7,135 research outputs found
Suppression of long-wavelength CMB spectrum from the no-boundary initial condition
The lack of correlations at the long-wavelength scales of the cosmic
microwave background spectrum is a long-standing puzzle and it persists in the
latest Planck data. By considering the Hartle-Hawking no-boundary wave function
as the initial condition of the inflationary universe, we propose that the
power suppression can be the consequence of a massive inflaton, whose initial
vacuum is the Euclidean instanton in a compact manifold. We calculate the
primordial power spectrum of the perturbations, and find that as long as the
scalar field is moderately massive, the power spectrum is suppressed at the
long-wavelength scales.Comment: 9 pages, 7 figures; journal versio
Slow-Roll Inflation Preceded by a Topological Defect Phase \`a la Chaplygin Gas
We present a simple toy model corresponding to a network of frustrated
topological defects of domain walls or cosmic strings that exist previous to
the standard slow-roll inflationary era of the universe. Such a network (i) can
produce a slower inflationary era than that of the standard scenario if it
corresponds to a network of frustrated domain walls or (ii) can induce a
vanishing universal acceleration; i.e., the universe would expand at a constant
speed, if it corresponds to a network of frustrated cosmic strings red. Those
features are phenomenologically modeled by a Chaplygin gas that can interpolate
between a network of frustrated topological defects and a de Sitter-like or a
power-law inflationary era. We show that this scenario can alleviate the
quadruple anomaly of the cosmic microwave background spectrum. Using the method
of the Bogoliubov coefficients, we obtain the spectrum of the gravitational
waves as would be measured today for the whole range of frequencies. We comment
on the possible detection of this spectrum by the planned detectors like BBO
and DECIGO.Comment: 11 pages, 12 figures. RevTex4-1. Expanded discussion. Version
accepted in PR
Synthesis and crystal structure of the first 6a-thiathiophthen metal complex [Mo(CO)_5PPh_(2]2)(µ-C_5H_2S_3)
The first 6a-thiathiophthen metal complex was prepared by treating M(CO_)5[PPh_2CS_2CH_2C≡CH] with a catalytic amount of secondary amine or tertiary amine; the structure of the 6a-thiathiophthen molybdenum complex is confirmed by an X-ray diffraction analysis
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