Holography beyond conformal invariance and AdS isometry?

Journal of Experimental and Theoretical Physics - We suggest that the principle of holographic duality be extended beyond conformal invariance and AdS isometry. Such an extension is based on a...     

Why there is something rather than nothing: cosmological constant from summing over everything in lorentzian quantum gravity

The density matrix of the Universe for the microcanonical ensemble in quantum cosmology describes an equipartition in the physical phase space of the theory (sum over everything), but in terms of the observable spacetime geometry this ensemble is peaked about the set of recently obtained cosmological instantons limited to a bounded range of the cosmological constant. This suggests the mechanism of constraining the landscape of string vacua and a possible solution to the dark energy problem in the form of the quasiequilibrium decay of the microcanonical state of the Universe.     

The double dimensional regularization and gauge theories without ghosts

A new version of dimensional regularization is introduced as calculational technique for the recently proposed gauge theory without ghosts. The method is applied to Yang-Mills theory.     

Infrared Asymptotics of the Heat Kernel and Nonlocal Effective Action

We review recent results in the nonperturbative theory of the heat kernel and its late-time asymptotic properties responsible for the infrared behavior of the quantum effective action for massless theories. In particular, we derive a generalization of the Coleman-Weinberg potential for theories with an inhomogeneous background field. This generalization represents a new nonlocal, nonperturbative action accounting for the effects in a transition domain between the space-time interior and its infinity. In four dimensions, these effects delocalize the logarithmic Coleman-Weinberg potential, while in d > 4, they are dominated by a new powerlike, renormalization-independent nonlocal structure. We also consider the nonperturbative behavior of the heat kernel in a curved space-time with an asymptotically flat geometry. In particular, we analyze the conformal properties of the heat kernel for a conformally invariant scalar field and discuss the problem of segregating the local cosmological term from the nonlocal effective action.This paper was written at the request of the Editorial Board.__________Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 143, No. 3, pp. 328–356, June, 2005.     

Tunneling cosmological state and the origin of Higgs inflation in the standard model

For the tunneling cosmological state, we propose a path integral formulation admitting a consistent renormalization and renormalization-group improvement in particle physics applications of quantum cosmology with heavy massive quantum fields. We apply this formulation to the inflationary cosmology driven by the standard-model Higgs boson playing the role of an inflaton with a strong nonminimal coupling to gravity. A complete cosmological scenario is thus obtained, embracing the formation of initial conditions for the inflationary background in the form of a sharp probability peak in the distribution of the inflaton field and the ongoing generation of the cosmic microwave background spectrum on this background. We also discuss the status of the no-boundary and tunneling states in a cosmology driven by massless fields conformally coupled to gravity.     

Dark energy and dark matter from nonlocal ghost-free gravity theory

We suggest a class of generally covariant ghost-free nonlocal gravity models generating de Sitter or anti-de Sitter background with an arbitrary value of the effective cosmological constant and featuring a mechanism of dark matter simulation. These models interpolate between the general relativistic phase on a flat spacetime background and their strongly coupled infrared (anti-)de Sitter phase with two propagating massless graviton modes.