Virtual coupling potential for elastic scattering of 10,11^{10,11}Be on proton and carbon targets

International audienceThe 10;11Be(p,p) and (12C, 12C) reactions were analyzed to determine the in uence of the weak binding energies of exotic nuclei on their interaction potential. The elastic cross sections were measured at GANIL in inverse kinematics using radioactive 10;11Be beams produced at energies of 39:1 A and 38:4A MeV. The elastic proton scattering data were analyzed within the framework of the microscopic Jeukenne-Lejeune-Mahaux (JLM) nucleon-nucleus potential. The angular distributions are found to be best reproduced by reducing the real part of the microscopic optical potential, as a consequence of the coupling to the continuum. These effects modify deeply the elastic potential. Including the Virtual Coupling Potential (VCP), we show the ability of the general optical potentials to reproduce the data for scattering of unstable nuclei, using realistic densities. Finally, the concepts needed to develop a more general and microscopic approach of the VCP are discussed

Coupling effects in the elastic scattering of 6^{6}He on 12^{12}C

To study the effect of the weak binding energy on the interaction potential between a light exotic nucleus and a target, elastic scattering of 6He at 38.3 MeV/nucleon on a 12C target was measured at Grand Accélérateur National d'Ions Lourds (GANIL). The 6He beam was produced by fragmentation. The detection of the scattered particles was performed by the GANIL spectrometer. The energy resolution was good enough to separate elastic from inelastic scattering contributions. The measured elastic data have been analyzed within the optical model, with the real part of the optical potential calculated in the double-folding model using a realistic density-dependent nucleon-nucleon interaction and the imaginary part taken in the conventional Woods-Saxon (WS) form. A failure of the "bare" real folded potential to reproduce the measured angular distribution over the whole angular range suggests quite a strong coupling of the higher-order breakup channels to the elastic channel. To estimate the strength of the breakup effects, a complex surface potential with a repulsive real part (designed to simulate the polarization effects caused by the projectile breakup) was added to the real folded and imaginary WS potentials. A realistic estimate of the polarization potential caused by the breakup of the weakly bound 6He was made based on a parallel study of 6He+12C and 6Li+12C optical potentials at about the same energies

First steps toward artificial culture in robot societies

This poster abstract outlines initial results from a multi-disciplinary research project called ‘the emergence of artificial culture in robot societies’ whose overall aim is to investigate the processes and mechanisms by which protocultural behaviours, better described as traditions, might emerge in a free running collective robot system. We accept, as a working hypothesis, the idea that mimesis and embodiment are essential pre-requisites for cultural evolution [1]. It follows that since our aim is to demonstrate artificial culture we need a system of embodied artificial agents, i.e. robots, in which robots are able to learn socially from each other, by imitation. This group of robots, which we call ‘Copybots’ (after [1] pp106-107), require an environment in which behaviours can be copied, by imitation, from one robot to another and we refer to this environment as the ‘artificial culture lab’