Authors:Huai-Ke Guo; Kuver Sinha, Daniel Vagie Graham White First page: 001 Abstract: We undertake a careful analysis of stochastic gravitational wave production from cosmological phase
transitions in an expanding universe, studying both a standard radiation as well as a matter
dominated history. We analyze in detail the dynamics of the phase transition, including the false
vacuum fraction, bubble lifetime distribution, bubble number density, mean bubble separation, etc.,
for an expanding universe. We also study the full set of differential equations governing the
evolution of plasma and the scalar field during the phase transition and generalize results obtained
in Minkowski spacetime. In particular, we generalize the sound shell model to the expanding universe
and determine the velocity field power spectrum. This ultimately provides an accurate calculation of
the gravitational wave spectrum seen today for the dominant source of sound waves. For the amplitude
of the gravitational wave spectrum visible today, we find a suppression factor arising from the
finite ... Citation: Journal of Cosmology and Astroparticle Physics PubDate: 2021-01-04T00:00:00Z DOI: 10.1088/1475-7516/2021/01/001 Issue No:Vol. 2021, No. 01 (2021)

Authors:Francesco Montanari; Stefano Camera First page: 002 Abstract: We present a method that allows us for the first time to estimate the signal-to-noise ratio (SNR) of
the harmonic-space galaxy bispectrum induced by gravity, a complementary probe to already well
established Fourier-space clustering analyses. We show how to do it considering only ~1000 triangle
configurations in multipole space, corresponding to a computational speedup of a factor ##IMG##
[https://ej.iop.org/icons/Entities/calO.gif] {Script O} (10 2 )− ##IMG##
[https://ej.iop.org/icons/Entities/calO.gif] {Script O} (10 3 ), depending on the redshift bin, when
including mildly non-linear scales. Assuming observational specifications consistent with
forthcoming spectroscopic and photometric galaxy surveys like the \euc\ satellite and the Square
Kilometre Array (phase 1), we show: that ... Citation: Journal of Cosmology and Astroparticle Physics PubDate: 2021-01-04T00:00:00Z DOI: 10.1088/1475-7516/2021/01/002 Issue No:Vol. 2021, No. 01 (2021)

Authors:Anirban Roy; Girish Kulkarni, P. Daniel Meerburg, Anthony Challinor, Carlo Baccigalupi, Andrea Lapi Martin G. Haehnelt First page: 003 Abstract: The search for primordial gravitational waves through the B -mode polarization pattern in the CMB is
one of the major goals of current and future CMB experiments. Besides foregrounds, a potential
hurdle in this search is the anisotropic secondary B -mode polarization generated by the scattering
of CMB photons off free electrons produced during patchy cosmological reionization. Robust
predictions of these secondary anisotropies are challenging because of uncertainties in the
reionization history. In this paper we revise estimates of the reionization-induced B -mode signal
by incorporating recent advances in the understanding of reionization through observations of the
Lyman-α forest. To derive these B -mode estimates, we use high-dynamic-range radiative transfer
simulations of reionization that are calibrated to the Lyα data. These simulations are also
consistent with a variety of other high-redshift observations. We find that... Citation: Journal of Cosmology and Astroparticle Physics PubDate: 2021-01-04T00:00:00Z DOI: 10.1088/1475-7516/2021/01/003 Issue No:Vol. 2021, No. 01 (2021)

Authors:T. Montandon; G. Patanchon B. van Tent First page: 004 Abstract: We perform a joint analysis of the power spectrum and the bispectrum of the CMB temperature and
polarization anisotropies to improve the constraints on isocurvature modes. We construct joint
likelihoods, both for the existing Planck data, and to make forecasts for the future LiteBIRD and
CMB-S4 experiments. We assume a general two-field inflation model with five free parameters, leading
to one isocurvature mode (which can be CDM density, neutrino density or neutrino velocity)
arbitrarily correlated with the adiabatic mode. We theoretically assess in which cases (of detecting
and/or fixing parameters) improvements can be expected, to guide our subsequent numerical analyses.
We find that for Planck, which detected neither isocurvature modes nor primordial non-Gaussianity,
the joint analysis does not improve the constraints in the general case. However, if we fix
additional parameters in the model, the improvements can be highly significant depending on the
chosen parameter values. ... Citation: Journal of Cosmology and Astroparticle Physics PubDate: 2021-01-04T00:00:00Z DOI: 10.1088/1475-7516/2021/01/004 Issue No:Vol. 2021, No. 01 (2021)

Authors:Eileen Giesel; Robert Reischke, Björn Malte Schäfer Dominic Chia First page: 005 Abstract: Statistical inference often involves models which are non-linear in the parameters and which
therefore typically exhibit non-Gaussian posterior distributions. These non-Gaussianities can be
prominent especially when data is limited or not constraining enough. Many computational and
analytical tools exist that can deal with non-Gaussian distributions, and empirical Gaussianisation
transforms can be constructed that can reduce the amount of non-Gaussianity in a distribution. In
this work, we employ methods from information geometry, which considers a set of probability
distributions for some given model to be a manifold with a metric Riemannian structure, given by the
Fisher information. In this framework we study the differential geometrical meaning of
non-Gaussianities in a higher order Fisher approximation, and their respective transformation
behaviour under re-parameterisation, which corresponds to a chart transition on the statistical
manifold. While weak non-Gaussianities van... Citation: Journal of Cosmology and Astroparticle Physics PubDate: 2021-01-04T00:00:00Z DOI: 10.1088/1475-7516/2021/01/005 Issue No:Vol. 2021, No. 01 (2021)

Authors:Guido D'Amico; Leonardo Senatore Pierre Zhang First page: 006 Abstract: We apply the Effective Field Theory of Large-Scale Structure to analyze the w CDM cosmological
model. By using the full shape of the power spectrum and the BAO post-reconstruction measurements
from BOSS, the Supernovae from Pantheon, and a prior from BBN, we set the competitive
CMB-independent limit w =−1.046 −0.052 +0.055 at 68% C.L. After adding the Planck CMB data, we find
w =−1.023 −0.030 +0.033 at 68% C.L. Our results are obtained using PyBird, a new, fast Python-based
code which we make publicly available. Citation: Journal of Cosmology and Astroparticle Physics PubDate: 2021-01-04T00:00:00Z DOI: 10.1088/1475-7516/2021/01/006 Issue No:Vol. 2021, No. 01 (2021)

Authors:H.C. Das; Ankit Kumar, Bharat Kumar, S.K. Biswal S.K. Patra First page: 007 Abstract: The effects of dark matter (DM) on the curvatures of the neutron star (NS) are examined by using the
stiff and soft relativistic mean-field equation of states. The curvatures of the NSs are calculated
with the variation of baryon density. It is found that the radial variation of different curvatures
significantly affected by DM inside the star. The surface curvature is found to be more remarkable
for the massive star. The effects of DM on the compactness of the maximum NS mass is less as
compared to canonical star. The binding energy of the NS goes towards positive with the increase of
DM momentum and makes the system unstable. Citation: Journal of Cosmology and Astroparticle Physics PubDate: 2021-01-05T00:00:00Z DOI: 10.1088/1475-7516/2021/01/007 Issue No:Vol. 2021, No. 01 (2021)

Authors:Ryotaro Kase; Shinji Tsujikawa First page: 008 Abstract: For a theory in which a scalar field ##IMG## [https://ej.iop.org/icons/Entities/phi.gif] {phi} has a
nonminimal derivative coupling to the Einstein tensor G μ ν of the form ##IMG##
[https://ej.iop.org/icons/Entities/phi.gif] {phi} G μ ν ∇ μ ∇ ν ##IMG##
[https://ej.iop.org/icons/Entities/phi.gif] {phi} , it is known that there exists a branch of static
and spherically-symmetric relativistic stars endowed with a scalar hair in their interiors. We study
the stability of such hairy solutions with a radial field dependence ##IMG##
[https://ej.iop.org/icons/Entities/phi.gif] {phi} ( r ) against odd- and even-parity perturbations.
We show tha... Citation: Journal of Cosmology and Astroparticle Physics PubDate: 2021-01-05T00:00:00Z DOI: 10.1088/1475-7516/2021/01/008 Issue No:Vol. 2021, No. 01 (2021)

Authors:G. Parimbelli; S. Anselmi, M. Viel, C. Carbone, F. Villaescusa-Navarro, P.S. Corasaniti, Y. Rasera, R. Sheth, G.D. Starkman I. Zehavi First page: 009 Abstract: The linear point (LP), defined as the mid-point between the dip and the peak of the two-point
clustering correlation function (TPCF), has been shown to be an excellent standard ruler for
cosmology. In fact, it is nearly redshift-independent, being weakly sensitive to non-linearities,
scale-dependent halo bias and redshift-space distortions. So far, these findings were tested
assuming that neutrinos are massless; in this paper we extend the analysis to massive-neutrino
cosmologies. In particular, we examine if the scale-dependent growth induced by neutrinos affects
the LP position and if it is possible to detect the neutrino masses using the shift of the LP
compared to the massless-neutrino case. For our purposes, we employ two sets of state-of-the-art N
-body simulations with massive neutrinos. For each of them we measure the TPCF of cold dark matter
(CDM) and halos and, to estimate the LP, fit the TPCF with a model-independent parametric fit in the
range of scales of the B... Citation: Journal of Cosmology and Astroparticle Physics PubDate: 2021-01-05T00:00:00Z DOI: 10.1088/1475-7516/2021/01/009 Issue No:Vol. 2021, No. 01 (2021)

Authors:Hua Zhai; Si-Yu Li, Mingzhe Li, Hong Li Xinmin Zhang. First page: 051 Abstract: The Chern-Simons term, through which the cosmic Axion-like field couples to the electromagnetic
field, has the effect to rotate CMB polarization directions and to break the CPT symmetry. This
rotation will change the CMB power spectra, no matter isotropic or anisotropic the rotation angle
is. In this paper we revisit this issue by further considering the correlations between the
anisotropic rotation angle α and the CMB temperature and CMB E polarization fields. These
correlations could be generated in the Axion-like models with nonzero potential under the adiabatic
initial condition. We first investigate how these correlations contribute further modifications to
the CMB power spectra, then calculate the CMB bispectra for the temperature and rotated polarization
fields. These bispectra would vanish if the T α and E α correlations are absent. So, they are useful
in searching for CPT violation and the T α and E α correlations arisen in the Axion-like m... Citation: Journal of Cosmology and Astroparticle Physics PubDate: 2020-12-31T00:00:00Z DOI: 10.1088/1475-7516/2020/12/051 Issue No:Vol. 2020, No. 12 (2020)