arXiv subjects

D. Felea

Publications and source records attributed to D. Felea.

23 records · Page 2Linked to original sources

arXiv2010

Semiclassical study on Proton and Neutron

Starting from the existing semiclassical studies on hydrogenoid atoms, we propose a similar intuitive exercise for the three-body quark systems corresponding to protons and neutrons. In the frame of this toy model we try to explain both the stabilities of proton and neutron with respect to the nuclear interaction, and the spectrum of nucleonic resonances with J=1/2. Our choice is motivated also by a good agreement obtained for the up and down quark rest masses report. Taking into account the deterministic chaotic behavior of many-body systems, the discussed exercise could be understood as an interesting particular case of a quantum three-body problem which admits a semiclassical treatment.

nucl-th↗

arXiv2009

Visual tool for estimating the fractal dimension of images

This work presents a new Visual Basic 6.0 application for estimating the fractal dimension of images, based on an optimized version of the box-counting algorithm. Following the attempt to separate the real information from noise, we considered also the family of all band-pass filters with the same band-width (specified as parameter). The fractal dimension can be thus represented as a function of the pixel color code. The program was used for the study of paintings cracks, as an additional tool which can help the critic to decide if an artistic work is original or not. In its second version, the application was extended for working also with csv files and three-dimensional images.

physics.comp-ph↗

arXiv2009

Intermittency route to chaos for the nuclear billiard - a quantitative study

We extended a previous qualitative study of the intermittent behaviour of a chaotical nucleonic system, by adding a few quantitative analyses: of the configuration and kinetic energy spaces, power spectra, Shannon entropies, and Lyapunov exponents. The system is regarded as a classical "nuclear billiard" with an oscillating surface of a 2D Woods-Saxon potential well. For the monopole and dipole vibrational modes we bring new arguments in favour of the idea that the degree of chaoticity increases when shifting the oscillation frequency from the adiabatic to the resonance stage of the interaction. The order-chaos-order-chaos sequence is also thoroughly investigated and we find that, for the monopole deformation case, an intermittency pattern is again found. Moreover, coupling between one-nucleon and collective degrees of freedom is proved to be essential in obtaining chaotic states.

nucl-th↗

arXiv2009

Intermittency route to chaos for the nuclear billiard - a qualitative study

We analyze on a simple classical billiard system the onset of chaotical behaviour in different dynamical states. A classical version of the "nuclear billiard" with a 2D deep Woods-Saxon potential is used. We take into account the coupling between the single-particle and the collective degrees of freedom in the presence of dissipation for several vibrational multipolarities. For the considered oscillation modes an increasing divergence of the nucleonic trajectories from the adiabatic to the resonance regime was observed. Also, a peculiar case of intermittency is reached in the vicinity of the resonance, for the monopole case. We examine the order-to-chaos transition by performing several types of qualitative analysis including sensitive dependence on the initial conditions, single-particle phase space maps, fractal dimensions of Poincare maps and autocorrelation functions.

nucl-th↗

arXiv2009

Some phenomenological considerations on the nuclear collisions at high energies

We present some results obtained by applying the chaos theory on the numerical study of one threedimensional, relativistic, many-body quark system. The asymptotic freedom property is introduced by employing a harmonic term in the bi-particle potential. In this context, we used also the outcome of a semiclassical study, applied to the quark constituents of nucleons. Depending on the initial temperature parameter, the system can evolve toward an oscillating or an expansion regime. It is important to notice also a transition region, characterized by a partial fragmentation (higher degree of order). This effect can be observed near the critical temperature and is related to the partial overcoming of the potential barrier (corresponding to the farthest particles from the system). The degree of fragmentation is defined on the Shannon entropy basis and using the graphs theory. For analyzing the expansion tendency of one relativistic many-body system, we employed also the virial coefficient.

hep-ph↗