Bruno Vieira Ribeiro | Searcharxiv

arXiv2013

Ornstein-Uhlenbeck limit for the velocity process of an $N$-particle system interacting stochastically

An $N$-particle system with stochastic interactions is considered. Interactions are driven by a Brownian noise term and total energy conservation is imposed. The evolution of the system, in velocity space, is a diffusion on a $(3N-1)$-dimensional sphere with radius fixed by the total energy. In the $N\rightarrow\infty$ limit, a finite number of velocity components are shown to evolve independently and according to an Ornstein-Uhlenbeck process.

math-ph↗

arXiv2013

Collective modes in free plasmas subjected to a radiation field

In this study we report the effects of an external electromagnetic field on the collective properties of unmagnetized plasmas. The calculations are carried out in the semi-classical approximation, i.e., the electromagnetic field is treated classically and the electrons from a quantum mechanical viewpoint. The results show that the collective modes are damped away more smoothly and in a smaller frequency range than those reported by previous studies. An exponential-like decay of the plasmon frequencies as a function of the external field amplitude is readily observed. We successfully recreate the results of previous studies. We also find that the single photon processes has a pronounced effect on the decrease of the frequency range of modulation.

quant-ph↗