118515319
Reconstructing the local potential of inflation with BICEP2 data
We locally reconstruct the inflationary potential by using the current constraints on r and n(s) from BICEP2 data. Assuming small and negligible alpha(s), the inflationary potential is approximately linear in Delta phi similar to M-pl range but becomes non-linear in Delta phi similar to 10M(pl) range. However if we vary the value of alpha(s) within the range given by constraints from Planck measurement, the local reconstruction is only valid in the range of Delta phi similar to 0.4M(pl), which challenges the inflationary background from the point of view of effective field theory. We show that, within the range of Delta phi similar to 0.4M(pl), the inflation potential can be precisely reconstructed. With the current reconstruction, we show that V(phi) similar to phi(2) and phi(3) are consistent, while phi model is ruled out by 95% confidence level of the reconstructed range of potential. This sets up a strong limit of large-field inflation models.
119270914
Quadra-Spectrum and Quint-Spectrum from Inflation and Curvaton Models
We calculate the quadra-spectrum and quint-spectrum, corresponding to five and six point correlation functions of the curvature perturbation. For single field inflation with standard kinetic term, the quadra-spectrum and quint-spectrum are small, which are suppressed by slow roll parameters. The calculation can be generalized to multiple fields. When there is no entropy perturbation, the quadra-spectrum and quint-spectrum are suppressed as well. With the presence of entropy perturbation, the quadra-spectrum and quint-spectrum can get boosted. We illustrate this boost in the multi-brid inflation model. For the curvaton scenario, the quadra-spectrum and quint-spectrum are also large in the small r limit. We also calculate representative terms of quadra-spectrum and quint-spectrum for inflation with generalized kinetic terms, and estimate their order of magnitude for quasi-single field inflation.
118533325
Quasi-Single Field Inflation and Non-Gaussianities
In quasi-single field inflation models, massive isocurvature modes, that are coupled to the inflaton and have mass of order the Hubble parameter, can have nontrivial impacts on density perturbations, especially non-Gaussianities. We study a simple example of quasi-single field inflation in terms of turning inflaton trajectory. Large bispectra with a one-parameter family of novel shapes arise, lying between the well-known local and equilateral shape. The trispectra can also be very large and its magnitude tNL can be much larger than fNL2.
119104249
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.
17457342
Curvaton dynamics and the non-linearity parameters in the curvaton model
We investigate the curvaton dynamics and the non-linearity parameters in the curvaton model with a potential slightly deviating from the quadratic form in detail. The non-linearity parameter gNL will show up due to the curvaton self-interaction. We also point out that the leading order of the non-quadratic term in the curvaton potential can be negative, for example in the axion-type curvaton model. If a large positive gNL is detected, the axion-type curvaton model will be preferred.
44351609
A no-go theorem for generalized vector Galileons on flat spacetime
A bstractWe explore the possibility for generalized electromagnetism on flat spacetime. For a single copy of U(1) gauge theory, we show that the Galileon-type generalization of electromagnetism is forbidden. Given that the equations of motion for the vector field are gauge invariant and Lorentz invariant, follow from an action and contain no more than second derivative on Aμ, the equations of motion are at most linear with respect to second derivative of Aμ.
3254210
Implications of Cosmic Microwave Background Anisotropies for Large-Scale Variations in Hubble's Constant
Low-amplitude (linear regime) cosmic density fluctuations lead to spatial variations in the locally measurable value of H0 (denoted as HL), δH ≡ (HL - H0)/H0, which are of order 3%-6% (95% confidence interval) in a sphere of 200 h-1 Mpc in diameter, and of order 1%-2% in a sphere of 400 h-1 Mpc in diameter, for three currently viable structure formation models (tilted cold dark matter [CDM], ΛCDM, and open CDM) as normalized by the 4 yr COBE DMR data. However, the true matter distribution power spectrum may differ from any of the current viable models. For example, it may contain sharp features which have escaped detection so far. The measured cosmic microwave background (CMB) dipole velocity (the Galaxy's peculiar velocity with respect to the CMB rest frame) provides additional constraints on the probability distribution of δH that supplement our limited knowledge of the power spectrum. For a matter power spectrum that consists of the smooth power spectrum of a viable cosmological model plus a δ-function bump, we find that given the CMB dipole velocity, the 95% confidence level (CL) upper limit of |δH| increases approximately by a factor of 2, but the probability distribution of δH is non-Gaussian, with increased probability at small δH compared to Gaussian. Abandoning model power spectra entirely, we find that the observed CMB dipole velocity alone provides a very robust limit, (δ2HR)-1/2 < 10.5 h-1 Mpc/R at 95% CL, in a sphere of radius R, for an arbitrary power spectrum. Thus, variations between currently available local measures of H0 and its true global value of a few to several percent are to be expected, and differences as large as 10% are possible based on our current knowledge of the CMB anisotropies.
98624315
Dynamic interactions of fast ions with multiwalled carbon nanotubes
Abstract We use a two-fluid hydrodynamic model to describe the dielectric response of the σ and π electron systems on a multiwalled carbon nanotube consisting of up to several tens of concentric cylindrical shells. In particular, we evaluate the stopping power and the dynamical image potential for ions moving parallel to the nanotube axis. It is found that both quantities are profoundly affected by the increasing number of nanotube shells, as a consequence of the rich plasmon spectra developed due to the inter- and intra-shell electrostatic interactions between the electron systems.
125493400
The sigma pole in J / psi ---> omega pi+ pi-
118409330
Unambiguous determination of the neutrino mass hierarchy using reactor neutrinos
Determination of the neutrino mass hierarchy in a reactor neutrino experiment at the medium baseline is discussed. Observation of the interference effects between the Delta m(31)(2) and Delta m(32)(2) oscillations enables a relative measurement independent of the knowledge of the absolute mass-squared difference. With a 20 kton liquid scintillator detector of the 3%/root E (MeV) energy resolution, the Daya Bay II experiment at a baseline of similar to 50 km from reactors of total thermal power 36 GW can determine the mass hierarchy at a confidence level of Delta chi(2)(MH) similar to (10 divided by 12) (3 divided by 3.5 sigma) in six years after taking into account the real spatial distribution of reactor cores. We show that the unknown residual energy nonlinearity of the liquid scintillator detector has limited impact on the sensitivity due to the self-calibration of small oscillation peaks. Furthermore, an extra increase of Delta chi(2)(MH) similar or equal to 4(9) can be obtained, by including the precise measurement of the effective mass-squared difference Delta m(mu mu)(2) of expected relative error 1.5% (1%) from ongoing long-baseline muon neutrino disappearance experiments. The sensitivities from the interference and from absolute measurements can be cross-checked. When combining these two, the mass hierarchy can be determined at a confidence level of Delta chi(2)(MH) similar to (15 divided by 20) (4 sigma) in six years.
122028642
The effect of the tensor force on the bubble structure in Ar isotopes
Abstract.The tensor force effect on the proton bubble structure of Ar isotopes is investigated in the framework of the Hartree-Fock-Bogoliubov (HFB) approach with the Skyrme interactions SLy5+T and SLy5+Tw. It is shown that the tensor force effect of the SLy5+Tw interaction favors the bubble structure of 44-56Ar due to the inversion between the proton single-particle states $ 2s_{1/2}$ and $ 1d_{3/2}$ ( $ 2s_{1/2}$ -1d3/2 inversion). However, the SLy5+T interaction cannot lead to any $ 2s_{1/2}$ -1d3/2 inversion of Ar isotopes, consequently, no bubble structure can be found in the isotopes. In addition, taking 46Ar as an example, the competition between the tensor force and pairing interaction on the bubble formation is examined in order to understand the bubble formation mechanism.