分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-09-27
摘要： By using the cubic spline interpolation method, we reconstruct the shape of the primordial scalar and tensor power spectra from the recently released Planck temperature and BICEP2 polarization cosmic microwave background data. We find that the vanishing scalar index running (dns/d ln k) model is strongly disfavored at more than 3σ confidence level on the k = 0.0002 Mpc−1 scale. Furthermore, the power-law parameterization gives a blue-tilt tensor spectrum, no matter using only the first 5 bandpowers nt = 1.20+0.56 (95%CL) or the full 9 bandpowers nt = 1.24+0.51 (95%CL) of−0.64 −0.58BICEP2 data sets. Unlike the large tensor-to-scalar ratio value (r 0.20) under the scale-invariant tensor spectrum assumption, our interpolation approach gives r0.002 < 0.060 (95%CL) by using the first 5 bandpowers of BICEP2 data. After comparing the results with/without BICEP2 data, we find that Planck temperature with small tensor amplitude signals and BICEP2 polarization data with large tensor amplitude signals dominate the tensor spectrum reconstruction on the large and small scales, respectively. Hence, the resulting blue tensor tilt actually reflects the tension between Planck and BICEP2 data.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-09-27
摘要： We update the cosmological parameter estimation for three non-vanilla models by a joint analysis of CCCP X-ray cluster, the newly released Planck CMB data as well as some external data sets, such as baryon acoustic oscillation measurements from the 6dFGS, SDSS DR7 and BOSS DR9 surveys, and Hubble Space Telescope H0 measurement. First of all, we nd that X-ray cluster data sets strongly favor a non-zero summed neutrino mass at more than 3 con dence level in these non-vanilla models. And then, we reveal some tensions between X-ray cluster and Planck data in some cosmological parameters. For the matter power spectrum amplitude 8, X-ray cluster data favor a lower value compared with Planck. Because P of the strong 8 m degeneracy, this tension could beyond 2 con dence level when the P summed neutrino mass m is allowed to vary. For the CMB lensing amplitude AL, the addition of X-ray cluster data results in a 3 deviation from the vanilla model. Furthermore, Planck+X-ray data prefer a large Hubble constant and phantom-like dark energy equation of state, which are in 2 tension with those from WMAP7+X-ray data. Finally, we nd that these tensions/descrepencies could be relaxed in some sense by adding a 9% systematic shift in the cluster mass functions.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-09-27
摘要： We investigate the nucleosynthesis constraint on Lorentz invariance violation in the neutrino sector which influences the formation of light elements by altering the energy density of the Universe and weak reaction rates prior to and during the big-bang nucleosynthesis epoch. We derive the weak reaction rates in the Lorentz-violating extension of the standard model. Using measurements of the primordial helium-4 and deuterium abundances, we give a tighter constraint on the deformed parameter than that derived from measurements of the cosmic microwave background anisotropies.
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