Search for primordial symmetry breakings in CMB

2016 ◽  
Vol 31 (21) ◽  
pp. 1640003 ◽  
Author(s):  
Maresuke Shiraishi

There are possibilities to violate symmetries (e.g. parity and rotational invariance) in the primordial cosmological fluctuations. Such symmetry breakings can imprint very rich signatures in late-time phenomena, which may be possible to observe. Especially, Cosmic Microwave Background (CMB) will change its face drastically, corresponding to the symmetry-breaking types, since the harmonic-space representation is very sensitive to the statistical, spin and angular dependences of cosmological perturbations. Here, we discuss (1) general responses of CMB to the symmetry breakings, (2) some theoretical models creating interesting CMB signatures, and (3) aspects of the estimation from observational data.

2002 ◽  
Vol 17 (25) ◽  
pp. 3663-3680 ◽  
Author(s):  
ROBERT H. BRANDENBERGER ◽  
JÉRÔME MARTIN

Following a self-contained review of the basics of the theory of cosmological perturbations, we discuss why the conclusions reached in the recent paper by Kaloper et al.1 are too pessimistic estimates of the amplitude of possible imprints of trans-Planckian (string) physics on the spectrum of cosmic microwave anisotropies in an inflationary universe. It is shown that the likely origin of large trans-Planckian effects on late time cosmological fluctuations comes from nonadiabatic evolution of the state of fluctuations while the wavelength is smaller than the Planck (string) scale, resulting in an excited state at the time that the wavelength crosses the Hubble radius during inflation.


2009 ◽  
Vol 24 (05) ◽  
pp. 369-376 ◽  
Author(s):  
LIXIN XU ◽  
JIANBO LU

In this paper, a parametrized deceleration parameter q(a) = q0+q1(1-a) is constrained by using the current cosmic observational data from type Ia Supernova (Sne Ia) and Cosmic Microwave Background Radiation (CMB). When the CMB dataset is added as a strong constraint, it is found that the 1σ error is largely reduced. The values of transition redshift zT from decelerated expansion to accelerated expansion and current deceleration parameter q0 are larger than that obtained from the case where Sne Ia dataset is used alone. With comparison to the case of Sne Ia 182 dataset used,15 it is found that the value of transition redshift is smaller than that in Sne 192 dataset case. This is the so-called dataset dependence.


2005 ◽  
Vol 94 (11) ◽  
Author(s):  
Z. Chacko ◽  
Lawrence J. Hall ◽  
Steven J. Oliver ◽  
Maxim Perelstein

2007 ◽  
Vol 16 (05) ◽  
pp. 1571-1582
Author(s):  
SHIGEKI MATSUMOTO ◽  
JOE SATO ◽  
MASATO YAMANAKA ◽  
MASATO SENAMI

Universal extra dimension (UED) models with right-handed neutrinos are studied. The introduction of the neutrinos makes us possible not only to describe Dirac neutrino masses but also to solve the cosmological problem called the KK graviton problem. This problem is essentially caused by the late time decay of a KK photon into a KK graviton and a photon, and it distorts the spectrum of the cosmic microwave background or the diffuse photon. We point out that, once we introduce right-handed neutrinos to UED models, the KK photon decays dominantly into neutrinos and does not emit a photon. We also discuss sub-dominant modes with a photon in the decay quantitatively, and show that their branching ratios are so small that the spectra are not distorted.


2012 ◽  
Vol 21 (02) ◽  
pp. 1250017 ◽  
Author(s):  
BARUN KUMAR PAL ◽  
SUPRATIK PAL ◽  
B. BASU

We study cosmological perturbations and observational aspects for mutated hilltop model of inflation. Employing mostly analytical treatment, we evaluate observable parameters during inflation as well as post-inflationary perturbations. This further leads to exploring observational aspects related to cosmic microwave background (CMB) radiation. This semi-analytical treatment reduces complications related to numerical computation to some extent for studying the different phenomena related to CMB angular power spectrum for mutated hilltop inflation.


2011 ◽  
Vol 20 (10) ◽  
pp. 2121-2124
Author(s):  
JIAN-HUA HE ◽  
BIN WANG

In this review, we study the signature of the interaction between dark energy (DE) and dark matter (DM) on the large-scale CMB anisotropies. We find the interaction has significant influence on the late time Integrated Sachs Wolfe effect (ISW). The positive coupling could suppress the low-l part of the power spectra. We also confront the interacting models with WMAP 5-year as well as other data sets. We find that these models are well-fitted and in 1σ range, the constrained coupling between dark sectors can solve the coincidence problem.


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