Ya-Bo Wu

More on QCD ghost dark energy

The difference between the vacuum energy of quantum fields in Minkowski space and in a Friedmann-Robertson-Walker universe might be related to the observed dark energy. The vacuum energy of the Veneziano ghost field introduced to solve the U(1)(A) problem in QCD is of the form H + O(H-2). Based on this, we study the dynamical evolution of a phenomenological dark energy model whose energy density is of the form alpha H + beta H-2. In this model, the universe approaches a de Sitter phase at late times. We fit the model with current observational data, including SnIa, BAO, CMB, BBN, the Hubble parameter, and the growth rate of matter perturbation. It shows that the universe begins to accelerate at redshift z similar to 0.75, and this model is consistent with current data. In particular, this model fits the data of the growth factor well as the Lambda CDM model.

Energy conditions and stability in generalized f(R) gravity with arbitrary coupling between matter and geometry

Abstract The energy conditions and the Dolgov–Kawasaki criterion in generalized f ( R ) gravity with arbitrary coupling between matter and geometry are derived in this Letter, which are quite general and can degenerate to the well-known energy conditions in GR and f ( R ) gravity with non-minimal coupling and non-coupling as special cases. In order to get some insight on the meaning of these energy conditions and the Dolgov–Kawasaki criterion, we apply them to a class of models in the FRW cosmology and give some corresponding results.

Constraints on a decomposed dark fluid with constant adiabatic sound speed by jointing the geometry test and growth rate after Planck data

In this paper, a unified dark fluid with constant adiabatic sound speed is decomposed into cold dark matter interacting with vacuum energy. Based on a Markov-chain Monte Carlo method, we constrain this model by jointing the geometry and dynamical measurement. The geometry test includes cosmic microwave background radiation from Planck, baryon acoustic oscillation, and type-Ia supernovae; the dynamic measurement is

Modified f ( G ) gravity models with curvature–matter coupling

f{\ensuremath{\sigma}}_{8}(z)

Magnetic-field effects on p-wave phase transition in Gauss–Bonnet gravity

data points, which is obtained from the growth rate via redshift space distortion, and

Lifshitz effects on holographic p-wave superfluid

{\ensuremath{\sigma}}_{8}(z)

Lifshitz effects on vector condensate induced by a magnetic field

is the root-mean-square amplitude of the density contrast

Reconstruction of new holographic scalar field models of dark energy in Brans-Dicke universe

\ensuremath{\delta}

Five-dimensional generalized f(R) gravity with curvature–matter coupling

at the comoving

COSMOLOGICAL EVOLUTION OF MODIFIED CHAPLYGIN GAS INTERACTING WITH BAROTROPIC BACKGROUND FLUID

8{h}^{\ensuremath{-}1}\text{ }\text{ }\mathrm{Mpc}