Forecasting sensitivity on tilt of power spectrum of primordial gravitational waves after Planck satellite

Huang, Qing-Guo; Wang, Sai; Zhao, Wen

doi:10.1088/1475-7516/2015/10/035

Cited by 31 publications

(38 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…According to the results of Calabrese et al (2017), future constraints from S4 experiment for a CMB signal with a tensorto-scalar ratio r ≃ 10 −3 will have a sensitivity level of σ r ≃ 5 × 10 −4 and the combination of PIXIE and S4 will enable a 5σ detection of r if larger than 2 × 10 −3 . Similar results where reported by Huang et al (2015) for different future planned CMB satellite experiments. Since, for V 2 (φ) inflation we find r ≃ 10 −3 , future experiments should allow us to differentiate it from normal inflation and possibly from the quadratic inflation V 1 (φ) which predict much smaller value of r. Moreover, Huang et al (2015) also showed that the CMB signal of tensor-to-scalar r ≃ 2 × 10 −3 will provide sensitivity level of σ nt ≃ 0.1 on tensor spectral tilt.…”

Section: Resultssupporting

confidence: 90%

Confronting phantom inflation with Planck data

Iqbal

Malik

Qureshi

2018

Astrophys Space Sci

View full text Add to dashboard Cite

The latest Planck results are in excellent agreement with the theoretical expectations predicted from standard normal inflation based on slow-roll approximation which assumes equation-of-state ω ≥ −1.In this work, we study the phantom inflation (ω < −1) as an alternative cosmological model within the slow-climb approximation using two hybrid inflationary fields. We perform Chain Monte Carlo analysis to determine the posterior distribution and best fit values for the cosmological parameters using Planck data and show that current CMB data does not discriminate between normal and phantom inflation. Interestingly, unlike in normal inflation, ω in phantom induced inflation evolves very slowly away from −1 during the inflation. Furthermore, in contrast to the standard normal inflation for which only upper bound on tensor-to-scalar ratio r are possible, we obtain both upper and lower bounds for the two hybrid fields in the phantom scenario. Finally, we discuss prospects of future high precision polarization measurements and show that it may be possible to establish the dominance of one model over the other.

show abstract

Section: Resultssupporting

confidence: 90%

Confronting phantom inflation with Planck data

Iqbal

Malik

Qureshi

2018

Astrophys Space Sci

View full text Add to dashboard Cite

show abstract

“…Our results will have important implications following the detection of non-zero tensor-to-scalar ratio by a future CMB experiment (e.g., see Ref. [77] 3 and references therein). Such a detection, together with the data from PTAs and ground-based interferometers will put very tight limits on n t , with larger values of r being the most constraining.…”

Section: B Comparison With Theorymentioning

confidence: 78%

Gravitational-Wave Cosmology across 29 Decades in Frequency

Lasky¹,

Mingarelli²,

Smith³

et al. 2016

Phys. Rev. X

181

183

View full text Add to dashboard Cite

Quantum fluctuations of the gravitational field in the early Universe, amplified by inflation, produce a primordial gravitational-wave background across a broad frequency band. We derive constraints on the spectrum of this gravitational radiation, and hence on theories of the early Universe, by combining experiments that cover 29 orders of magnitude in frequency. These include Planck observations of cosmic microwave background temperature and polarization power spectra and lensing, together with baryon acoustic oscillations and big bang nucleosynthesis measurements, as well as new pulsar timing array and ground-based interferometer limits. While individual experiments constrain the gravitational-wave energy density in specific frequency bands, the combination of experiments allows us to constrain cosmological parameters, including the inflationary spectral index n t and the tensor-to-scalar ratio r. Results from individual experiments include the most stringent nanohertz limit of the primordial background to date from the Parkes Pulsar Timing Array, Ω GW ðfÞ < 2.3 × 10 −10 . Observations of the cosmic microwave background alone limit the gravitational-wave spectral index at 95% confidence to n t ≲ 5 for a tensor-toscalar ratio of r ¼ 0.11. However, the combination of all the above experiments limits n t < 0.36. Future * paul.lasky@monash.eduPublished by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.PHYSICAL REVIEW X 6, 011035 (2016) 2160-3308=16=6(1)=011035 (11) 011035-1 Published by the American Physical Society Advanced LIGO observations are expected to further constrain n t < 0.34 by 2020. When cosmic microwave background experiments detect a nonzero r, our results will imply even more stringent constraints on n t and, hence, theories of the early Universe.

show abstract

“…Therefore, using Eqs. (16) and (17) could not constrain the parameter β. Actually, the parameter β of the IR DBI model can be well constrained by the primordial non-Gaussianities.…”

Section: Models and Methodologymentioning

confidence: 99%

Constraints on brane inflation after Planck 2015: Impacts of the latest local measurement of the Hubble constant

Guo

Zhang

et al. 2018

Sci. China Phys. Mech. Astron.

View full text Add to dashboard Cite

We investigate the observational constraints on three typical brane inflation models by considering the latest local measurement of the Hubble constant in the global fit. We also employ other observational data, including the Planck 2015 CMB data, the BICEP2/Keck Array B-mode data, and the baryon acoustic oscillations data, in our analysis. Previous studies have shown that the addition of the latest local H0 measurement favors a larger spectral index, and can exert a significant influence on the model selection of inflation. In this work, we investigate its impacts on the status of brane inflation models. We find that, when the direct H0 measurement is considered, the prototype model of brane inflation is still in good agreement with the current observational data within the 2σ level range. For the KKLMMT model, the consideration of the H0 measurement allows the range of the parameter β to be amplified to O(10 −2 ), which slightly alleviates the fine-tuning problem.For the IR DBI model, the addition of the H0 measurement does not provide a better fit. These results show that the consideration of the new H0 prior can exert a considerable influence on the brane inflation models. At last, we show that, when β 1.1, the equilateral non-Gaussianity in the IR DBI inflation model is compatible with the current CMB data at the 1σ level.

show abstract

Forecasting sensitivity on tilt of power spectrum of primordial gravitational waves after Planck satellite

Cited by 31 publications

References 55 publications

Confronting phantom inflation with Planck data

Confronting phantom inflation with Planck data

Gravitational-Wave Cosmology across 29 Decades in Frequency

Constraints on brane inflation after Planck 2015: Impacts of the latest local measurement of the Hubble constant

Contact Info

Product

Resources

About