相关论文: Testing charge quantization with axion string-indu…
The cosmic microwave background (CMB) fluctuations effectively measure the basic properties of the universe during the recombination epoch. CMB measurements fix the distance to the surface of last scatter, the sound horizon of the…
We describe exact cosmological solutions with rotation and expansion in the low-energy effective string theory. These models are spatially homogeneous (closed Bianchi type IX) and they belong to the family of shear-free metrics which are…
We provide an analytical approach to the second-order Cosmic Microwave Background (CMB) anisotropies generated by the non-linear dynamics taking place at last scattering. We study the acoustic oscillations of the photon-baryon fluid in the…
Simulation-based inference (SBI) is a powerful inference technique for cases where the exact functional form of the likelihood is not known. A prime example is the likelihood of cross-correlation power spectra of the cosmic microwave…
The recent data from the Boomerang and MAXIMA-1 balloon flights have marked the beginning of the precision era of Cosmic Microwave Background anisotropy (CMB) measurements. We investigate the observational constraints from the current CMB…
As a test of the standard inflationary cosmology, which generically predicts nearly scale-invariant spectrum of primordial curvature fluctuations, we perform Markov-Chain Monte-Carlo analysis to search for possible modulations in the power…
We calculate the bispectrum of the Cosmic Microwave Background (CMB) temperature anisotropies induced by the second-order fluctuations in the Boltzmann equation. In this paper, which is one of a series of papers on the numerical calculation…
An algorithm is proposed for denoising the signal induced by cosmic strings in the cosmic microwave background (CMB). A Bayesian approach is taken, based on modeling the string signal in the wavelet domain with generalized Gaussian…
We present a new, model-independent approach for measuring non-Gaussianity of the Cosmic Microwave Background (CMB) anisotropy pattern. Our approach is based on the empirical distribution function of the normalized spherical harmonic…
The latest Planck results show a power deficit in the temperature anisotropies near $\ell \approx 20$ in the cosmic microwave background (CMB). This observation can hardly be explained within the standard inflationary…
We examine the two-point correlation function of local maxima in temperature fluctuations at the last scattering surface when this stochastic field is modified by the additional fluctuations produced by straight cosmic strings via the…
Chern-Simons gravity coupled to the scalar sector through a generic coupling function $f(\phi)$ can be tested at the very high energies of the inflationary period. In 1706.04627, we computed the theoretical parity breaking signatures of the…
This paper is concerned with small angular scale experiments for the observation of cosmic microwave background anisotropies. In the absence of beam, the effects of partial coverage and pixelisation are disentangled and analyzed (using…
Cosmological birefringence is a rotation of the polarization plane of photons coming from sources of astrophysical and cosmological origin. The rotation can also depend on the energy of the photons and not only on the distance of the source…
In this thesis we investigate quantum aspects of the Green-Schwarz superstring in various AdS backgrounds relevant for the AdS/CFT correspondence, providing several examples of perturbative computations in the corresponding integrable…
The polarized light of the cosmic microwave background is sensitive to new physics that violates parity symmetry. For example, the interaction of photons with the fields of elusive dark matter and dark energy could cause a uniform rotation…
We investigate the possibility of reconstructing the initial spectrum of density fluctuations from the cosmic microwave background (CMB) anisotropy. As a first step toward this program, we consider a spatially flat, CDM dominated universe.…
Reionization of the cosmic neutral hydrogen by the first stars in the Universe is an inhomogeneous process which produces spatial fluctuations in free electron density. These fluctuations lead to observable signatures in cosmological probes…
Axion strings are horizon-size topological defects that may be produced in the early Universe. Ultra-light axion-like particles may form strings that persist to temperatures below that of big bang nucleosynthesis. Such strings have been…
One of the major goals of future cosmic microwave background (CMB) $B$-mode polarization experiments is the detection of primordial gravitational waves through an unbiased measurement of the tensor-to-scalar ratio $r$. Robust detection of…