We have investigated the effect of friction on the DCC domain formation. We solve the Newton equation of motion for the O(4) fields, with quenched initial condition. The initial fields are randomly distributed in a Gaussian form. In one dimensional expansion, on the average, large DCC domains can not be formed. However, in some particular orbits, large instabilities may occur. This possibility ...

A reconstruction method for recovering the initial conditions of the Universe starting from the present galaxy distribution is presented which guarantees uniqueness of solutions. We show how our method can be used to obtain the peculiar velocities of a large number of galaxies, hence trace galaxies orbits back in time and obtain the entire past dynamical history of the Universe above scales whe...

We present a simplified dynamical model of the “Bullet” system of two colliding clusters. The model constrains the masses of the system by requiring that the orbits of the main and sub components satisfy the cosmological initial conditions of vanishing physical separation a Hubble time ago. This is also known as the timing argument. The model considers a system embedded in an over-dense region....

The security of chaos-based cryptosystems is closely related to the possibility of recovering control parameters and/or initial conditions from partial information on the associated chaotic orbits. In this paper we analyze this possibility for the case of unimodal maps. We show a meaningful set of contexts where the dynamics of unimodal maps can be reconstructed, which means a relevant reductio...

The orbital motion of the planets in the Solar System is chaotic. As a result, initially close orbits diverge exponentially with a characteristic Lyapunov time of 5 Ma. This sensitivity to initial conditions will limit the possibility of obtaining an accurate solution for the orbital and precessional motion of the Earth over more than 35– 50 Ma. The principal sources of uncertainty in the model...

A new class of multivariate probability density functions is proposed called the Gauss von Mises (GVM) family of distributions. The distinguishing feature of the GVM distribution is its definition on a cylindrical manifold, the underlying state space in which systems of orbital element coordinates are more accurately defined, which can provide a statistically rigorous treatment of uncertainty n...

This paper aims at investigating the performance of a LIDAR-based system for pose determination of a known debris. A customized template matching technique is implemented for pose initial acquisition, while pose tracking is carried out by Iterative Closest Point algorithms based on different matching approaches. In order to evaluate the achievable accuracy in pose estimation, a numerical simula...

Orbit determination and control problems are sometimes solved using linearized methods, even though nonlinear effects can sometimes dominate the system. This paper addresses ways to parallelize computational algorithms for numerical integrators and nonlinear relative motion equations. An application of the proposed methods to mutual gravitation of a fragmented asteroid is presented, with analys...