Constraints on Flows in Horava-Lifshitz Gravity by Classical Solutions
  We find exact static stringy solutions of Horava-Lifshitz gravity with the
projectability condition but imposing the detailed balance condition near the
UV fixed point, and propose a method on constraining the possible pattern of
flows in Horava-Lifshitz gravity by using the obtained classical solutions. In
the obtained vacuum solutions, the parameters related to the speed of the
graviton and the coefficients of quartic spatial derivative terms lead to
intriguing effects: the change of graviton speed yields a surplus angle and the
quartic derivatives make the square of effective electric charge negative. The
result of a few tests based on the geometries of a cone, an excess cone, a
black string, and a charged (black) string seems suggestive. For example, the
flow of constant graviton speed and variable Newton's coupling can be favored
in the vicinity of IR fixed point, but the conclusion is indistinct and far
from definite yet. Together with the numerous classical solutions, static or
time-dependent, which have already been found, the accumulated data from
various future tests will give some hints in constraining the flow patterns
more deterministic.
