Self-gravitating spherical shell
systems and globular clusters", to be published on Physica A (2001).

M.-C. Firpo and S. Ruffo:"Chaos suppression in the large 
size limit for long-range systems", preprint, submitted to J. Phys. A
(2001).

F.Bagnoli, F.Bochicchio and S.Bucci, 
"Further studies on sensitivity of a LR-115 based radon dosemeter",
preprint (2000). 

L. Casetti, E. G. D. Cohen, Marco Pettini,
"Phase transitions as topology changes in configuration space: 
an exact result",
preprint cond-mat/0104267



 PROCEEDINGS
 ===========

A. Cappelli, G. D'Appollonio, R. Guida, N. Magnoli, 
``On the c-theorem in more than two dimensions'',
Proceedings of ``Nonperturbative Quantum Effects 2000'', 
Paris, 7-13 Sep 2000, JHEP proceedings (2000)

V. Latora, A. Rapisarda and S. Ruffo: 
"Chaos in the thermodynamic limit", 
Int. Conf. "Let's face Chaos Through Nonlinear Dynamics" 
Maribor (Slovenia) 27 june - 11 july 1999,
Progress of Theoretical Physics Supplement, 139, 204 (2000).

S. Ruffo, "Time-scales for the approach to thermal
equilibrium", in "Chance in Physics: Foundations and Perspectives",
J. Bricmont et al. eds., Springer, (2001).

O.Antolin, F.Bagnoli, R.Bulajich, J.A.Gomez and A.Rechtman (eds.),
"Problemas para la 14$^a$ olimpiada de Matem\'aticas", 
Sociedad Matematica Mexicana (2000).

F.Bagnoli, S.Ruffo, eds. ,
"Dinamical Modeling in Biotechnologies",
World Scientific, Singapore 2001, which includes:

F.Bagnoli, P.Palmerini and N.Boccara, 
"Phase Transitions in a Probabilistic Cellular Automaton with Two
Absorbing States" 

F.Bagnoli, "Cellular Automata"

M. Pettini, R. Franzosi, L. Spinelli,
"Topology and Phase Transitions: towards a proper mathematical definition
of finite N transitions", Bologna 2000 - Structure of the Nucleus at 
the Dawn of the Century, International Conference, M. Bruno, A. Ventura,
D. Vretenar Eds., World Scientific 

GENOVA FI11 2002 PROGRAM
========================

- N. Magnoli, R. Guida and G. Watts
- N. Magnoli, M. Caselle and P. Grinza
``Study of statistical models near criticality by using field theory''
Study of the equation of state of the Ising model in two dimensions;
comparison of analytic and numerical correlation functions in a magnetic field.

- N. Magnoli, A. Cappelli and R. Guida
``Renormalization of the stress tensor in four dimensions and extension of 
  the c-theorem''
  We found the general form of the stress-tensor 3-p. function;
  we plan to investigate the consequences of N=1 supersymmetry.


PREPRINTS
=========

 M.Caselle, P.Grinza, N.Magnoli,
"Correction induced by irrelevant operators in the correlators of the 
2d Ising model in a magnetic field",
preprint hep-th/0103263

NEW RESEARCHERS
===============
Davide Controzzi will join the group in the Fall 2001
as postdoc of SISSA
Valentina Riva, Paola Mosconi and Alessandro Mossa
will join as graduate students of Sissa


TRIESTE FI11 2002 PROGRAM
=========================

- G. Mussardo and collaborators.
``Supersymmetry in Statistical Models''
  Exact calculation of the matrix elements and correlators of order
  parameters in statistical models which present supersymmetry in
  their continuum limit.

``Non-integrable Quantum Field Theory''
  Study of the spectrum of a statistical model for a generic point 
  of a phase diagram; applications of the double Sine Gordon model.

``Boundary Field Theory and surface phase diagrams''
  Study of the physical effects in field theories and strongly correlated
  systems induced by the boundary conditions imposed on the order parameters.

``Quantum Field Theory at Finite Temperature''
  Study of finite temperature effects in physical systems 
  described by quantum field theories; contiune the determination of
  two and higher point functions from the TBA data and the form factors

``Universal ratios of the Renormalization Group''


- A. Delfino,
``Phases of antiferromagnetic spin systems''


PREPRINTS
=========
Giuseppe Mussardo,
ON THE FINITE TEMPERATURE FORMALISM IN INTEGRABLE QUANTUM FIELD THEORIES.
preprint hep-th/0103214 

Davide Fioravanti, Marco Rossi, 
"A braided Yang-Baxter Algebra in a Theory of two coupled Lattice Quantum KdV:
 algebraic properties and ABA representations", 
to appear in Comm. Math. Phys.



PROCEEDINGS
===========

Giuseppe Mussardo,
UNIVERSAL RATIOS OF THE RENORMALIZATION GROUP,
proceedings of ``Nonperturbative quantum effects 2000'',
Paris, 7-13 Sept 2000, JHEP proceedings 2000

D. Fioravanti, 
"HIDDEN VIRASORO SYMMETRY OF THE SINE-GORDON THEORY",
Published in JHEP, "Paris 2000, Non-perturbative quantum effects", (2000), 43