Regular Article

Entanglement in anisotropic expanding spacetime^★

¹ Institute of Theoretical Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
² University of Calgary, Department of Geoscience, Calgary, Canada
³ School of Science and Technology, University of Camerino, 62032 Camerino, Italy
⁴ INFN-Sezione di Perugia, 06123 Perugia, Italy

^a e-mail: stefano.mancini@unicam.it

Received: 30 August 2018
Received in final form: 8 December 2018
Published online: 12 February 2019

Abstract

We study the effect of space anisotropy in the entanglement generated by expanding universe on spin 0 and 1/2 fields. For massive scalar field we find revivals of entanglement entropy vs. momentum after decreasing from the maximum at k = 0. In massive Dirac field the effect is a slight distortion of the non-monotonic profile giving rise to the maximum of entanglement entropy at k > 0. More interestingly, massless field of both type show that can only get entangled through anisotropy, with a maximum of entanglement entropy occurring at k > 0.