arXiv subjects

Mario Castagnino

Publications and source records attributed to Mario Castagnino.

58 records · Page 4Linked to original sources

arXiv1999

From classical chaos to decoherence in Robertson-Walker cosmology

We analyse the relationship between classical chaos and particle creation in Robertson-Walker cosmological models with gravity coupled to a scalar field. Within our class of models chaos and particle production are seen to arise in the same cases. Particle production is viewed as the seed of decoherence, which both enables the quantum to classical transition, and ensures that the correspondence between the quantum and classically chaotic models will be valid

gr-qc↗

arXiv1998

Chaos in Robertson-Walker Cosmology

Chaos in Robertson-Walker cosmological models where gravity is coupled to one or more scalar fields has been studied by a few authors, mostly using numerical simulations. In this paper we begin a systematic study of the analytical aspect. We consider one conformally coupled scalar field and, using the fact that the model is integrable when the field is massless, we show in detail how homoclinic chaos arises for nonzero masses using a perturbative method.

gr-qc↗

arXiv1996

Minimal Irreversible Quantum Mechanics

It is demonstrated that, making minimal changes in ordinary quantum mechanics, a reasonable irreversible quantum mechanics can be obtained. This theory has a more general spectral decompositions, with eigenvectors corresponding to unstable states that vanish when $t \to \infty .$ These ''Gamov vectors'' have zero norm, in such a way that the norm and the energy of the physical states remain constant. The evolution operator has no inverse, showing that we are really dealing with a time-asymmetric theory. Using Friedrichs model reasonable physical results are obtained, e. g. : the remaining of an unstable decaying state reappears, in the continuous spectrum of the model, with its primitive energy.

quant-ph↗

arXiv1996

The Mathematical Structure of Superspace as a Consequence of Time Asymmetry

It is demonstrated how a convenient choice of the mathematical structure of the quantum cosmology superspace, precisely the definition of a convenient regular state superspace and the restriction of the dynamics to this space, yields directly to an irreversible evolution, in the classical (and semiclassical) phase of the universe, where: Decoherence and correlations take place and therefore give origin to a classical universe. The second law of thermodynamic is demonstrated. Connection with Reichenbach branch system idea can be implemented. Some rough coincidence with observational data are obtained. The arrows of time can be correlated. Time asymmetry can be explained as a state space asymmetry (e. g. like a spontaneous symmetry breaking All these facts solve the problem of time-asymmetry and show that it is time asymmetry itself that defines the most important features of mathematical structure of superspace.

gr-qc↗