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Seminar | Physics

Nuclear Josephson-like γ-emission

PHY Seminar

Abstract: Nucleon pair transfer processes between superfluid nuclei in heavy ion reactions are considered as possible analogues of the transfer of Cooper pairs of electrons through Josephson Junctions (JJ). A particular signature of this analogy concerns the dependence of absolute pair transfer cross sections on the number of transferred pairs. In this talk, we present a novel approach to the study of the above analogy, based on the alternating current (ac) Josephson effect and associated electromagnetic radiation emitted in the process, for which the consideration of one nuclear Cooper pair transfer, together with the corresponding one-nucleon transfer process, leads to a direct identification of the nuclear Josepson-like effect.

In this work we implement the quantum mechanical description of the coupling of the electric dipole associated with the (2n)-transfer reaction process with the electromagnetic field, establishing the connection between the dynamics of the collision process and the number and energy dependence of the emitted γ photons, thus providing a robust quantitative signature of the (ac) Josephson-like nature of the phenomenon. We will also comment on a most important result of our collaboration with the LNL (L. Corradi and S. Szilner), namely the recently performed first experiment specifically dedicated to test our predictions.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.