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I. L. Shapiro

Publications and source records attributed to I. L. Shapiro.

41 records · Page 3Linked to original sources
arXiv1994

Interaction of Low - Energy Induced Gravity with Quantized Matter and Phase Transition Induced by Curvature

At high energy scale the only quantum effect of any asymptotic free and asymptotically conformal invariant GUT is the trace anomaly of the energy-momentum tensor. Anomaly generates the new degree of freedom, that is propagating conformal factor. At lower energies conformal factor starts to interact with scalar field because of the violation of conformal invariance. We estimate the effect of such an interaction and find the running of the nonminimal coupling from conformal value $\frac{1}{6}$ to $0$. Then we discuss the possibility of the first order phase transition induced by curvature in a region close to the stable fixed point and calculate the induced values of Newtonian and cosmological constants.

hep-th↗
arXiv1994

Asymptotic Regimes in Quantum Gravity at Large Distances and Running Newtonian and Cosmological Constants

We consider a multiplicatively renormalizable higher-derivative scalar theory which is used as an effective theory for quantum gravity at large distances (infrared phase of quantum gravity). The asymptotic regimes (in particular, the asymptotically free infrared regime) for the coupling constants ---specifically the Newtonian and the cosmological constant--- are obtained. The running of the Newton and cosmological constants in the infrared asymptotically free regime may be relevant for solving the cosmological constant problem and for estimating the leading-log corrections to the static gravitational potential.

hep-th↗
arXiv1994

Hilbert - Einstein Action from Induced Gravity coupled with Scalar Field

Quantum theory of conformal factor coupled with matter fields is investigated. The more simple case of the purely classical scalar matter is considered. It is calculated the conformal factor contribution to the effective potential of scalar field. Then the possibility of the first order phase transition is explored and the induced values of Newtonian and cosmological constants are calculated.

hep-th↗
arXiv1994

One-Loop Renormalization and Asymptotic Behaviour of a Higher-Derivative Scalar Theory in Curved Spacetime

A higher-derivative, interacting, scalar field theory in curved spacetime with the most general action of sigma-model type is studied. The one-loop counterterms of the general theory are found. The renormalization group equations corresponding to two different, multiplicatively renormalizable variants of the same are derived. The analysis of their asymptotic solutions shows that, depending on the sign of one of the coupling constants, we can construct an asymptotically free theory which is also asymptotically conformal invariant at strong (or small) curvature. The connection that can be established between one of the multiplicatively renormalizable variants of the theory and the effective theory of the conformal factor, aiming at the description of quantum gravity at large distances, is investigated.

hep-th↗