Browsing SISSA Preprints by Title

Now showing items 434-453 of 479

Theoretical Prospects of Neutrinoless Double Beta Decay

Petcov, Serguey T. (2005)

The compelling experimental evidences for oscillations of solar and atmospheric neutrinos imply the existence of 3-neutrino mixing in vacuum. We briefly review the phenomenology of 3-v mixing, and the current data on the ...
Thin-walled beams with a cross-section of arbitrary geometry: derivation of linear theories starting from 3D nonlinear elasticity

Davoli, Elisa (SISSA, 2011-06-30)

The subject of this paper is the rigorous derivation of lower dimensional models for a nonlinearly elastic thin-walled beam whose cross-section is given by a thin tubular neighbourhood of a smooth curve. Denoting by h and ...
Time dependent loss of derivatives for hyperbolic operators with non-regular coefficients

Colombini, Ferruccio; Del Santo, Daniele; Fanelli, Francesco; Metivier, Guy (2013-02-04)

In this paper we will study the Cauchy problem for strictly hyperbolic operators with low regularity coe fficients in any space dimension N ≥ 1. We will suppose the coe fficients to be log-Zygmund continuous in time and ...
Time Minimal Trajectories for a Spin 1/2 Particle in a Magnetic field

Boscain, Ugo; Mason, Paolo (2005)

In this paper we consider the minimum time population transfer problem for the z-component of the spin of a (spin 1/2) particle driven by a magnetic field, controlled along the x axis, with bounded amplitude. On the Bloch ...
Time minimal trajectories for two-level quantum systems with drift

Boscain, Ugo; Mason, Paolo (2005-06-20)

On a two-level quantum system driven by an external field, we consider the population transfer problem from the first to the second level, minimizing the time of transfer, with bounded field amplitude. On the Bloch sphere ...
Time quasi-periodic gravity water waves in finite depth

Baldi, Pietro; Berti, Massimiliano; Haus, Emanuele; Montalto, Riccardo (2017)

We prove the existence and the linear stability of Cantor families of small amplitude time quasi-periodic standing water wave solutions - namely periodic and even in the space variable x - of a bi-dimensional ocean with ...
Time-dependent systems of generalized Young measures

Dal Maso, Gianni; DeSimone, Antonio; Mora, Maria Giovanna; Morini, Massimiliano (2005)

In this paper some new tools for the study of evolution problems in the framework of Young measures are introduced. A suitable notion of time-dependent system of generalized Young measures is defined, which allows to extend ...
Time-localized projectors in string field theory with e-field

Maccaferri, Carlo; Scherer Santos, Ricardo Jose; Tolla, Driba Demissie (2005-06-20)

We extend the analysis of hep-th/0409063 to the case of a constant electric field turned on the worldvolume and on a transverse direction of a D-brane. We show that time localization is still obtained by inverting the ...
Tools for the Solution of PDEs Defined on Curved Manifolds with deal.II

DeSimone, Antonio; Heltai, Luca; Manigrasso, Cataldo (2009-07-30)

The deal.II finite element library was originally designed to solve partial differential equations defined on one, two or three space dimensions, mostly via the Finite Element Method. In its versions prior to version 6.2, ...
Topics in String Field Theory

Bonora, Loriano; Maccaferri, Carlo; Mamone, Davide; Salizzoni, Mario (SISSA, 2003)

This review of bosonic string field theory is concentrated on two main subjects. In the first part we revisit the construction of the three string vertex and rederive the relevant Neumann coefficients both for the matter ...
Topological strings live on attractive manifolds

Evslin, Jarah; Minasian, Ruben (2008-04-14)

We add to the mounting evidence that the topological B model's normalized holomorphic three-form has integral periods by demonstrating that otherwise the B2-brane partition function is ill-defined. The resulting Calabi-Yau ...
Topological vector symmetry, topological gauge fixing of BRSTQFT and construction of maximal supersymmetry

Baulieu, Laurent; Bossard, Guillaume; Tanzini, Alessandro (2005)

The scalar and vector topological Yang-Mills symmetries determine a closed and consistent sector of Yang-Mills supersymmetry. We provide a geometrical construction of these symmetries, based on a horizontality condition ...
Towards open-closed string duality: Closed Strings as Open String Fields

Bonora, Loriano; Bouatta, N.; Maccaferri, Carlo (2006-10-04)

We establish a translation dictionary between open and closed strings, starting from open string field theory. Under this correspondence, (off-shell) level-matched closed string states are represented by star algebra ...
Towards the Classification of Exactly Solvable Feynman Path Integrals: $δ$-Function Perturbations and Boundary-Problems as Miscellaneous Solvable Models

Grosche, Christian (SISSA, 1993-08-17)

In this contribution I present further results on steps towards a Table of Feynman Path Integrals. Whereas the usual path integral solutions of the harmonic oscillator (Gaussian path integrals), of the radial harmonic ...
Translation and adaptation of Birman's paper "On the theory of self-adjoint extensions of positive definite operators" (1956)

Khotyakov, Mikhail; Michelangeli, Alessandro (SISSA, 2015)

This is an accurate translation from Russian and adaptation to the modern mathematical jargon of a classical paper by M. Sh. Birman published in 1956, which is still today central in the theory of self-adjoint extensions ...
Transmission conditions obtained by homogenisation

Dal Maso, Gianni; Franzina, Giovanni; Zucco, Davide (2018-03)

We study the asymptotic behaviour of solutions to variational problems in perforated domains with Neumann boundary conditions. We consider perforations that in the limit concentrate on a smooth manifold. We characterise ...
Truncation and convergence issues for bounded linear inverse problems in Hilbert space

Caruso, Noe; Michelangeli, Alessandro; Novati, Paolo (SISSA, 2018)

We present a general discussion of the main features and issues that (bounded) inverse linear problems in Hilbert space exhibit when the dimension of the space is infinite. This includes the set-up of a consistent ...
Twisted Covariance vs Weyl Quantisation

Piacitelli, Gherardo (2009-01-22)

In this letter we wish to clarify in which sense the tensor nature of the commutation relations [x^mu,x^nu]=i theta ^{mu nu} underlying Minkowski spacetime quantisation cannot be suppressed even in the twisted approach to ...
Twisted noncommutative equivariant

Cirio, Lucio (2007-08-09)

We propose Weil and Cartan models for the equivariant cohomology of covariant actions on toric deformation manifolds. The construction is based on the noncommutative Weil algebra of Alekseev and Meinrenken; we show that ...
Two-dimensional Schrödinger operators with point interactions: Threshold expansions, zero modes and Lp-boundedness of wave operators

Cornean, Horia D.; Michelangeli, Alessandro; Yajima, Kenji (SISSA, 2019-10-10)

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