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| Author(s): |
Kellen Manoela Siqueira
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Física Gleb Wataghin |
| Defense date: | 2017-05-10 |
| Examining board members: |
Marcus Aloizio Martinez de Aguiar;
Marcus Vinicius Segantini Bonança;
Maurice de Koning;
Marcelo Amorim Marchiori;
Ibere Luiz Caldas
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| Advisor: | Marcus Aloizio Martinez de Aguiar |
| Abstract | |
We studied the impact of internal degrees of freedom in the dynamics of the center of mass in three different settings: The first corresponds to a composite particle in a one dimensional billiard in the context of Fermi Acceleration (FA). When one of the billiard's walls is put into motion it is possible to transfer energy to or from the "billiard ball" and, in some situations, the "ball" can even accelerate indefinitely (a process called FA). We found that the coupling between internal degrees of freedom and the center of mass of the system can diminish the rate of collisions with the moving wall and reduce the amount of energy gained by the particle. The second problem corresponds to the scattering of a composite particle by a Gaussian well. Our numerical simulations showed that this setting leads to the chaotic scattering of the composite particle, in the sense that similar impact parameters can lead to very different scattering angles. This behaviour was observed even when the internal potential was harmonic. The third problem corresponds to the possibility of reaching thermal equilibrium in a system with a small number of degrees of freedom. We studied the behaviour of a composite particle (constituted by three point particles) confined in a quartic well. Though this system is small we found that the kinetic energy of the center of mass can present features that resemble a thermalized system. These three problems may, on a first glance, seem unconnected from one another. But they all show how relevant the coupling between the internal degrees of freedom and the center of mass can be (AU) | |
| FAPESP's process: | 12/11271-2 - Vibrational modes as an external environment in molecular dynamics |
| Grantee: | Kellen Manoela Siqueira |
| Support Opportunities: | Scholarships in Brazil - Doctorate |