4 research outputs found
Quantum gravity correction, evolution of scalar field and inflation
We take the first nontrivial coefficient of the Schwinger-DeWitt expansion as
a leading correction to the action of the second-derivative metric-dilaton
gravity. To fix the ambiguities related with an arbitrary choice of the gauge
fixing condition and the parametrization for the quantum field, one has to use
the classical equations of motion. As a result, the only corrections are the
ones to the potential of the scalar field. It turns out that the parameters of
the initial classical action may be chosen in such a way that the potential
satisfies most of the conditions for successful inflation.Comment: 11 pages, 3 figure
One-loop corrections to the photon propagator in the curved-space QED
We calculate and discuss the one-loop corrections to the photon sector of QED
interacting to a background gravitational field. At high energies the fermion
field can be taken as massless and the quantum terms can be obtained by
integrating conformal anomaly. We present a covariant local expression for the
corresponding effective action, similar to the one obtained earlier for the
gravitational sector. At the moderate energies the quantum terms can be
obtained through the heat kernel method. In this way we derive the exact
one-loop beta-function for the electric charge in the momentum subtraction
scheme and explore both massless and large mass limits. The relation between
the two approaches is shown and the difference discussed in view of the
possible applications to cosmology and astrophysics.Comment: 17 pages, PRD format, 4 figures. Two references added, a few English
mistakes fixed, closely fits published versio