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Seminario Matematico e Fisico di Milano
Piazza Leonardo da Vinci, 32 - 20133 Milano
Direttore: Paolo Stellari
      
Vice Direttore: Gabriele Grillo
      
Segretario: Daniele Cassani

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Gisbert Wuestholz, Eidgenössische Technische Hochschule (Zurigo, Svizzera)
Modern transcendental methods in Diophantine Geometry
Domenica 21 Novembre 2004, ore 17:00
Dipartimento di Matematica - Università degli Studi di Milano - Via Saldini 50 - Milano - Sala di Rappresentanza
 
Dennis Weaire, Trinity College (Dublino, Irlanda)
The many facets of foam
Venerdì 01 Ottobre 2004, ore 15:00
Dipartimento di Matematica - Politecnico di Milano - Via Bonardi 9 - Milano - Aula Consiglio (VII piano)
Abstract
 
José C. Geromel, UNICAMP (Campinas, Brasile)
H2 optimal robust filtering
Mercoledì 07 Luglio 2004, ore 17:00
Dipartimento di Matematica - Università degli Studi di Milano - Via Saldini 50 - Milano - Sala di Rappresentanza
Abstract
 
Alexander N. Sharkovsky, National Academy of Sciences (Kiev, Ucraina)
Ideal turbulence: definition and models
Lunedì 05 Luglio 2004, ore 17:00
Dipartimento di Matematica - Università degli Studi di Milano - Via Saldini 50 - Milano - Sala di Rappresentanza
 
Shige Peng, Shandong University, Jinan (Cina)
Continuous Time Risk Measures and Evaluations by BSDE
Lunedì 14 Giugno 2004, ore 17:00
Dipartimento di Matematica - Università degli Studi di Milano - Via Saldini 50 - Milano - Sala di Rappresentanza
 
Wu-Yi Hsiang, Hong Kong University of Science and Technology (Hong Kong, Cina)
Three body problems in quantum mechanics
Mercoledì 26 Maggio 2004, ore 17:00
Dipartimento di Matematica - Università degli Studi di Milano - Via Saldini 50 - Milano - Sala di Rappresentanza
Abstract
In this talk, I shall describe the geometric approach to solve the Schrödinger equation for various physically meaningful three body systems such as He, H2+, H-, three bosons in R2 with d-function potential etc. The configuration space of the three body system in R3(resp. R2) (with center of gravity fixed at the origin) is an R6 (resp. R4) equipped with an SO(3) (resp. SO(2)) symmetric kinematic metric, while the potential function U is also SO(3) (resp. SO(2)) invariant. The first step is to fully utilize the SO(3) (resp. SO(2)) symmetry to reduce the Schrödinger equation to an equation solely defined at the level of the orbit space (i.e. R6/SO(3) (resp. R4/SO(2))) equipped with the orbital distance metric. One needs to make effective use of both group representation theory and equivariant differential geometry to achieve such a reduction. The orbit space of a three body system in R3 (resp. R2) equipped with the orbital distance metric is always isometric to the Riemannian cone over S2+ (1/2) (resp. S2(1/2))), namely the Euclidean hemisphere (resp. sphere) of radius 1/2. This remarkable fact (i.e. sphericality) enables us to bring in the spherical harmonics and their generalizations (namely, Jacobi polynomials and monopole harmonics) to greatly simplify the analysis of the angular part of the reduced equation. I will use the simpler case of the boson system to illustrate this step which enables us to further reduce the Schrödinger equation to an ODE solely in the radial direction. Such an ODE can be thoroughly analyzed and I will discuss the physical significance of these solutions so obtained for the three boson system. Bibliography Wu-Yi Hsiang. Kinematic geometry of mass-triangles and reduction of Schr¨odinger’s equation of three-body systems to partial differential equations solely defined on triangular parameters. Proc. Nat. Acad. Sci. U.S.A., 94(17):8936–8938, 1997. Wu-Yi Hsiang. On the kinematic geometry of many body systems. Chinese Ann. Math. Ser. B, 20(1):11–28, 1999. A Chinese summary appears in Chinese Ann. Math. Ser. A 20 (1999), no. 1, 141.