Eur. Phys. J. C (2012) 72: 2198
https://doi.org/10.1140/epjc/s10052-012-2198-4

Regular Article - Theoretical Physics

Cosmological perturbations in SFT inspired non-local scalar field models

¹ Theoretische Natuurkunde, Vrije Universiteit Brussel and The International Solvay Institutes, Pleinlaan 2, 1050, Brussels, Belgium
² Instituto de Ciencias del Espacio (ICE/CSIC) and Institut d’Estudis Espacials de Catalunya (IEEC), Facultat de Ciencies, Campus UAB, Torre C5-Par-2a pl, 08193, Bellaterra, Barcelona, Spain
³ Theoretical High Energy Physics Division, Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Leninskie Gory 1, 119991, Moscow, Russia

^* e-mail: svernov@theory.sinp.msu.ru

Received: 23 July 2012
Revised: 26 September 2012
Published online: 31 October 2012

Abstract

We study cosmological perturbations in models with a single non-local scalar field originating from the string field theory description of the rolling tachyon dynamics. We construct the equation for the energy density perturbations of the non-local scalar field and explicitly prove that for the free field it is identical to a system of local cosmological perturbation equations in a particular model with multiple (maybe infinitely many) local free scalar fields. We also show that vector and tensor perturbations are absent in this set-up.