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Nuclear Theory·nucl-th

Wednesday·June 5, 2019

7 papers—5 primary·2 cross-listed

All7Primary5Cross-lists2
  1. 06

    Kramers's escape rate problem within a non-Markovian description

    Benjamin Schüller🇩🇪 · Alex Meistrenko🇩🇪 · Hendrik van Hees🇩🇪 · Zhe Xu🇨🇳 · Carsten Greiner🇩🇪

    We compare the thermal escape rates of a Brownian particle, initially trapped into one of the two wells of an asymmetric double-well potential, for thermal Markovian and non-Markovian noise. The Markovian treatment of this problem goes originally back to the studies of Kramers in 1940 and is therefore often referred to as "Kramers's escape rate problem". We solve the generalized Langevin equation for the trajectories of the particles numerically and analytically for both limiting cases, Markovian and non-Markovian thermal noise. We compute the escape rate and work out the fundamental differences arising from finite correlation times of the thermal noise.

    ↳ cond-mat.stat-mechhep-phnucl-thAnnals Phys.(2020)·7 citations
  2. 07

    Effects of one valence proton on seniority and angular momentum of neutrons in neutron-rich Sb isotopes

    S. Biswas🇫🇷 · A. Lemasson🇫🇷 · M. Rejmund🇫🇷 · A. Navin🇫🇷 · Y.H. Kim🇫🇷 · C. Michelagnoli🇫🇷 · I. Stefan🇫🇷 · R. Banik🇮🇳 · P. Bednarczyk🇵🇱 · S. Bhattacharya🇮🇳 · S. Bhattacharyya🇮🇳 · E. Clément🇫🇷 and 49 other authors

    The neutron-rich Sb isotopes were produced as fission fragments in the reaction Be(U,~f) with 6.2 MeV/u beam energy. An unique setup, consisting of AGATA, VAMOS++ and EXOGAM detectors, was used which enabled the prompt-delayed gamma-ray () spectroscopy of fission fragments in the time range of 100 ns - 200 s. New isomers, prompt and delayed transitions were established in the even-A Sb isotopes. In the odd-A Sb isotopes, new prompt and delayed -ray transitions were identified, in addition to the confirmation of the previously known isomers. The half-lives of the isomeric states and the transition probabilities of the observed transitions depopulating these isomers were extracted. The experimental data was compared with the theoretical results obtained in the framework of Large-Scale Shell-Model (LSSM) calculations in a restricted model space. Modifications of several components of the shell model interaction were introduced to obtain a consistent agreement with the excitation energies and the transition probabilities in neutron-rich Sn and Sb isotopes. The isomeric configurations in Sn and Sb were found to be relatively pure. Further, the calculations revealed that the presence of a single valence proton, mainly in the orbital in Sb isotopes, leads to significant mixing (due to the interaction) of: (i) the neutron seniorities () and (ii) the neutron angular momentum (). The above features have a weak impact on the excitation energies, but have an important impact on the transition probabilities. In addition, a constancy of the relative excitation energies irrespective of neutron seniority and neutron number in Sn and Sb was observed.

    ↳ nucl-exnucl-thPRC(2019)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE