Relating the inhomogeneous power spectrum to the CMB hemispherical anisotropy

Rath, Pranati K.; Aluri, Pavan K.; Jain, Pankaj

doi:10.1103/physrevd.91.023515

Cited by 18 publications

(32 citation statements)

References 65 publications

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“…It is possible to find a power spectrum based on an inhomogeneous model [3,17,32,[54][55][56] which is consistent [57] with the observed temperature anisotropy. However, it is not clear how an anisotropic model might lead to a dipole modulation.…”

Section: Introductionmentioning

confidence: 63%

“…As mentioned earlier this is denoted S data H (L). The procedure used for this calculation is the same as that followed in [14,57]. The main steps in this calculation are given below.…”

Section: Discussionmentioning

confidence: 99%

“…However, it is not clear how an anisotropic model might lead to a dipole modulation. The simplest model that one might construct leads to quadrupolar and not dipolar modulation [57]. The basic problem can be understood by considering the two point correlations in real space.…”

Section: Introductionmentioning

confidence: 99%

“…In [57], we have determined the power spectrum corresponding to an inhomogeneous model and shown that its spectral index is consistent with zero. In the present paper we determine the power spectrum of an anisotropic model based on noncommutative space-time.…”

Section: Introductionmentioning

confidence: 99%

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Noncommutative geometry and the primordial dipolar imaginary power spectrum

Jain

Rath

2015

Eur. Phys. J. C

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We argue that noncommutative space-times lead to an anisotropic dipolar imaginary primordial power spectrum. We define a new product rule, which allows us to consistently extract the power spectrum in such space-times. The precise nature of the power spectrum depends on the model of noncommutative geometry. We assume a simple dipolar model which has a power dependence on the wave number, k, with a spectral index, α. We show that such a spectrum provides a good description of the observed dipole modulation in the cosmic microwave background radiation (CMBR) data with α ≈ 0. We extract the parameters of this model from the data. The dipole modulation is related to the observed hemispherical anisotropy in the CMBR data, which might represent the first signature of quantum gravity.

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Section: Introductionmentioning

confidence: 63%

“…As mentioned earlier this is denoted S data H (L). The procedure used for this calculation is the same as that followed in [14,57]. The main steps in this calculation are given below.…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Noncommutative geometry and the primordial dipolar imaginary power spectrum

Jain

Rath

2015

Eur. Phys. J. C

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“…Such a structure is required in order that it yield an acceptable CMB temperature anisotropy pattern. It has been argued that this might provide an explanation of the observed hemispherical anisotropy [21][22][23][24][25][26][27][28][29] or equivalently the dipole modulation [30][31][32][33][34][35] of CMB temperature. Our results show that it is possible to explain the hemispherical anisotropy in terms of noncommutative space-time.…”

Section: Resultsmentioning

confidence: 99%

Cosmological power spectrum in a noncommutative spacetime

2016

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We propose a generalized star product which deviates from the standard product when the fields at evaluated at different space-time points. This produces no changes in the standard Lagrangian density in noncommutative space-time but produces a change in the cosmological power spectrum. We show that the generalized star product leads to physically consistent results and can fit the observed data on hemispherical anisotropy in the cosmic microwave background radiation.

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Probing Statistical Isotropy of Cosmological Radio Sources using Square Kilometre Array

et al. 2016

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There currently exist many observations which are not consistent with the cosmological principle. We review these observations with a particular emphasis on those relevant for Square Kilometre Array (SKA). In particular, several different data sets indicate a preferred direction pointing approximately towards the Virgo cluster. We also observe a hemispherical anisotropy in the Cosmic Microwave Background Radiation (CMBR) temperature fluctuations. Although these inconsistencies may be attributed to systematic effects, there remains the possibility that they indicate new physics and various theories have been proposed to explain them. One possibility, which we discuss in this review, is the generation of perturbation modes during the early pre-inflationary epoch, when the Universe may not obey the cosmological principle. Better measurements will provide better constraints on these theories. In particular, we propose measurement of the dipole in number counts, sky brightness, polarized flux and polarization orientations of radio sources. We also suggest test of alignment of linear polarizations of sources as a function of their relative separation. Finally we propose measurement of hemispherical anisotropy or equivalently dipole modulation in radio sources.

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Relating the inhomogeneous power spectrum to the CMB hemispherical anisotropy

Cited by 18 publications

References 65 publications

Noncommutative geometry and the primordial dipolar imaginary power spectrum

Noncommutative geometry and the primordial dipolar imaginary power spectrum

Cosmological power spectrum in a noncommutative spacetime

Probing Statistical Isotropy of Cosmological Radio Sources using Square Kilometre Array

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