Theoretical physics
PROFESSORS
Giovanni Maria Prosperi
Renzo Cirelli
Luciano Girardello
Ludovico Lanz
Giuseppe Marchesini
Ruggero Ferrari
Emilio Montaldi
Angelo Loinger (fuori ruolo)
Rodolfo Bonifacio
ASSOCIATE PROFESSORS
Vittorio Berzi
Vincenzo Benza
Claudio Destri
Mirella Enriotti
Franco Gallone
Cesare Maroli
Guido Parravicini
Giovanna Ramella
Antonio Sparzani
Daniela Zanon
RESEARCH ASSOCIATES
Maria Cristina Abbati
Bruno Bassetti
Marcattilio Comi
Giancarlo Lupieri
Alessandro Mania'
Antonio Zecca
Luca Molinari
Silvia Penati
Vittoria Petrillo
Mario Raciti
Franco Riva
Fausto Valz Gris
INFN RESEARCH ASSOCIATES
Paolo Butera
Emilio Del Giudice
Paolo Nason
Mario Pernici
Yuri L. Dokshitzer
POSTDOCTORAL FELLOWS
Mauro Zeni
Nora Brambilla
Andrea Pasquinucci
Massimo Scorletti
Paolo Soriani
Raffaella Burioni
Gavin Salam (INFN)
Michela Petrini
ADMINISTRATIVE STAFF
Maria Lorena Caraffa
Quantum fields theory and strings
String theory and Quantum field theory (QFT)
- String theory seems to be, by now, the first plausible and consistent approach
to quantum gravity and hence to the unification of gravity with matter. In this
perspective the research has been focused on the relation between the
microscopic aspects (2D conformal QFT, representing the evolution of the
string, i.e. the string vacua) and the macroscopic aspects (i.e. the effective QFT
as low energy limit). Attention has been given to the recent issue of dualities;
evidence has been given in favour of electric-magnetic duality, i.e. between the
weak coupling regime and the strong coupling one in N=4 super Yang-Mills
theories and in string theories of type II. A mechanism for partial spontaneous
breaking of extended local gauge groups have been constructed. A book has
been written on QFT and string theories with N=2 supersymmetry. Among other
results in perturbayive string theory, the PCT theorem for strings has been
proven. (Luciano Girardello, Paolo Soriani, Andrea Pasquinucci)
- One interesting topic of recent research in string theory has been the study of
the relationship between renormalization group and string dynamics. To ensure
consistent string propagation in the classical backgrounds one must insist on
the conformal invariance of the underlying two-dimensional theory. In this
context renormalization group properties have been studied for quantum field
theories in 1+1 dimensions with and without boundaries (open and closed
strings, correspondingly), with and without induced two-dimensional gravity.
Correlation functions in topological 2D theories have also been investigated.
(Daniela Zanon, Silvia Penati)
1. Girardello, A. Giveon, M. Porrati & A. Zaffaroni, "S duality in N=4 Yang-
Mills with general gauge groups", Nucl. Phys. B448 (1995), 127
2. Anselmi, P. Frè, L. Girardello and P. Soriani, " From N=2 theories to
constrained moduli space", Nucl. Phys. (Proc Suppl.) B41 (1995) 29
3. Frè and P. Soriani, "The N=2 wonderland, from Calabi-Yau manifold to
topological field theories", (1995) World Scientific
4. Girardello, A. Giveon, M. Porrati and A. Zaffaroni, "S duality in N=4 super
Yang-Mills Theories With general gauge group", Nucl. Phys. B448 (1995)
127
5. Girardello, M. Porrati, and A. Zaffaroni, "Heterotic type II string duality
and the H monopole problem" Int. Journal of Modern Physics A23
(1996),155
6. Frè, L. Girardello, I. Pesando, M. Trigiante, “Spontaneous N=2 to N=1
local supersymmetry breaking with surviving compact gauge groups”, to
be published in Nucl. Phys. B
7. Ferrara, L. Girardello and M. Porrati, “Minimal Higgs branch for the
breaking of half of the supersymmetries in N=2 supergravity”, Phys. Lett.
B336 (1996), 155
8. Ferrara, L. Girardello and M. Porrati, “Spontaneous breaking of N=2 to N=1
in rigid and local supersymmetric theories”, Phys. Lett. B376 (1996), 275
9. Penati and D. Zanon, "Topological correlation functions in Minkowski
spacetime”, Nuclear Physics B436 (1995), 265
10. Penati and D. Zanon, "Quantum integrability in two-dimentional systems
with boundary", Physics Letters B358 (1995), 63.
11. Penati, A. Refolli and D. Zanon, "Quantum boundary currents for nonsimply-
laced Toda theories", IFUM-518-FT, Physics Letters B369 (1996), 16.
12. Penati, A. Refolli and D.Zanon, "Classical versus quantum symmetries for
Toda theories with a nontrivial boundary perturbation", Nuclear Physics B470
[FS] (1996), 396.
13. Penati, A. Santambrogio and D. Zanon, "Renormalization group flows in
sigma-models coupled to two-dimentional dynamical gravity", IFUM-528-FT,
Maggio 1996, in via di pubblicazione su Nuclear Physics B.
14. Penati, A. Santambrogio and D. Zanon, "Sigma-models coupled to two
dimentional gravity", nei Proceedings della conferenza "Second International
Sakharov Conference on Physics", Mosca 20-24 Maggio 1996
15. A.Pasquinucci and K. Roland, "On the Computation of one-loop amplitudes
with external fermions in 4d heterotic superstrings", Nuclear Physics B440,
pag. 441-494, 54 pp., Amsterdam, (April 1995 )
16. Pasquinucci and K. Roland, "Bosonization of world-sheet fermions in
Minkowski space-time", Physics Letter B351, pag. 131-136
17. Pasquinucci and K. Roland, "On the Normalization and Hermeticity of
Amplitudes in 4D Heterotic Superstrings", Nuclear Physics B457, pag. 27-56,
30pp., Amsterdam, December 1995
18. Pasquinucci and K. Roland, "CPT Invariance of String Models in a Minkowski
Background", Nuclear Physics B473, pag. 31.62, 31pp., Amsterdam, August
1996
19. Pasquinucci and K. Roland, " String Theory and CPT Theorem on the World-
Sheet", Nuclear IFUM-534/FT, NBI-HE-96-32, to be in published in Nuclear
Physics B.
20. Pasquinucci and K. Roland, "Scattering Amplitudes and the CPT Theorem in
String Theory", proceedings of the Conference "Gauge Theories, Applied
Suparsymmetry and Quantum Gravity", Imperial College, London, July 1996,
preprint IFUM-543/FT, NBI-HE-96-63
Exact renormalization group
Exact Wilson renormalization group is studied in non-Abelian gauge theories,
chiral theory and matter field on a lattice. A resummation of perturbative
graphs is attempted which leads to a running coupling. Action which are
invariant at the ultraviolet cutoff are introduced.
(Giuseppe Marchesini, Mario Pernici, Mario Raciti, Franco Riva)
1. M.Bonini, G. Marchesini and M.. Simionato, "Perturbative infrared Beta
function and infrared renormalons in the exact Wilson renormalization
group in Yang-Mills theory", Nuclear Physics B, to be published
2. M. Pernici, M. Raciti, F. Riva, “Renormalization of matter field theories on
the lattice and the flow equation”, Nucl. Phys. B458 (1996), 355
3. M. Pernici, “Chiral invariance and lattice fermions with minimal doubling”
Phys. Lett. B346 (1995) 99
4. M. Bonini and G.Marchesini, "Gauge invariant action at the ultraviolet
cutoff",Physics Letters B, to be published
5. M. Bonini, M. D'Attanasio and G. Marchesini,"Wilson renormalization group
and gauge invariance", Workshop on QCD: Confinement, Collisions, and
Chaos, American University of Paris, June, 1996
6. M. Bonini, M. D'Attanasio and G. Marchesini, "Perturbative infrared
finiteness of Yang-Mills theory from renormalization group flow", Nucl.
Phys. B444 (1995) 602
7. M. Bonini, M. D'Attanasio and G. Marchesini, "BRS symmetry for Yang-Mills
theory with exact renormalization group", Nucl. Phys. B437 (1995) 163
8. M. Bonini, M. D'Attanasio and G. Marchesini, "BRS symmetry from
renormalization group flow", Phys. Lett. B 346 (1995) 87
Integrable Quantum Field Theory
The main research activity has dealt on non perturbative approaches to two
dimensional modes of Quantum Field Theory and Statistical Mechanics. In
particular a single nonlinear integral equation has been derived which is
capable of describing within a fully unified approach the thermodynamics
and the finite-size effects of quantum spin chains as well as the ground--
state scaling function, in the sense of Perturbed Conformal Field Theories,
of the sine—Gordon model. Moreover a new U(1)--invariant local and
integrable lattice formulation of the massive Thirring model has been
obtained and thoroughly studied. Another significant activity, intermediate
between research and teaching, has been the writing of the book "Istituzioni
di Fisica Teorica" for third year students, in collaboration with Prof. Enrico
Onofri of Parma University. The book covers a wide range of material, from
Classical to Quantum Mechanics. In particular this latter is treated in detail
both in the purely theoretical aspects and in the applicative ones. (Claudio
Destri)
1. C. Destri and H.J. de Vega, "Unified approach to thermodynamic bethe
ansatz an finite size corrections for lattice models and field theories", Nucl.
Phys. B438 (1995) 413.
2. L. Belardinelli, C. Destri and E. Onofri, "A numerical study of the RG
equation for the deformed O(3) nonlinear sigma model", Nucl. Phys. B443
(1995) 607.
3. C. Destri and T. Segalini. "A local and integrable lattice regularization of the
massive Thirring model", Nucl. Phys. B455 (1995) 759.
4. C. Destri, "U(1)--invariant local and integrable lattice formulation of the
massive Thirring model", [Proceeding of the Satellite Meeting of
STATPHYS-19 on Statistical Models, Yang-Baxter Equation and Related
Topics, Nankai University, Aug 8-10, 1995], World Scientific, Singapore, fall
1996.
5. Enrico Onofri e Claudio Destri, ”Istituzioni di Fisica Teorica'', La Nuova
Italia Scientifica, Roma, apr. 1996.
Renormalization problems in the Standard Model
The absence of a symmetric regularization in the Standard Model (due to
the presence of y5 in the electroweak sector) requires some strategy in
order to recover Slavnov-Taylor identities for the vertex functions. This
problem is studied in explicit physical processes (e.g. bÕs +y) and in
connection with various algorithms in field theory: decoupling theorem,
Renormalization Group, Wilson Operator Expansion, etc. ( Ruggero
Ferrari)
1. R. Ferrari, A. Le Yaouanc, L. Oliver and J.C. Raynal, “Gauge invariance
and dimensional regularization with y5 in flavor-changing neutral
processes”, Phys. Rev. D 52, 3036 (1995)
Gauge Theories: non perturbative effects.
The first order formulation for Yang-Mills theories has been studied. In this
formulation the gauge theory appears as a deformation of a topological
theory of BF type. Among other results new non local observables can be
inheredited from the topological theory and an explicit realization of the
algebra of order-disorder operators has been given. (Maurizio Martellini ,
Mauro Zeni)
1. M. Martellini, A. Sagnotti and M. Zeni, “Shock waves and the Vacuum
Structure of Gauge Theories”, eds. N. Brambilla e G.M. Prosperi, World
Scientific 1995
2. F. Fucito, M. Martellini and M. Zeni, “The BF Formalism for QCD and Quark
Confinement”, IFUM 526/FT May 1996
3. F. Fucito, M. Martellini and M. Zeni, “ A new Non Perturbative Approach to
QCD by BF Theory”, Proceedings of the “Second International Sakharov
Conference”, May 1996
4. M. Martellini, and M. Zeni, “The BF Formalism for Yang-Mills Theory and
the Thooft Algebra”, Proceedings of “ Quark Confinement and Hadron
Spectrum 1996”, Como, June 1996
5. F. Fucito, M.Martellini and M. Zeni, “Non Local Observables and
Confinement in BF Formulation of Yang-Mills Theory”, Proceedings of the
“Cargese Nato Summer School”, July 1996
Elementary particles, QCD and Standard model
QCD bound states
The problem of quark confinement and bound states in QCD is considered
from various points of view. Quark-antiquark and three quark potentials
have been obtained in a Wilson context and are currently applied to study
the spectra and the properties of mesons and barions. A confining Bethe-
Salpeter equation has also been derived. Improvements of the entire
formalism and its relations with other approaches are under investigation.
(Giovanni Maria Prosperi, Nora Brambilla)
1. N. Brambilla e G.M. Prosperi (eds.), "Quark Confinement and the Hadron
Spectrum", World Scientific, 1995.
2. N. Brambilla e G.M. Prosperi, "Wilson loop, q-qbar and 3q potentials,
Bethe-Salpeter equation", in "Quark Confinement and the Hadron
Spectrum", N. Brambilla e G.M.Prosperi eds., World Scientific, 1995,
pag. 113.
3. N. Brambilla and G.M.Prosperi, "The Wilson loop qqbar and qqq
potential" in DPF94, ed. S.Seidel, World Scientific 1995, pag. 1718.
4. N. Brambilla e G.M.Prosperi, "Wilson loop approach to qqbar potential",
in "Confinement 95", eds H.Toki et al., World Scientific, 1995, pag.164
5. N. Brambilla e G.M.Prosperi, "Confining Bethe-Salpeter equation in QCD",
in "Confinement 95", eds. H.Toki et al., World Scientific, 1995, pag.164
6. N. Brambilla, G.M. Prosperi e A. Vairo, "Three-body relativistic flux tube
model from Wilson loop approach", Phys. Lett. B362, 113 (1995)
7. N. Brambilla e G.M. Prosperi, "Quark-antiquark Bethe-Salpeter equation
in QCD", in "Non Perturbative Approaches to Quatum Chromodynamics",
D. Diakonov ed., (PNPI 1995), pag. 123
8. N. Brambilla, E. Montaldi e G.M. Prosperi, "Bethe-Salpeter equation in
QCD in a Wilson loop context", Phys. Rev. D54, 3506 (1996)
9. M. Baker, J. Ball, N. Brambilla, G.M. Prosperi e F. Zachariasen,
"Confinement: understanding the relation between the Wilson loop and
Dual Theory of long distance QCD", Phys. Rev. D54, 2829 (1996)
10. E. Montaldi, N. Brambilla, G.M. Prosperi, "Bethe-Salpeter equation in
QCD in a Wilson loop context", Phys. Rev. D 54 (1996), 3506
Power corrections in hard QCD processes and non-perturbative
phenomena
Non-perturbative effects leading to corrections suppressed by a power of
the characteristic energy scale. Relation to renormalons. (Yuri L.
Dokshitzer, Giuseppe Marchesini, Paolo Nason)
1. Y.L. Dokshitzer, G. Marchesini and B.R. Webber, “Dispersive approach to
power-behaved contributions in QCD hard processes, Nuclear Physics B
469 (1996) 93.
2. G. Marchesini, Power corrections in QCD hard processes and IR
renormalons, “ QCD at large orders”, Rheinsberg, May 96, Nucl. Phys. B
(Proc. Suppl.) 516 (1996) 209
3. P. Nason, B.R. Webber, “Non-perturbative corrections to heavy quark
fragmentation in e+ e- annihilation, CERN-TH-96-290, Dec. 1996. 11pp.
4. P. Nason, Michael H. Seymour, “Infrared renormalons and power
suppressed effects in e+ e- jet events. Nucl. Phys. B454:291-312, 1995.
5. Yu. L.Dokshitzer, B.R. Webber, “ Calculation of power corrections to
hadronic events shapes”, Phys. Lett. 352B (1995) 451-455
6. Yu. L. Dokshitzer and N.G. Uraltsev, “Are IR renormalons a good probe for
the strong interaction domain?”, Phys. Lett. 380B (1996) 141-150
Deep inelastic scattering at small x
Hard collisions with incoming hadrons are studied in the phase space
region where angular ordering of emitted QCD radiation has an important
effect on the final state structure. (Giulio Bottazzi, Giuseppe Marchesini,
Gavin Salam, Massimo Scorletti)
1. G. Marchesini, “QCD coherence in the structure function and associated
distributions at small x”, Nucl. Phys. B 445 (1995) 49
2. G. Marchesini, “Coherence at small x”, Nucl. Phys. (proc. Suppl.) 39B,C
(1995) 18
3. G. Marchesini, “Short distance evolution equation at small x, Deep Inelastic
scattering and QCD”, Paris 1995 J-F. Laporte and Y. Sirois Ed.
4. G. Bottazzi, G. Marchesini and M. Scorletti, “Coherence and final states in
DIS at smallx”, “DIS96”, Roma, April 96, to be published.
5. G. Bottazzi, G. Marchesini and M. Scorletti, Final states properties in QCD
branching processes at small x, “QCD at large orders”, Rheinsberg, May
96, Nucl. Phys. B (Proc. Suppl) 516 (1996) 250
Heavy quark production
Soft-gluon resummation is analysed for the production of high-mass
systems in hadronic collisions, with particular relevance for top quark
production. Studies are also made of higher order perturbative contributions
to heavy-quark production in ep collisions. (Yuri L. Dokshitzer, Paolo
Nason, Carlo Oleari)
1. Yu.L. Dokshitzer, V.A. Khoze, S.I. Troyan, “Specific features of heavy quark
production. LPHD approach to heavy particle spectra”, Phys. Rev. D53
(1996) 89-119
2. P. Nason, “Soft gluon resummation in heavy flavor production”,Talk given at
10th Les Rencontres de Physique de la Vallee d’Aoste: Results and
Perspectives in Particle Physics, La Thuile, Italy, 3-9 Mar 1996
3. P.Nason, C.Oleari, “Momentum correlations in Z0 -... b and the
measurement of R(b). Phys.Lett. B387:623-628, 1996.
4. S. Catani, M. L. Mangano, P. Nason, L. Trentadue,”The resummation of soft
gluons in hadronic collisions”, Nucl.Phys. B478:273-310,1996
5. S. Bethke, M. L. Mangano, P. Nason,” QCD in e+ e- collisions at TeV.
Annecy/Assergi/Hamburg 1995, e+ e- collisions at TeV energies, pt. B83-
92.
6. P. Nason, B.R. Webber, D. Ward, D. Lanske, L.A. del Pozo, F. Fabbri, B.
Poli, G. Cowan, C. Padilla, M. Seymour, F. Hautmann, Y.L. Dokshitzer, V.A.
Khoze, “QCD”, HEPPH-9602288, Feb.1996 41pp. To appear in CERN-96-0
7. S. Catani, M.L.Mangano, P. Nason and L. Trentadue, “The top cross-
section in hadronic collisions”, Phis. Lett B378: 329-336, 1996.
8. P. Nason, S. Frixione, G. Ridolfi,” Heavy flavor production”, Physics in
Collision 1995:499-514
9. S. Frixione, P. Nason, G. Ridolfi, “Differential distributions for heavy flavor
production at HERA”, Nucl. Phys. B454:3-24, 1995.
10.S. Frixione, M.L.Mangano, P. Nason, G. Ridolfi, “Top quark distributions in
hadronic collisions”, Phys. Lett. B351: 555-561, 1995.
QCD in a medium
The radiative energy loss in a medium in analyzed in perturbative QCD. A
broadening in the pt spectrum is obteined. (Yuri L. Dokshitzer)
1. R. Baier, Yu.L. Dokshitzer, S. Peigné, D. Schiff, “Induced gluon radiation in
a QCD medium”, Phys. Lett. 345B (1995) 277-286
2. R. Baier, YU.L. Dokshitzer, A.H. Mueller, S. Peigné, D. Shiff, “The Landau-
Pomeranchuk. Migdal effect in QED”, Nucl. Phys. B478 (1996) 577-597;
also in Moriond 1995: Hadronic: 553-558
3. R. Baier, Yu.L. Dokshitzer, A.H. Mueller, S. Peigné, D. Schiff, “Radiative
energy loss of high-energy quarks and gluons in a finite volume quark-
gluon plasma”, hep-ph/9607355, to appear in Nucl.Phys. B
4. R. Baier, Yu.L. Dokshitzer, A.H. Mueller, S. Peigné, D. Schiff, “Radiative
energy loss and pt broadning of high-energy partons in nuclei”, hep-
ph/9608322, to appear in Nucl. Phys. B
Perturbative unitarity in QCD
A feature new to future high-energy hadron colliders is that individual
hadron-hadron collisions will involve several parton-parton interactions. A
full study is difficult because it involves non- perturbative QCD, but an
understanding of the perturbative component of the problem can be
obtained by studing the collisions of heavy hadrons, which are simpler,
yielding results for the behaviuor of the total cross-section and final state
properties at high-energies. (Gavin Salam)
1. G.P. Salam, “Mutiplicity distribution of colour dipoles at small x”, Nuclear
Physics B449, p.589-604 (1995)
2. G.P. Salam, “Studies of unitarity at small x using the dipole formulation”,
Nuclear Physics B461, p. 512-538 (1996)
3. G.P. Salam, “OEDIPUS: Onium Evolution, Dipole Interaction and
Perturbative Unitarisation Simulation”, Cavendish preprint HEP-95/07, hep-
ph/9601220, submitted to Computer Physics Communications.
4. A.H. Mueller and G.P. Salam, “Large multiplicity fluctuations and saturation
effects in onium collisions”, Nuclear Physics B475, p.293-320 (1996)
5. R. Peschanski and G.P. Salam, “The QCD dipole picture of small-x
physics”, in “Hamburg 1995/96, Future physics at HERA”, p.110-115.
Statistical field theory and Statistical mechanics
High temperature expantions at large order
Significant extensions of the high temperature expansions for the general O(N)
invariant lattice scalar field theory have been obtained in any spatial
dimension, by the Schwinger-Dyson equation method or by the linked cluster
method. This gives accurate tests of the validity of the universality hypothesis
on which the renormalization group approach to critical phenomena is based
and also of the approximation procedures required to produce numerical
estimates of universal quantities by field theoretic methods. (Paolo Butera,
Marcattilio Comi)
1. P. Butera e M. Comi , "Extended high temperature series for the N-vector
spin models on three-dimentional bipartite lattices", Phys. Rev B52, 6185
(1995)
2. P. Butera e M. Comi, "Perturbative renormalization group, exact results
and high temperature series for the N-vector spin models on the square
lattice." Phys. Rev. B54 12486 (1996)
3. P. Butera e M. Comi, "The 2n-point renormalized coupling constants in
the 3d Ising Model: estimates by high temperature series to order
beta^17" IFUM 545/FT preprint Novembre 1996, inviato a Phys. Rev. E.
4. P. Butera e M. Comi, "N-vector spin models on the sc and the bcc lattices:
a study of the critical behavior of the susceptibility and of the correlation
length by high temperature series extended to order beta^21"
IFUM 548 /FT preprint Dicembre 1996
Computational physics and Lattice gauge theory
APE parallel processor is used for Lattice gauge theory calculations of
perturbation expansions and infrared renormalons. Non convergence of
the perturbative expansion is studied. APEmille project (Giuseppe
Marchesini)
1. F. Di Renzo, G. Marchesini and E. Onofri, "Renormalons from eight loop
expansion of the gluon condensate in lattice gauge theory", Nuclear
Physics B 457 (1995) 202
2. F. Di Renzo, G. Marchesini, P. Marenzoni and E. Onofri," Weak Coupling
Perturbation Theory by Langevin Dynamics: Fourth Loop and Beyond",
Nuclear Physics B (Proc. Suppl. ) 42 (1995) 867
3. C. R. Allton, S. Antonelli, M. Bellacci, N. Cabibbo, M. Crisafulli, G. Curci,
V. Lubicz, G. Marchesini, G. Martinelli, E. Onofri, G. Parisi, R. Petronzio,
F. Rapuano, J.J. Ruiz-Lorenzo, R. Sarno, R. Tripaccione, A. Vladikas, F.
Zuliani, PHYSICS PROJECTS ON APE 1000, INFN document (Roma,
Milano, Parma, Pisa, Boston, March 6, 1995)
Quantum Hall Effect
The many-body problem of Quantum Hall Effect is studied in some of its
aspects: Coulomb interaction among the electrons, Fractional Quantum Hall
Effect in presence of external periodic potential, Laughlin Ansatz, Wannier
functions, etc. (R. Ferrari, N. Datta and R. Morf)
1. R. Ferrari, “Wannier functions and Fractional Quantum Hall Effect”, Int. J.
Mod. Phys. B 9, 3333 (1995).
2. N. Datta, R. Morf. And R. Ferrari, “Edge of the Laughlin droplet”, Phys. Rev.
B 53, 10906 (1996)
Statistical mechanics and field theory on graphs
Universal properties in critical behaviour and phase transitions on
geometrically disordered structures, fractal and graphs, are studied. The
extension of the concept of dimensionality to non translationally invariant
networks is considered.
1. R. Burioni and D. Cassi, “Spectral dimention of fractal trees”, Phys. Rew.
E, 51, 2865 (1995)
2. R. Burioni and D. Cassi, Comment on “Critical dimensionalities of phase
transitions on fractals”, Phys. Rew. E, 51, 3782 (1995)
3. R. Burioni and D. Cassi, “Universal properties of spectral dimension”, Phys.
Rev. Lett., 76 1091 (1996)
4. R. Burioni, D. Cassi and S. Regina, “ Dynamical dimention splitting on non
decimable fractals”, to appear on Proceeding of the III Conference on
Renormalization Group, Dubna (World Scientific, 1996)
5. R. Burioni, D. Cassi and S. Regina, “Dynamical dimention splitting on
fractals: structure with different diffusive and vibrational spectral dimention”,
Mod. Phys. Lett. B 10 1059 (1996)
Disordered system and critical dynamics
Disered systems and localization, in particular electron motion in random
magnetic field. Scaling analysis in systems far from equilibrium (e.g. transient
behaviour in phase-separating systems. Ward identities for stochastic growth
of a surface are dirived from symmetry principles of the differential equation.
Glassy dynamics for disordered spin models are studied by analyzing the
phase space structure in asympotic out of equilibrium systems. (Vincenzo
Benza, Raffaella Burioni)
1. V.Benza, B. Cardinetti and L. Molinari, ”Coulomb-gas approach to quantum
motion in random magnetic fields”, Phys. Rev. B52, R5499 (1995)
2. V. Benza and M.P. Riva, “Coarsening dynamics in crosslinked polymers”, to
be published on Journal de Physique II (france) Feb. 1997
3. R. Burioni, “ Symmetry properties in surface growth models”, Phys. Rew. E
51, 5246 (1995)
4. A. Barrat, R. Burioni and M. Mézard, “Dynamics within metastable states in
a mean-field spin glass”, J. Phys. A 29, L 81 (1996)
5. A. Barrat, R. Burioni and M. Mézard, “ Aging classification in glassy
dynamics”, J. Phys. A 29, 1311 (1996)
Matrix models
Matrix models are an important tool for providing analytical solutions to
problems of 2D statistical mechanics on random lattices, and for a
nonperturbative approach to quantum gravity and string theory. They also
exhibit statistical spectral properties that are typical of chaotic and complex
systems, or transport models with disorder. ( Luca Molinari, Emilio Montaldi )
1. B. Cardinetti, V.G. Benza and L. Molinari, "Coulomb-gas approach to
quantum motion in random magnetic fields", Phys. Rev. B52 (1995)
R5499-R5501
2. I. Guarneri, K. Zyczkowski, J. Zakrzewski, L. Molinari and G. Casati,"
Parametric spectral correlations of disordered systems in the Fourier
domain", Phys. Rev. E52 (1995)
3. F.M. Izrailev, L. Molinari and K. Zyczkowski, "Periodic and non periodic
band random matrices: structure of eigenstates", J. Physique I France
6 (1996) 455-468
4. G. M. Cicuta, L. Molinari, E. Montaldi and S. Stramaglia," A Matrix model
for Random Surfaces with Dynamical Holes", J. Phys. A29 (1996)
3769-3785
5. E. Montaldi, G.M. Cicuta, L. Molinari, S. Stramaglia, "A Matrix Model for
Random Surfaces with Dynamical Holes", J. Phys. A 29 (1996), 3769
6. L. Molinari, "Tranfer Matrices and Tridiagonal-Block Hamiltonians with
periodic and scattering boundary conditions", J. Phys. A., in press
Classical perturbation theory
The research work is related to classical perturbation theory, with particular
attention to KAM and Nekhoroshev's theory. The main results concren on the
one hand the relation between these two methods, leading to the discovery of
phenomena of superexponential stability, and, on the other hand, the
application of Nekhoroshev's theory to physical system with the aim of
obtaining realistic estimates of the thresholds. (Antonio Giorgilli)
1. A.Giorgilli, "Quantitative methods in classical perturbation theory",
proceedings of the Nato ASI school "From Newton to chaos: modern
techniques for understanding and coping with chaos in N-body dynamical
systems", A.E. Roy and B.D. Steves eds., Plenum Press, New York (1995)
2. M. Andreolli, D. Bambusi and A. Giorgilli, "On a weakened form of the
averaging principle in multifrequency systems", Nonlinearity, 8, 283-293
(1995)
3. A. Morbidelli and A. Giorgilli, "Superexponential stability of KAM tori", J.
Stat. Phys. 78, 1607-1617 (1995)
4. A. Morbidelli and A. Giorgilli, "On a connection between KAM and
Nekoroshev's theorem", Physica D, 86, 514-516 (1995)
5. A. Giorgilli and U. Locatelli, "Kolmogorov theorem and classical perturbation
theory", preprint, ZAMP, in press
6. A. Giorgilli and A. Morbidelli, "Invariant KAM tori and global stability for
Hamiltonian systems",ZAMP, in press
7. A. Giorgilli and U. Locatelli, "A classical self-contained proof of
Kolmogorov's theorem on invariant tori, to be published on the proceedings
of the Nato ASI school in Sagaro" (1995)
8. A. Morbidelli and A. Giorgilli, "On the role of high order resonances in
normal forms and in separatrix splitting", Phys. D. (1996)
9. A. Giorgilli and C. Skokos, "On the stability of the Trojan asteroids", Astron
and Astroph., in press
Geometry of classical field and Q. M.
Local symmetry in classical field theory
Applications of global analysis methods in classical field theory with local
symmetries. Geometrical structures in state space of quantum systems:
relation between their canonical Kaehler structure and the symplectic structure
of their classical limit (in state spaces arising in the quantization of classical
systems, in particular in the Weyl quantization). Bohm-Ahoronov effect (Renzo
Cirelli, Maria Cristina Abbati, Alessandro Manià, Fausto Valz-Gris)
1. R. Cirelli, A. Mania', L. Pizzocchero, "A functional Representation for non-
commutative C* -algebras", Reviews in Mathematical Physics, Vol. 6, No 5
(1994) 675-697
2. M.C. Abbati, R. Cirelli, S. De Santis, E. Ruffini, "The Second Noeth
Theorem in the Formalism of Jet-Bundles: Symmetries and Degeneration",
to be published in Jour. Geom. Phys.
3. C. Magni, F. Valz-Gris, “Can elementary Quantum Mechanics explain the
Bohrm-Aharamov effect”, J.M.P. Vol.36, n.1, (1995) 177
Quantum Mechanics, Wave Equations in Cosmology
A formulation of the causality principle in special relativity is studied in terms of
the properties of the related Minkowski Causal Logic. Quantum Mechanics and
Stochastic Electrodynamics with spin are shown to provide different previsions
in case of wave packets through a slit.
The Dirac equation and the massless field equations for arbitrary spin are
integrated in the Robertson-Walker space-time. The source free Maxwell
equations are derived by interpreting the massless spin 1 field equation in an
arbitrary curved space-time. ( Antonio Zecca )
1. A. Zecca, "Non conservation of the Net Current of Dirac Particles
in Tolman-Bondi and Robertson-Walker Geometry ", Int. Jour.
Theor. Phys., 34, 1083 (1995)
2. A. Zecca, "The Dirac Equation in the Robertson-Walker Space-Time",
Jour. Math. Phys., 37, 874 (1996)
3. A. Zecca, "Separation of the Massless Spin-1 Equation in Robertson-
Walker Space-Time", Int. Jour. Theor. Phys., 35, 383 (1996)
4. A. Zecca, " Separation of the Massless Field Equations for
Arbitrary Spin in the Robertson-Walker Space-Time", Jour. Math.
Phys. 37, 3539 (1996)
5. A. Zecca, "Electromagnetic Interpretation of the Massless Spin 1
Field Equation in Curved Space-Time", Int. Jour. Theor. Phys. 35,
2647 (1996)
6. A. Zecca, "Discriminating Between QM and SED with Spin", in
"Physical Interpretations of Relativity Theory (PIRT)", ed.
by M.C. Duffy, London: 6-9 September 1996
7. A. Zecca, "Non Standard Aspects of Minkowski Causal Logic",
Foundations of Physics Letters, 9, 295 (1996)
8. A. Zecca, "Electromagnetic Interpretation of the Massless Spin 1
Field Equation in Curved Space-Time", Int. Journ. of Theoretical
Physics, 35, 2647 (1996)
9. A. Zecca, G. Cavalleri, "Gassian Wave Packets Passing Through a
Slit: a Comparison Between the Predictions of the Schrodinger QM
and of Stochastic Electrodynamics with Spin", Il Nuovo Cimento
B112, 1 (1996)
10. A. Zecca, "Scalar Field Equation in the Robertson-Walker
Space-Time", Int. Journ. of Theoretical Physics, 36, 1387 (1997)
11. A. Zecca, "Well Barrier Potential for the Massless Spin 1
Field Equation in the Robertson-Walker Space-Time", Il Nuovo
Cimento B, In Press
On the Phase Velocity of the Quantal Waves
As a consequence of the theory of the characteristics of the partial differential
equations the law wave front of a quantal wave moving in electrostatic and
magnetostatic fields is formally identical with the corresponding law for zero
magnetic fields. And phase velocity, wavelength, and refractive index are
formally identical both in the presence and in the absence of magnetic fields.
Angelo Loinger)
1. A. Loinger, “On the Phase Velocity of the Quantal Waves”, Nuovo Cimento,
Vol. 108A, P.115 (1995)
Thermal Effects in quantum gravity
The thermal properties of a class of manifolds with bifurcate horizon has been
studied and the quantized structure of admissible temperatures has been
formally given in terms of odd multiples of the fundamental one. (Mauro Zeni)
1. M. Bertola, V. Gorini and M. Zeni, “Quantized Temperature Spectra in
Curved Spacetime”, IFUM 513/FT August 1995
Beam Physics
Theoretical and numerical analysis of the atomic equivalent of the free-
electron-laser (Collective Atomic Recoil Laser). Analysis of the generation of
short-wovelength radiation in a free-electron-laser starting from noise. Plasma-
free-electron-laser: study of the emission of radiation and of the acceleration of
electrons. ( Rodolfo Bonifacio, Cesare Maroli, Vittoria Petrillo)
1. V. Petrillo, A. Serbeto, C. Maroli, R. Parrella, R. Bonifacio, "Plasma-beam
interaction in a wiggler ", Physical Review E 51, 6293 (1995)
2. V. Petrillo, C. Maroli, R. Bonifacio, A. Serbeto, "High-gradient acceleration
of electrons in a plasma loaded wiggler", Physical Review E 52,4338 (1995)
3. R. Bonifacio, L. De Salvo, "Collettive resonant Compton scattering by two-
level particles", Optics Comminications 115, 505-510 (1995)
4. R. Bonifacio, L. De Salvo, "Analytical theory of the collective atomic recoil
laser in the FEL limit", Applied. Physics B60, S233-S239 (1995)
5. L. De Salvo, R. Bonifacio, W. Barletta, "Transverse laser cooling of two-
level particle beams", Optics Communications 116, 374-376 (1995)
6. L. De Salvo, R. Cannerozzi, R. Bonifacio, E.J. D'Angelo, L.M. Narducci,
"Collective-variables description of the atomic-recoil laser", Physical
Review A 52, 2343 (1995)
Electromagnetic interaction in condensed matter
systems
Coherent electromagnetic dynamics in liquids. Production of membranes
through the dispersive interaction in liquid water. Coherent dynamics inside
nuclear matter in the neutron stars. ( Emilio Del Giudice )
1. R. Arani, I. Bono, E. Del Giudice, G. Preparata, "QED coherence and the
thermodynamics of water", Int. Jour. Mod. Phys. B, 9 (1995) 1325
2. E. Del Giudice, G. Preparata, "Coherent dynamics in water as a possible
mechanism membrane formation", to be published in Jour. of Biol. Phys.
(1995) 412
3. E. Del Giudice, C. Giraldi, G.P. Mangano, R. Mele, G. Miele, G. Preparata,
"Neutron stars and the coherent nuclear interaction", Int. Jour. Mod. Phys.
D (1995) 1202
Applied Mathematics
Dynamics of fluids and application of viariational methods
An inverse problem in Geophysics is studied that is connected with the
dynamics of fluids. The problem is that of evaluating the transmissivity (the
parameter that regulates the flow of a fluid in a porous medium ) uniquely,
when the value of the hydraulic potential (the Gibbs potential added to the
gravitational potential) of the fluid is known. The evaluation is to be
implemented both in the continuous and in the discrete case. (Guido
Parravicini, Fausto Valz Gris)
1. G. Parravicini, M. Giudici, G. Morossi,G. Ponzini, "Minimal a priori
assignment in a direct method for determining phenomenological
coefficients uniquely", to be published in Inverse Problems
2. M. Giudici, G. Morossi, G. Parravicini, G. Ponzini, "A new method for the
determination of distributed transmissivities", to be published in Water
resources Research
3. M. Pinto, F. Valz Gris, M. Vezzoli, “A variational approach to evaluate
interdiod capacities in Silicon Pixel detectors”, to appear in Nucl.. Inst. And
Methods in Physics Research Sez.A (May 1997)
Mathematical Analysis and Special Functions
The classical hypergeometric identities of Cayley and Orr are reexamined.
Various other identities of this type are detained. (Nora Brambilla, Emilio
Montaldi)
1. E. Montaldi, H.M. Srivastava," A Note on the Hypergeometric Identities of
Cayley and Orr", Math. Balk. 9 (1995), 51
2. N. Brambilla e A. Vairo, "Perturbative evaluation of the eigenvalues of the
Herbst equation", Phys. Lett. B359, 133 (1995)
3. N. Brambilla and E. Montaldi, "Remarks on some series considered by
Ramanujan", Mathematica Balkanica, 10 (1996)
4. E. Montaldi, H.M. Srivastava, G. Zucchelli, "Hypergeometric Identities of
Caley and Orr Types: Some Alternative Approaches", Appl. Math. and
Comp. 76 (1996), 1
Sergio Caracciolo (Universita' di Lecce), "Nuove classi di universalita' per i
modelli sigma" - 21 gennaio 1994
Michelangelo Mangano (Scuola Normale Superiore di Pisa), "Produzione di
Quark pesanti in collisioni adroniche" - 28 gennaio 1994
Mikhael Cherkov (Weizmann Institute), "Turbolenza completamente
sviluppata", - 11.18.25.27 gennaio 1994, 1.2.3.4.7.8 febbraio 1994
Paolo Nason (CERN-Ginevra), "Test di QCD e misure di alpha a LEP", - 10
febbraio 1994
W. Barletta (Lawrence Berkley Laboratory), "Prospects for a high energy muon
collider", - 17 febbraio 1994
W. Barletta (Lawrence Berkley Laboratory), "The FEL as buncher for high
energy colliders", - 21 febbraio 1994
Paolo Maranner (Universita' di Parma), "Campi di gauge e potenziali indotti
dalla geometria nella meccanica quantistica dei sistemi vincolati", - 23
febbraio 1994
Carlo di Castro (Universita' La Sapienza di Roma), "Transizione dimensionale
tra liquido di Luttinger e liquido di Fermi", - 10 marzo 1994
Antonio Masiero (INFN - Padova), "Implicazioni del problema della materia
oscura per la fisica delle particelle", - 17 marzo 1994
Giuseppe Mussardo (Sissa - Trieste), "Correlation functions in integrable
quantum field theories", - 18 marzo 1994
C.P. Enz (Universita' di Ginevra), "A Form of Superconductivity Theory Joining
Weak and Strong Coupling", - 18 marzo 1994
Roberto Corsini (CERN), "Il FEL come buncher per CLIC", - 28 marzo 1994
Stefano Catani (INFN - Firenze), "QCD e risultati di HERA su funzioni di
struttura a piccolo X", - 8 aprile 1994
Antonio Serbeto (Universita' Fluminense di Rio de Janeiro), "Non-Linear
amplification of inverse bremsstrahlung electron acceleration", - 26 aprile
1994
Ruggero Ferrari (Universita' di Trento), "Confronto tra rinormalizzazione
dimensionale naive e di 't Hooft-Veltman: esempio di processi dove la
corrente debole e' neutra ma cambia sapore", - 29 aprile 1994
Antonio Bassetto (Universita' di Padova), "Loop di Wilson di tipo luce e
invarianza di gauge in 1+3 e 1+1 dimensioni", - 19 maggio 1994
Enrico Celeghini (Universita' di Firenze), "Operatori quantistici di creazione e
distruzione e statistica delle particelle", - 2 giugno 1994
Alberto Lerda (Universita' di Salerno), "Teorie di gauge per sistemi di elettroni
fortemente correlati", - 3 giugno 1994
Andrea Cappelli (INFN - Firenze), "Classificazione degli stati dell'effetto Hall
quantistico mediante la simmetria W-infinito", - 9 giugno 1994
Antti Kupiainen (Helsinki), "Renormalizing non linear partial differential
equations", - 1 luglio 194
Saverio Pascazio (Universita' di Bari), "Effetto Zenone quantistico", - 5 luglio
1994
A. Holevo (Steklov Institute di Mosca), "Excessive maps, arrival times, and
perturbations of dynamical semigroups", - 25 luglio 1994
Viktor Belinitcher (Universita' di Novosibirsk Russia), "Kinetic approach to the
ploblem of developed hydrodynamic turbolence" and "Scaling solution of
the passive scolar problem in turbolence", - 30 settembre 1994
Roland Kirschner (Universita' di LIPSIA), "Small x-structure functions", - 10
ottobre 1994
Roland Kirschner (Universita' di LIPSIA), "QCD Regge asymptation and
integrable models", - 11 ottobre 1994
Roland Kirschner (Universita' di LIPSIA); "Reggeon interaction in QCD"; - 12
ottobre 1994
Andrea Pasquinucci (Niels Bohr Institute), "On the computation of one loop
amplitudes with external fermions in 4D heterotic superstrings", - 20 ottobre
1994
Ugo Moschella (Service de Physique Theorique Saclay), " Teoria quantistica
dei campi sullo spazio-tempo di De Sitter", - 4 novembre 1994
A. Sartori, (IRST Trento), G. Tecchiolli (INFN gruppo collegato di Trento),
"TOTEM: un chip ad elevato parallelismo per applicazioni di triggering", 4
novembre 1994
Ignazio Ciufolini (Istituto di Fisica dello Spazio Interplanetario del CNR
Frascati), "Gravitomagnetismo e sua misura", - 7 novembre 1994
Prospero Simonetti (Sissa - Trieste), "Funzioni di correlazione di modelli
integrabili", - 10 novembre 1994
Georges Grunberg (Ecole Polytechnique Parigi), "A suggestion to remove the
Landau ghost", - 17 novembre 1994
Martin Beneke (Ann Arbor University), "ARGE-order Perturbation theory in
Renormalizable Theories", - 21 novembre 1994
Bodo Lampe (Max Planck Insitute), "The TOP Quark and QCD", - 25 novembre
1994
Giuseppe Nardulli (Universita' di Bari), "Applicazioni delle reti neutrali alla
fisica delle alte energie ", - 30 novembre 1994
24