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Related papers: Primordial Power Spectrum Reconstruction

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Recently released data from pulsar timing array (PTA) collaborations provide strong evidence for a stochastic signal consistent with a gravitational-wave background, potentially originating from scalar-induced gravitational waves (SIGWs).…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-31 Zhu Yi , Zhi-Qiang You , You Wu

A method for measuring the spectrum of a density field by a discrete wavelet space-scale decomposition (SSD) has been studied. We show how the power spectrum can effectively be described by the father function coefficients (FFC) of the…

Astrophysics · Physics 2007-05-23 Jesus Pando , Li-Zhi Fang

Motivated by recent developments in perturbative calculations of the nonlinear evolution of large-scale structure, we present an iterative algorithm to reconstruct the initial conditions in a given volume starting from the dark matter…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-01 Marcel Schmittfull , Tobias Baldauf , Matias Zaldarriaga

We present three non-parametric Bayesian primordial reconstructions using Planck 2018 polarization data: linear spline primordial power spectrum reconstructions, cubic spline inflationary potential reconstructions and sharp-featured…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-20 Will J. Handley , Anthony N. Lasenby , Hiranya V. Peiris , Michael P. Hobson

There is a large and growing interest in observations of small-scale structure in dark matter. We propose a new way to probe dark matter structures in the $\sim 10 - 10^8 \, M_\odot$ range. This allows us to constrain the primordial power…

High Energy Physics - Phenomenology · Physics 2024-10-17 Peter W. Graham , Harikrishnan Ramani

We use the localized principle component analysis to detect deviations from scale invariance of the primordial power spectrum of curvature perturbations. With the technique we make uncorrelated estimates of the primordial power spectrum…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-25 Zong-Kuan Guo , Yuan-Zhong Zhang

There has been a growing interest in wideband spectrum sensing due to its applications in cognitive radios and electronic surveillance. To overcome the sampling rate bottleneck for wideband spectrum sensing, in this paper, we study the…

Information Theory · Computer Science 2019-10-17 Linxiao Yang , Jun Fang , Huiping Duan , Hongbin Li

Features in the primordial power spectrum have been suggested as an explanation for glitches in the angular power spectrum of temperature anisotropies measured by the WMAP satellite. However, these glitches might just as well be artifacts…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-28 Jan Hamann , Arman Shafieloo , Tarun Souradeep

Measuring the deviation from scale invariance of the primordial power spectrum is a critical test of inflation. In this paper we reconstruct the shape of the primordial power spectrum of curvature perturbations from the cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-01 Zong-Kuan Guo , Dominik J. Schwarz , Yuan-Zhong Zhang

We describe a novel end-to-end approach using Machine Learning to reconstruct the power spectrum of cosmological density perturbations at high redshift from observed quasar spectra. State-of-the-art cosmological simulations of structure…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-21 Maria Han Veiga , Xi Meng , Oleg Y. Gnedin , Nickolay Y. Gnedin , Xun Huan

Primordial black holes and secondary gravitational waves can be used to probe the small scale physics at very early time. For secondary gravitational waves produced after the horizon reentry, we derive an analytical formula for the time…

General Relativity and Quantum Cosmology · Physics 2019-12-25 Yizhou Lu , Yungui Gong , Zhu Yi , Fengge Zhang

We present a novel approach to the regression of quantum mechanical energies based on a scattering transform of an intermediate electron density representation. A scattering transform is a deep convolution network computed with a cascade of…

Machine Learning · Computer Science 2016-05-23 Matthew Hirn , Nicolas Poilvert , Stéphane Mallat

We show that the energy density spectrum of the primordial gravitational waves has characteristic features due to the successive changes in the relativistic degrees of freedom during the radiation era. These changes make the evolution of…

Astrophysics · Physics 2009-11-11 Yuki Watanabe , Eiichiro Komatsu

The primordial matter power spectrum quantifies fluctuations in the distribution of dark matter immediately following inflation. Over cosmic time, over-dense regions of the primordial density field grow and collapse into dark matter halos,…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-30 Daniel Gilman , Andrew Benson , Jo Bovy , Simon Birrer , Tommaso Treu , Anna Nierenberg

We develop a maximum likelihood based method of reconstructing band powers of the density and velocity power spectra at each wavenumber bins from the measured clustering features of galaxies in redshift space, including marginalization over…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Jiayu Tang , Issha Kayo , Masahiro Takada

By using the cubic spline interpolation method, we reconstruct the shape of the primordial scalar and tensor power spectra from the recently released {\it Planck} temperature and BICEP2 polarization cosmic microwave background data. We find…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-06 Bin Hu , Jian-Wei Hu , Zong-Kuan Guo , Rong-Gen Cai

We discuss a method for a model independent reconstruction of the CMB temperature fluctuation power spectrum on small and intermediate scales that is geared to individual experiments. The importance of off-diagonal correlations for…

Astrophysics · Physics 2009-09-25 Martin White

We introduce an algorithm of joint approximation of a function and its first derivative by alternative orthogonal polynomials on the interval [0,1].The algorithm exhibits properties of shape preserving approximation for the function. A weak…

Numerical Analysis · Mathematics 2020-01-14 Vladimir S. Chelyshkov

One of the main goals of modern observational cosmology is to map the large scale structure of the Universe. A potentially powerful approach for doing this would be to exploit three-dimensional spectral maps, i.e. the specific intensity of…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-18 Roland de Putter , Gilbert P. Holder , Tzu-Ching Chang , Olivier Dore

I present a new approach to recover the primordial density fluctuations and the cosmic web structure underlying a galaxy distribution. The method is based on sampling Gaussian fields which are compatible with a galaxy distribution and a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Francisco-Shu Kitaura