Eur. Phys. J. A (2019) 55: 104
https://doi.org/10.1140/epja/i2019-12772-8

Regular Article - Theoretical Physics

Radioactive beams and inverse kinematics: Probing the quantal texture of the nuclear vacuum

¹ Departamento de Fìsica Aplicada III, Escuela Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos, 41092, Sevilla, Spain
² National Superconducting Cyclotron Laboratory, Michigan State University, 48824, East Lansing, MI, USA
³ INFN Sezione di Milano, Via Celoria 16, I-20133, Milano, Italy
⁴ The Niels Bohr Institute, University of Copenhagen, DK-2100, Copenhagen, Denmark
⁵ Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, I-20133, Milano, Italy

^* e-mail: potel@nscl.msu.edu

Received: 17 December 2018
Accepted: 17 May 2019
Published online: 3 July 2019

Abstract

The properties of the quantum electrodynamic (QED) vacuum in general, and of the nuclear vacuum (ground) state in particular, are determined by virtual processes implying the excitation of a photon and of an electron-positron pair in the first case and of, for example, the excitation of a collective quadrupole surface vibration and a particle-hole pair in the nuclear case. Signals of these processes can be detected in the laboratory in terms of what can be considered a nuclear analogue of Hawking radiation. An analogy which extends to other physical processes involving QED vacuum fluctuations like the Lamb shift, pair creation by -rays, van der Waals forces and the Casimir effect, to the extent that one concentrates on the eventual outcome resulting by forcing a virtual process to become real, and not on the role of the black hole in defining the event horizon. In the nuclear case, the role of this event is taken over at a microscopic and fully quantum mechanical level, by nuclear probes (reactions) acting on virtual particles of the zero point fluctuations (ZPF) of the nuclear vacuum in a similar irreversible, no-return, fashion as the event horizon does, letting the other particle, entangled with the first one, escape to infinity, and eventually be detected. With this proviso in mind one can posit that the reactions ¹H(¹¹Be,¹⁰Be(2⁺;3.37MeV))²H and ¹H(¹¹Li,⁹Li(1/2^-;2.69MeV))³H together with the associated -decay processes indicate a possible nuclear analogy of Hawking radiation.