A unified approach to variational derivatives of modified gravitational actions
Küçük Resim Yok
Tarih
2011
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
IOP PUBLISHING LTD
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Our main aim in this paper is to promote the coframe variational method as a unified approach to derive field equations for any given gravitational action containing the algebraic functions of the scalars constructed from the Riemann curvature tensor and its contractions. We are able to derive a master equation which expresses the variational derivatives of the generalized gravitational actions in terms of the variational derivatives of its constituent curvature scalars. Using the Lagrange multiplier method relative to an orthonormal coframe, we investigate the variational procedures for modified gravitational Lagrangian densities in spacetime dimensions n >= 3. We study the well-known gravitational actions such as those involving the Gauss-Bonnet and Ricci-squared, Kretchmann scalar, Weyl-squared terms and their algebraic generalizations similar to generic f(R) theories and the algebraic generalization of sixth order gravitational Lagrangians. We put forth a new model involving the gravitational Chern-Simons term and also give three-dimensional new massive gravity equations in a new form in terms of the Cotton 2-form.
Açıklama
Anahtar Kelimeler
Kaynak
CLASSICAL AND QUANTUM GRAVITY
WoS Q Değeri
Q1
Scopus Q Değeri
Q1
Cilt
28
Sayı
1
