Search

We study the production of gravitational waves from primordial scalar perturbations in double-inflection-point inflation, in which one of the inflection points predicts the power spectra consistent with CMB observations at large scales and the other generates a large peak in the power spectrum of scalar perturbations at small scales. We find that the reduced gravitational waves at low frequencies can be detected by future space-based laser interferometers., Comment: 15 pages, 4 figures

For the $n-1$ dimensional FRW domain wall universe induced by $n$ dimensional charged dilaton black hole, its movement formula in the bulk can be rewrite as the expansion or collapsing of domain wall. By analysing, we found that in this static AdS space, the cosmologic behaviour of domain wall is particularly single. Even more surprising, it exists an anomaly that the domain wall has a motion area outside of horizon, in which it cannot be explained by our classical theory., Comment: 6 pages, 10figures

Recently it was shown that cosmic anisotropy can be well tested using either standard siren measurement of luminosity distance $d_\mathrm{L}(z)$ from gravitational-wave (GW) observation or dispersion measure ($\mathrm{DM}(z)$) from fast radio burst (FRB). It was also observed that the combined measurement of $d_\mathrm{L}(z)\cdot\mathrm{DM}(z)$ from the GW/FRB association system as suggested in some of FRB models is more effective to constrain cosmological parameters than $d_\mathrm{L}(z)$ or $\mathrm{DM}(z)$ separately due to its independence from Hubble constant. In this paper, we will show both theoretically and with simulation that, this upgraded sirens from combined GW/FRB observations could test cosmic anisotropy with a double relative sensitivity compared to the usual standard siren from GW observation alone., Comment: 11 pages and 1 figure; match the publication version of JCAP

In this paper we study the dynamics of $ n-1$ dimensional domain wall universe embedded in a $n$ dimensional charged dilaton black hole bulk with the non-asymptotically flat and non-asymptotically (A)dS characters. We find that domain wall can always cross horizon, for which the dilaton coupling constant $a$ and the ratio of pressure to density $w$ play the role of controlling parameters. Then the consequent domain wall motion outside the black hole generally falls into four situations: all time accelerating expansion, slow expansion with a constant speed, expansion followed by collapsing into horizon, and accelerating collapsing into horizon. However, there exists a small patch of parametric sphere, in which the domain wall expansion first slows down and then accelerates. Our analysis also reveals that the big bang theory applies to the domain wall world scenario, while big bounce will not appear in our paper. Furthermore, we find that when we choose the expansion stage as radiation or matter stage, the resultant coupling strength between dilaton field and Maxwell field depends on the different black hole models., Comment: 16 pages, 15 figures

Using ideas from the brane world cosmological perturbation theory, we make linear stability analysis of dynamic thin shell wormholes constructed by cutting-and-pasting two building-block spacetime at arbitrary joining shell radiuses. We observed that in appropriate parameter choices, dynamical thin shell wormholes following from such a cut-and-paste procedure can be kept stable during the whole evolution process towards the final extreme point on which the joining-shell radius arrives on static values. Our work forms a valuable complementarity to previous analysis basing on virtual radial perturbations around the born-static value of the joining-shell radius which allows no real evolution of the wormhole., Comment: version to appear in JCAP, https://doi.org/10.1088/1475-7516/2019/03/016