Martino Lovisetto
Optical Analogue Of SelfGravitating Systems.
Rel. Alessandro Pelizzola. Politecnico di Torino, Corso di laurea magistrale in Physics Of Complex Systems (Fisica Dei Sistemi Complessi), 2018

PDF (Tesi_di_laurea)
 Tesi
Licenza: Creative Commons Attribution Noncommercial No Derivatives. Download (2MB)  Preview 
Abstract: 
Many interactions in nature are long range. As long range interactions, we refer to those in which parts of the system far away from each other interact considerably. An historical example of such systems are stars inside a galaxy or globular clusters. Typically, in such a system, a star is subjected to a force dominated by the ensemble of the other stars (long range) rather than, for example, the neighboring ones (short range). As a consequence, one expects a very different behavior (and often counterintuitive) compared to what happens in the shortrange interacting regime usually encountered in statistical physics textbooks. For example, in the thermodynamic equilibrium, there is nonequivalence of ensembles or a possible apparition of negative specific heat in the microcanonical ensemble. The macroscopic dynamics is also very different: starting from arbitrary initial conditions, the system forms rapidly a quasistationary state (like a galaxy) and then relaxes towards thermodynamic equilibrium. Recently, it has been observed that a laser beam propagating through a nonlinear, nonlocal medium presents a behavior very similar to the formation of a quasistationary state of selfgravitating bosons in the nonrelativistic regime, which is a serious candidate for dark matter in the halos of galaxies. The purpose of this internship, is studying theoretically and numerically such an optical analogue of a selfgravitating system. The targeted objectives are:  Full description of the analogy between selfgravitating systems and nonlinear optical propagation, together with a variational approach in order to derive an analytical solution of the equation.  Study the evolution of the system for various initial conditions by writing a code to solve the SchroedingerNewton equation. Comparisons between theory and simulations oriented to the realisation of the optimal experimental procedure in the optical framework. 

Relators:  Alessandro Pelizzola 
Academic year:  2017/18 
Publication type:  Electronic 
Number of Pages:  64 
Subjects:  
Corso di laurea:  Corso di laurea magistrale in Physics Of Complex Systems (Fisica Dei Sistemi Complessi) 
Classe di laurea:  New organization > Master science > LM44  MATHEMATICAL MODELLING FOR ENGINEERING 
Ente in cotutela:  Laboratoire de Mathematiques et Interactions J. A. Dieudonné (FRANCIA) 
Aziende collaboratrici:  UNSPECIFIED 
URI:  http://webthesis.biblio.polito.it/id/eprint/8033 
Modify record (reserved for operators) 