Application of the ising model to the study of cluster multiplicities in finite excited systems

Fragmentation is expected to be an experimental signal which can give some information about the physical characteristics of finite excited systems. We try to investigate the question concerning the mechanism which governs the onset of the disassembly of such systems in connection with their internal dynamics. We restrict this study to the case where the systems are in thermodynamical equilibrium. We use the 2-dimensional Ising model as a generic model in order to calculate the multiplicities for the formation of strongly bound clusters inside the system and analyse their behaviour as a function of the temperature. The calculated observables show features which reflect the role played by the internal dynamics. The evolution of the shape of the cluster multiplicities with temperature obtained in the present study is qualitatively the same as the one which comes out through different nuclear phase space fragmentation models.     

Role of single particle transfer in heavy ion fusion

Fusion excitation functions in heavy ion collision have been calculated taking into account the effect of random transfer of single particles in a classical dynamical model. The model has been applied to fusion of ¹⁶O+²⁷Al and ⁴⁰Ar +¹⁰⁹Ag. The transfer does not affect the low energy fusion excitation function but the effect of transfer is appreciable for high energies.     

Entropic Leggett–Garg inequality in neutrinos and <Emphasis Type="Italic">B</Emphasis>(<Emphasis Type="Italic">K</Emphasis>) meson systems

Entropic Leggett–Garg inequality is studied in systems like neutrinos in the context of two and three flavor neutrino oscillations and in neutral \(B_d\), \(B_s\) and K mesons. The neutrino dynamics is described with the matter effect taken into consideration. For the decohering B / K meson systems, the effect of decoherence and CP violation have also been taken into account, using the techniques of open quantum systems. Enhancement in the violation with increase in the number of measurements has been found, in consistency with findings in spin-s systems. The effect of decoherence is found to bring the deficit parameter \(\mathscr {D}^{[n]}\) closer to its classical value zero, as expected. The violation of entropic Leggett–Garg inequality lasts for a much longer time in K meson system than in \(B_d\) and \(B_s\) systems.