Oscillating Universe in Horava-Lifshitz Gravity
  We study the dynamics of isotropic and homogeneous universes in the
generalized Ho\v{r}ava-Lifshitz gravity, and classify all possible evolutions
of vacuum spacetime. In the case without the detailed balance condition, we
find a variety of phase structures of vacuum spacetimes depending on the
coupling constants as well as the spatial curvature $K$ and a cosmological
constant $\Lambda$. A bounce universe solution is obtained for $\Lambda> 0,
K=\pm 1$ or $\Lambda= 0, K=- 1$, while an oscillation spacetime is found for
$\Lambda\geq 0, K=1$, or $\Lambda< 0, K=\pm 1$. We also propose a quantum
tunneling scenario from an oscillating spacetime to an inflationary universe,
resulting in a macroscopic cyclic universe.
