Cosmology of the Spinor Emergent Universe and Scale-invariant Perturbations

A nonsingular emergent universe cosmology can be realized by a nonconventional spinor field as first developed in \cite{Cai:2012yf}. We study the mechanisms of generating scale-invariant primordial power spectrum of curvature perturbation in the frame of spinor emergent universe cosmology. Particularly, we introduce a light scalar field of which the kinetic term couples to the bilinear of the spinor field. This kinetic coupling can give rise to an effective "Hubble radius" for primordial fluctuations from the scalar field to squeeze at large length scales as well as to form a nearly scale-invariant power spectrum. We study the stability of the backreaction and constrain the forms of the coupling terms. These almost scale-independent fluctuations are able to be transferred into curvature perturbation after the epoch of emergent universe through a generalized curvaton mechanism and thus can explain cosmological observations.Comment: 11 pages, 4 figure

Localization and electron-phonon interaction in disordered systems

The problem of localization of electrons in the presence of electron-phonon interaction in disordered one-dimensional system is studied. In the mean-field approximation, the electron-phonon interaction results in a distorted lattice, the Peierls instability. At the same time, a gap opens at the Fermi level in the electron band. It is known that the scattering of the electrons by the disorder will destroy the lattice distortion and close the gap. However, there is disagreement on the way this happens and on the nature of the resulting electronic states. Recent progress in the experimental and theoretical studies of the one-dimensional organic polymer systems has given a great interest in this problem, and has also provided a suitable model for comparison with the theoretical studies. In this work we present numerical results for the electron density of states, the effective size of the electronic state and the frequency dependent conductivity, and emphasize the mutual effects of the electron localization and the Peierls distortion. We also report on the development based on analytical perturbation theory, and compare some of the available results with those from the numerical studies and experiments

The Significance of the Variation Theory in Cross-Cultural Communication

In her article The Significance of the Variation Theory in Cross-Cultural Communication Yi Wan analyzes some problems that East-West Comparative Literature, as a discipline, has encountered and discusses the significance of the development of the Variation Theory, proposed by Shunqing Cao. The author aims to explore two important points of this new platform, namely, heterogeneity and variation, and compares this new perspective to the French School, which is based on influences and the American School which is based on analogies. By investigating the variations of literary texts or theories during the course of cross-civilization communication from the perspectives of imagology of Variation Theory and sinicization of western literary theory, this article posits that more attention should be given to this new paradigm of comparative literature studies. Variation Theory is based on maintaining and developing the uniqueness of different literature and cultures. It strives to see literature in the light of the culture it was created in, free of the paradigms of the culture it is being shared with

Cosmological constraints from Radial Baryon Acoustic Oscillation measurements and Observational Hubble data

We use the Radial Baryon Acoustic Oscillation (RBAO) measurements, distant type Ia supernovae (SNe Ia), the observational $H(z)$ data (OHD) and the Cosmic Microwave Background (CMB) shift parameter data to constrain cosmological parameters of $\Lambda$CDM and XCDM cosmologies and further examine the role of OHD and SNe Ia data in cosmological constraints. We marginalize the likelihood function over $h$ by integrating the probability density $P\propto e^{-\chi^{2}/2}$ to obtain the best fitting results and the confidence regions in the $\Omega_{m}-\Omega_{\Lambda}$ plane.With the combination analysis for both of the {\rm $\Lambda$}CDM and XCDM models, we find that the confidence regions of 68.3%, 95.4% and 99.7% levels using OHD+RBAO+CMB data are in good agreement with that of SNe Ia+RBAO+CMB data which is consistent with the result of Lin et al's work. With more data of OHD, we can probably constrain the cosmological parameters using OHD data instead of SNe Ia data in the future.Comment: 8 pages, 6 figures, 2 tables, accepted for publication in Physics Letters

Imprints of Schwinger Effect on Primordial Spectra

We study the Schwinger effect during inflation and its imprints on the primordial power spectrum and bispectrum. The produced charged particles by Schwinger effect during inflation can leave a unique angular dependence on the primordial spectra.Comment: 27 pages, 13 figures, JHEP accepted versio