Covariant Lagrange multiplier constrained higher derivative gravity with scalar projectors

We formulate higher derivative gravity with Lagrange multiplier constraint and scalar projectors. Its gauge-fixed formulation as well as vector fields formulation is developed and corresponding spontaneous Lorentz symmetry breaking is investigated. We show that the only propagating mode is higher derivative graviton while scalar and vector modes do not propagate. Despite to higher derivatives structure of the action, its first FRW equation is the first order differential equation which admits the inflationary universe solution.Comment: Physics Letters B published version. LaTeX 12 page

Hamiltonian Analysis of the Higgs Mechanism for Graviton

In this paper we perform the canonical description of the Higgs mechanism for gravity and provide the Hamiltonian definition of the massive gravities.Comment: 18 page

Higher derivative gravity with spontaneous symmetry breaking: Hamiltonian analysis of new covariant renormalizable gravity

In order to explore some general features of modified theories of gravity which involve higher derivatives and spontaneous Lorentz and/or diffeomorphism symmetry breaking, we study the recently proposed new version of covariant renormalizable gravity (CRG). CRG attains power-counting renormalizability via higher derivatives and introduction of a constrained scalar field and spontaneous symmetry breaking. We obtain an Arnowitt-Deser-Misner representation of the CRG action in four-dimensional spacetime with respect to a foliation of spacetime adapted to the constrained scalar field. The resulting action is analyzed by using Hamiltonian formalism. We discover that CRG contains two extra degrees of freedom. One of them carries negative energy (a ghost) and it will destabilize the theory due to its interactions. This result is in contrast with the original paper [Phys. Lett. B 701, 117 (2011), arXiv:1104.4286 [hep-th]], where it was concluded that the theory is free of ghosts and renormalizable when we analyze fluctuations on the flat background.Comment: 39 pages. Presentation improved. Version published in Phys. Rev.

Note About Hamiltonian Formalism of Healthy Extended Horava-Lifshitz Gravity

In this paper we continue the study of the Hamiltonian formalism of the healthy extended Horava-Lifshitz gravity. We find the constraint structure of given theory and argue that this is the theory with the second class constraints. Then we discuss physical consequence of this result. We also apply the Batalin-Tyutin formalism of the conversion of the system with the second class constraints to the system with the first class constraints to the case of the healthy extended Horava-Lifshitz theory. As a result we find new theory of gravity with structure that is different from the standard formulation of Horava-Lifshitz gravity or General Relativity.Comment: 17 pages, v.2. references added, v.3. typos corrected, references adde

Note About Integrability and Gauge Fixing for Bosonic String on AdS(5)xS(5)

This short note is devoted to the study of the integrability of the bosonic string on AdS(5)xS(5) in the uniform light-cone gauge. We construct Lax connection for gauge fixed theory and we argue that it is flat.Comment: 17 page

On the Universal Tachyon and Geometrical Tachyon

We study properties of non-BPS D(p+1)-brane in the background of k NS5-branes, with one transverse direction compactified on a circle, from the point of view of Dirac-Born-Infeld action. We present the analysis of two different embedding of non-BPS D(p+1)-brane in given background and study the classical solutions of given world-volume theory. We argue for the configuration of a non-BPS D(p+1)-brane which allows us to find solutions of the equations of motion that give unified descriptions of G and U-type branes.Comment: 24 pages, minor change