BLACK HOLE THERMODYNAMIC FLUCTUATIONS AND PHASE TRANSITION OF IR MODIFIED HOŘAVA–LIFSHITZ GRAVITY

Hořava–Lifshitz theory as a renormalizable model of gravity might be an ultraviolet (UV) completion of general relativity (GR) and it reduces to Einstein gravity with a nonvanishing cosmological constant in infrared (IR) approximation. Kehagias and Sfetsos have added a relevant operator proportional to the three-dimensional (3D) geometry Ricci scalar to the original Hořava–Lifshitz theory action and obtained a spherically symmetric asymptotically flat black hole solution called Kehagias–Sfetsos (KS) black hole. Nonequilibrium thermodynamic fluctuations based on the metric of a KS black hole in IR modified Hořava–Lifshitz gravity have been calculated. It is concluded that the second-order momentum of mass flux is nondivergent and phase transition does not occur at the extremal case, while phase transition occurs at some other case, which is also different from the common case when the heat capacity is divergent.

NEUTRINO TRIBIMAXIMAL MIXING FROM A4 ALONE

Neutrino tribimaximal mixing is obtained from the breaking of A4 to Z3 in the charged-lepton sector and to Z2 in the neutrino sector. To enforce this conflicting pattern, extra particles and symmetries are usually invoked, often accompanied by nonrenormalizable interactions and even extra dimensions. It is shown here in a specific renormalizable model how A4 alone will accomplish this, with only the help of lepton number.

CMB ANISOTROPIES REVEAL QUANTIZED GRAVITY

A novel primordial spectrum with a dynamical scale of quantum gravity origin is proposed to explain the sharp fall off of the angular power spectra at low multipoles in the COBE and WMAP observations. The spectrum is derived from quantum fluctuations of the scalar curvature in a renormalizable model of induced gravity. This model describes the very early universe by the conformal field fluctuating about an inflationary background with the expansion time constant of order of the Planck mass.