Cluster of nucleons as elementary modes of excitation in nuclei

Conditions which must be fulfilled by clusters of nucleons to qualify as elementary modes of excitation are analysed in terms of simple criteria involving experimental binding energies. It is found that the most complex possible mode is the α-like cluster.     

Shape-phase transitioners as pairing back benders

A semiclassical analysis of pairing vibrational and rotational bands is performed. The empirical pairing moment of inertia is found to present a “back bending” behavior whenever a shape-phase transition takes place. A phenomenological calculation for the Sm isotopes is performed.     

Wein

Ohne Zusammenfassung     

On the dynamics of a single-bit stochastic-resonance memory device

The increasing capacity of modern computers, driven by Moore’s Law, is accompanied by smaller noise margins and higher error rates. In this paper we propose a memory device, consisting of a ring of two identical overdamped bistable forward-coupled oscillators, which may serve as a building block in a larger scale solution to this problem. We show that such a system is capable of storing a single bit and its performance improves with the addition of noise. The proposed device can be regarded as asynchronous, in the sense that stored information can be retrieved at any time and, after a certain synchronization time, the probability of erroneous retrieval does not depend on which oscillator is being interrogated. We characterize memory persistence time and show it to be maximized for the same noise range that both minimizes the probability of error and ensures synchronization. We also present experimental results for a hard-wired version of the proposed memory, consisting of a loop of two Schmitt triggers. We show that this device is capable of storing a single bit and does so more efficiently in the presence of noise.     

Self consistent description of the interplay between shape and pairing deformations: Static properties

The competition between pairing and multipole fields is studied within the framework of a two-level model, employing different theoretical approaches. The importance of a self-consistent tretment is clearly revealed. Special attention is payed to the microscopic mechanisms that take place when the system undergoes various phase transitions.     

The RPA of renormalized fermions

The RPA modes are constructed using data associated with different kinds of renormalized one-particle Green functions as input. A general normalization condition is derived and the formalism applied to the ⁴⁰Ca nucleus.     

The monoclinic/orthorhombic phase transition in Ba2Cu(HCOO)6: An optical and x-ray powder diffraction study

α-Ba₂Cu(HCOO)₆ grown at room temperature crystallizes in space group P2₁. On heating a reversible, hysteretic, equitranslational, first-order phase transition at about 60-90°C takes place. Here we discuss the influence of thermal treatments on the occurrence, coexistence and stability ranges of the two observed phases, as studied by several techniques (optical microscopy, differential scanning calorimetry and X-ray diffraction). On cooling a single set of domain walls parallel to (001) have been observed. Taking into account experimental results and the crystal pseudosymmetry of the α phase we propose that the high-temperature β phase crystallizes in space group Pbnm.