Search Publications
A new parametrization for dark energy density and future deceleration
Mamon, Abdulla Al
In this work, we have proposed a general dark energy density parametrization to study the evolution of the universe. We have also constrained the model parameters using the combination of Type Ia supernova (SNIa), baryonic acoustic oscillations (BAO), cosmic microwave background radiation (CMB) and observational H(z) datasets. For the H(z) dataset…
Low-ℓ CMB from string-scale SUSY breaking?
Sagnotti, A.
Models of inflation are instructive playgrounds for supersymmetry (SUSY) breaking in Supergravity and String Theory. In particular, combinations of branes and orientifolds that are not mutually BPS can lead to brane SUSY breaking, a phenomenon where nonlinear realizations are accompanied, in tachyon-free vacua, by the emergence of steep exponentia…
A string-inspired model for the low-ℓ CMB
Sagnotti, A.; Kitazawa, N.
We present a semi-analytic exploration of some low-ℓ angular power spectra inspired by “brane supersymmetry breaking (BSB)”. This mechanism splits Bose and Fermi excitations in string theory, leaving behind an exponential potential that is just too steep for the inflaton to emerge from the initial singularity while descending it. As a result, the …
Testing isotropy of cosmos with WMAP and PLANCK data
Rath, Pranati K.; Samal, Pramoda Kumar
In recent years, there have been a large number of studies which support violation of statistical isotropy. Meanwhile, there are some studies which also found inconsistency. We use the power tensor method defined earlier in the literature to study the new CMBR data. The orientation of these three orthogonal vectors, as well as the power associated…
On the detection of point sources in Planck LFI 70 GHz CMB maps based on cleaned K-map
Kashin, A. L.; Khachatryan, H. G.; Poghosyan, E. +1 more
We use the Planck LFI 70 GHz data to further probe point source detection technique in the sky maps of the cosmic microwave background (CMB) radiation. The method developed by Tegmark et al. for foreground reduced maps and the Kolmogorov parameter as the descriptor are adopted for the analysis of Planck satellite CMB temperature data. Most of the …
The tilt of primordial gravitational waves spectra from BICEP2
Cheng, Cheng; Huang, Qing-Guo
In this paper we constrain the tilt of the spectrum of primordial gravitational waves from Background Imaging of Cosmic Extragalactic Polarization (BICEP2) data only. We find r = 0.21-0.10+0.04 and nt = -0.06-0.23+0.25 (at 68% C.L.) which implies that a scale-invariant primordial gravitational…
Take up the challenge for a single field inflation after BICEP2
Feng, Chao-Jun; Li, Xin-Zhou
The measurement of the tensor-to-scalar ratio r shows a very powerful constraint to theoretical inflation models through the detection of B-mode. In this paper, we propose a single inflation model with infinity power series potential called the Infinity Power Series (IPS) inflation model, which is well consistent with latest observations from Plan…
Constraints on dark matter annihilation and its equation of state after Planck data
Xu, Lixin
In this paper, the annihilation of dark matter (DM) fdɛ0 with nonzero equation of state (EoS) wdm was studied by using the currently available cosmic observations which include geometric and dynamic measurements. The constrained results show they are anti-correlated and are w dm = 0.000390-0.000753<…