相关论文: Red Density Perturbations and Inflationary Gravita…
In this paper, we investigate scalar-induced gravitational waves (GWs) generated in the post-inflationary universe to infer new limits on warm inflation. We specifically examine the evolution of primordial GWs by scalar perturbations…
We show that the recently reported cosmic gravitational wave background by the NANOGrav 15-year collaboration may be the result of resonant particle creation during inflation. For the appropriate amplitude and particle mass an enhancement…
Stochastic gravitational waves can be induced from the primordial curvature perturbations generated during inflation, through scalar-tensor mode coupling at the second order of cosmological perturbation theory. Here we discuss a model of…
Bursts of particle production during inflation provide a well-motivated mechanism for creating bump like features in the primordial power spectrum. Current data constrains these features to be less than about 5% the size of the featureless…
We quantify the limiting factors in optimizing current-technology cosmic microwave background (CMB) polarization experiments in order to learn about inflationary physics. We consider space-based, balloon-borne and ground-based experiments.…
The curvaton and the inhomogeneous reheating scenarios for the generation of the cosmological curvature perturbation on large scales represent an alternative to the standard slow-roll scenario where the observed density perturbations are…
Inflation is studied in the context of induced gravity (IG) $\gamma \sigma^2 R$, where $R$ is the Ricci scalar, $\sigma$ a scalar field and $\gamma$ a dimensionless constant. We study in detail cosmological perturbations in IG and examine…
Primordial gravitational waves (GWs) with frequencies > 10^{-15} Hz contribute to the radiation density of the Universe at the time of decoupling of the cosmic microwave background (CMB). The effects of this GW background on the CMB and…
We present a novel mechanism for gravitational wave generation in the early Universe. Light spectator scalar fields during inflation can acquire a blue-tilted power spectrum due to stochastic effects. We show that this effect can lead to…
Asteroseismology probes the interiors of stars by studying oscillation modes at a star's surface. Although pulsation spectra are well understood for solar-like oscillators, a substantial fraction of red giant stars observed by Kepler…
Assuming that inflation is succeeded by a phase of matter domination, which corresponds to a low temperature of reheating $T_r<10^9\rm{GeV}$, we evaluate the spectra of gravitational waves induced in the post-inflationary universe. We work…
We study the possibility that particle production during inflation could source observable gravity waves on scales relevant for Cosmic Microwave Background experiments. A crucial constraint on such scenarios arises because particle…
We propose a non-Gaussianity test for gravitational wave backgrounds by combining data streams of multiple detectors. This simple method allows us to check whether a detected background is "smooth" enough to be consistent with an…
The relic gravitational wave (RGW) generated during the inflation depends on the initial condition via the amplitude, the spectral index $n_t$ and the running index $\alpha_t$. CMB observations so far have only constrained the tensor-scalar…
We study gravitational wave production in an expanding Universe during the first stages following inflation, and investigate the consequences of the Gauss-Bonnet term on the inflationary parameters for a power-law inflation model with a GB…
Cosmological perturbations, originating in the quantum fluctuations of the fields that drive inflation, are observed to be nearly scale invariant at the largest scales. At smaller scales, however, perturbations are not severely constrained…
We summarize the utility of precise cosmic microwave background (CMB) polarization measurements as probes of the physics of inflation. We focus on the prospects for using CMB measurements to differentiate various inflationary mechanisms. In…
Recent observations by pulsar timing arrays (PTAs) indicate a potential detection of a stochastic gravitational wave (GW) background. Metastable cosmic strings have been recognized as a possible source of the observed signals. In this…
During or towards the end of inflation, the Standard Model (SM) Higgs forms a condensate with a large amplitude. Following inflation, the condensate oscillates, decaying non-perturbatively into the rest of the SM species. The resulting…
We present a supergravity inflationary scenario in which the inflaton field takes values considerably larger than the Planck scale. It is based on a class of inflationary potentials which can be derived from ``singular'' Kaehler potentials…