3 research outputs found
One Loop Beta Functions in Topologically Massive Gravity
We calculate the running of the three coupling constants in cosmological,
topologically massive 3d gravity. We find that \nu, the dimensionless
coefficient of the Chern-Simons term, has vanishing beta function. The flow of
the cosmological constant and Newton's constant depends on \nu, and for any
positive \nu there exist both a trivial and a nontrivial fixed point.Comment: 44 pages, 16 figure
Renormalization Group Flow in Scalar-Tensor Theories. II
We study the UV behaviour of actions including integer powers of scalar
curvature and even powers of scalar fields with Functional Renormalization
Group techniques. We find UV fixed points where the gravitational couplings
have non-trivial values while the matter ones are Gaussian. We prove several
properties of the linearized flow at such a fixed point in arbitrary dimensions
in the one-loop approximation and find recursive relations among the critical
exponents. We illustrate these results in explicit calculations in for
actions including up to four powers of scalar curvature and two powers of the
scalar field. In this setting we notice that the same recursive properties
among the critical exponents, which were proven at one-loop order, still hold,
in such a way that the UV critical surface is found to be five dimensional. We
then search for the same type of fixed point in a scalar theory with minimal
coupling to gravity in including up to eight powers of scalar curvature.
Assuming that the recursive properties of the critical exponents still hold,
one would conclude that the UV critical surface of these theories is five
dimensional.Comment: 14 pages. v.2: Minor changes, some references adde