Eur. Phys. J. C (2012) 72: 2068
https://doi.org/10.1140/epjc/s10052-012-2068-0

Review

Hamiltonian dynamics and Noether symmetries in Extended Gravity Cosmology

¹ Dipartimento di Scienze Fisiche, Università di Napoli “Federico II”, Edificio G, Via Cinthia, 80126, Napoli, Italy
² INFN sez. di Napoli, Compl. Univ. di Monte S. Angelo, Edificio G, Via Cinthia, 80126, Napoli, Italy
³ Istitucio Catalana de Recerca i Estudis Avancats (ICREA) and Consejo Superior de Investigaciones Cientificas, ICE/CSIC and Institut de Ciencies de l Espai (IEEC-CSIC), Campus UAB, Facultat de Ciencies, Torre C5-Par-2a pl, 08193, Bellaterra, Barcelona, Spain

^* e-mail: capozziello@na.infn.it

Received: 28 April 2012
Published online: 17 July 2012

Abstract

We discuss the Hamiltonian dynamics for cosmologies coming from Extended Theories of Gravity. In particular, minisuperspace models are taken into account searching for Noether symmetries. The existence of conserved quantities gives selection rule to recover classical behavior in cosmic evolution according to the so-called Hartle criterion, which allows one to select correlated regions in the configuration space of dynamical variables. We show that such a statement works for general classes of Extended Theories of Gravity and is conformally preserved. Furthermore, the presence of Noether symmetries allows a straightforward classification of singularities that represent the points where the symmetry is broken. Examples for non-minimally coupled and higher-order models are discussed.