8 research outputs found
Interaction of Low - Energy Induced Gravity with Quantized Matter -- II. Temperature effects
At the very early Universe the matter fields are described by the GUT models
in curved space-time. At high energies these fields are asymptotically free and
conformally coupled to external metric. The only possible quantum effect is the
appearance of the conformal anomaly, which leads to the propagation of the new
degree of freedom - conformal factor. Simultaneously with the expansion of the
Universe, the scale of energies decreases and the propagating conformal factor
starts to interact with the Higgs field due to the violation of conformal
invariance in the matter fields sector. In a previous paper \cite{foo} we have
shown that this interaction can lead to special physical effects like the
renormalization group flow, which ends in some fixed point. Furthermore in the
vicinity of this fixed point there occur the first order phase transitions. In
the present paper we consider the same theory of conformal factor coupled to
Higgs field and incorporate the temperature effects. We reduce the complicated
higher-derivative operator to several ones of the standard second-derivative
form and calculate an exact effective potential with temperature on the anti de
Sitter (AdS) background.Comment: 12 pages, LaTex - 2 Figure
On the conformal transformation and duality in gravity
The theory described by the sum of the Einstein-Hilbert action and the action
of conformal scalar field possesses the duality symmetry which includes some
special conformal transformation of the metric, and also inversion of scalar
field and of the gravitational constant. In the present paper the conformal
duality is generalized for arbitrary space-time dimension and for
the general sigma-model type conformal scalar theory. We also consider to apply
the conformal duality for the investigation of quantum gravity in the strong
curvature regime. The trace of the first coefficient of the Schwinger-DeWitt
expansion is derived and it's dependence on the gauge fixing condition is
considered. After that we discuss the way to extract the gauge-fixing
independent result and also it's possible physical applications.Comment: LaTeX, 15 pages, no figures. To appear in Classical and Quantum
Gravit
Conformal anomaly for 2d and 4d dilaton coupled spinors
We study quantum dilaton coupled spinors in two and four dimensions. Making
classical transformation of metric, dilaton coupled spinor theory is
transformed to minimal spinor theory with another metric and in case of 4d
spinor also in the background of the non-trivial vector field. This gives the
possibility to calculate 2d and 4d dilaton dependent conformal (or Weyl)
anomaly in easy way. Anomaly induced effective action for such spinors is
derived. In case of 2d, the effective action reproduces, without any extra
terms, the term added by hands in the quantum correction for RST model, which
is exactly solvable. For 4d spinor the chiral anomaly which depends explicitly
from dilaton is also found. As some application we discuss SUSY Black Holes in
dilatonic supergravity with WZ type matter and Hawking radiation in the same
theory. As another application we investigate spherically reduced Einstein
gravity with 2d dilaton coupled fermion anomaly induced effective action and
show the existence of quantum corrected Schwarszchild-de Sitter (SdS) (Nariai)
BH with multiple horizon.Comment: LaTeX file, 15 page
A Four-Dimensional Theory for Quantum Gravity with Conformal and Nonconformal Explicit Solutions
The most general version of a renormalizable theory corresponding to a
dimensionless higher-derivative scalar field model in curved spacetime is
explored. The classical action of the theory contains independent
functions, which are the generalized coupling constants of the theory. We
calculate the one-loop beta functions and then consider the conditions for
finiteness. The set of exact solutions of power type is proven to consist of
precisely three conformal and three nonconformal solutions, given by remarkably
simple (albeit nontrivial) functions that we obtain explicitly. The finiteness
of the conformal theory indicates the absence of a conformal anomaly in the
finite sector. The stability of the finite solutions is investigated and the
possibility of renormalization group flows is discussed as well as several
physical applications.Comment: LaTeX, 18 pages, no figure