6,824 research outputs found
Inflation with High Derivative Couplings
We study a class of generalized inflation models in which the inflaton is
coupled to the Ricci scalar by a general term. The scalar power
spectrum, the spectral index, the running of the spectral index, the tensor
mode spectrum and a new consistency relation of the model are calculated. We
discuss in detail the issues of how to diagonize the coupled perturbation
equations, how to deal with an entropy-like source, and how to determine the
initial condition by quantization. By studying some explicit models, we find
that rich phenomena such as a blue scalar power spectrum, a large running of
the spectral index, and a blue tensor mode spectrum can be obtained.Comment: 26 pages, LaTeX; v2: refs. added; refs. correcte
Inflation with Holographic Dark Energy
We investigate the corrections of the holographic dark energy to inflation
paradigm. We study the evolution of the holographic dark energy in the
inflationary universe in detail, and carry out a model-independent analysis on
the holographic dark energy correction to the primordial scalar power spectrum.
It turns out that the corrections generically make the spectrum redder. To be
consistent with the experimental data, there must be a upper bound on the
reheating temperature. We also discuss the corrections due to different choices
of the infrared cutoff.Comment: 15 pages, 3 figures, v2: references added, a fast-roll discussion
added. v3: typos corrected. v4: final version to appear in NP
General Single Field Inflation with Large Positive Non-Gaussianity
Recent analysis of the WMAP three year data suggests
in the WMAP convention. It is necessary to make sure
whether general single field inflation can produce a large positive
before turning to other scenarios. We give some examples to generate a large
positive in general single field inflation. Our models are
different from ghost inflation. Due to the appearance of non-conventional
kinetic terms, can be realized in single field inflation.Comment: 27 pages, 3 figure; final version published in JCA
K-essence Explains a Lorentz Violation Experiment
Recently, a state of the art experiment shows evidence for Lorentz violation
in the gravitational sector. To explain this experiment, we investigate a
spontaneous Lorentz violation scenario with a generalized scalar field. We find
that when the scalar field is nonminimally coupled to gravity, the Lorentz
violation induces a deformation in the Newtonian potential along the direction
of Lorentz violation.Comment: 8 pages, the final version, discussion and references adde
- …