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Markov Chain Monte Carlo (MCMC) sampler is widely used for cosmological parameter estimation from CMB and other data. However, due to the intrinsic serial nature of the MCMC sampler, convergence is often very slow. Here we present a fast…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-12 Santanu Das , Tarun Souradeep

We calculate the spectral functions of model systems describing 5f-compounds adopting Cluster Perturbation Theory. The method allows for an accurate treatment of the short-range correlations. The calculated excitation spectra exhibit…

Strongly Correlated Electrons · Physics 2007-05-23 F. Pollmann , G. Zwicknagl

The interpretation of cosmological observables requires the use of increasingly sophisticated theoretical models. Since these models are becoming computationally very expensive and display non-trivial uncertainties, the use of standard…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-14 Marcos Pellejero-Ibañez , Raul E. Angulo , Giovanni Aricó , Matteo Zennaro , Sergio Contreras , Jens Stücker

Loop corrections to the power spectrum are frequently computed using approximate non-linear kernels adopted from an Einstein de-Sitter (EdS) cosmology. We present an algorithm that allows us to take the full time- and scale-dependence of…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-04 Mathias Garny , Petter Taule

The power spectrum is the most commonly applied summary statistics to extract cosmological information from the observed three-dimensional distribution of galaxies in spectroscopic surveys. We present CLASS-OneLoop, a new numerical tool,…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-28 Dennis Linde , Azadeh Moradinezhad Dizgah , Christian Radermacher , Santiago Casas , Julien Lesgourgues

We develop a fast technique based on the generalized slow roll (GSR) approach for computing the curvature bispectrum of inflationary models with features. We show that all triangle configurations can be expressed in terms of three simple…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-02 Peter Adshead , Wayne Hu , Cora Dvorkin , Hiranya V. Peiris

Upcoming Large Scale Structure surveys aim to achieve an unprecedented level of precision in measuring galaxy clustering. However, accurately modeling these statistics may require theoretical templates that go beyond second-order…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-21 M. Icaza-Lizaola , Yong-Seon Song , Minji Oh , Yi Zheng

Cluster perturbation theory is a technique for calculating the spectral weight of Hubbard models of strongly correlated electrons, which combines exact diagonalizations on small clusters with strong-coupling perturbation theory at leading…

Strongly Correlated Electrons · Physics 2009-11-07 D. Sénéchal , D. Pérez , D. Plouffe

We present a fast Markov Chain Monte-Carlo exploration of cosmological parameter space. We perform a joint analysis of results from recent CMB experiments and provide parameter constraints, including sigma_8, from the CMB independent of…

Astrophysics · Physics 2008-11-26 Antony Lewis , Sarah Bridle

This is part two in a series of papers in which we investigate an approach based on Lagrangian perturbation theory (LPT) to study the non-linear evolution of the large-scale structure distribution in the universe. Firstly, we compute the…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-15 Cornelius Rampf , Yvonne Y. Y. Wong

We derive and prove the `fast response' formula for the linear response, the parameter derivatives of long-time-averaged statistics, of hyperbolic deterministic chaotic systems. The expression is pointwisely defined so we can compute the…

Dynamical Systems · Mathematics 2025-12-15 Angxiu Ni

We have developed a fast, accurate and generally applicable method for inferring the power spectrum and its uncertainties from maps of the cosmic microwave background (CMB) in the presence of inhomogeneous and correlated noise. For maps…

Astrophysics · Physics 2014-10-13 O. Doré , L. Knox , A. Peel

We predict neutron-proton scattering cross-sections and polarization observables up to next-to-next-to-next-to leading order in a renormalization-group invariant description of the strong nucleon-nucleon interaction. Low-energy constants…

Nuclear Theory · Physics 2024-06-12 Oliver Thim , Andreas Ekström , Christian Forssén

The confrontation of the Cosmic Microwave Background (CMB) theoretical angular power spectrum with available data often requires the calculation of large numbers of power spectra. The standard practice is to use a fast code to compute the…

Astrophysics · Physics 2009-10-31 Kris Sigurdson , Douglas Scott

Inflation gives rise to a nearly scale-invariant spectrum of tensor perturbations (gravitational waves), their contribution to the Cosmic Background Radiation (CBR) anisotropy depends upon the present cosmological parameters as well as…

Astrophysics · Physics 2014-10-13 Michael S. Turner , Yun Wang

We present the first calculation of the bispectrum of the matter perturbations induced by cosmic strings. The calculation is performed in two different ways: the first uses the unequal time correlators (UETCs) of the string network -…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Donough Regan , Mark Hindmarsh

The marked power spectrum is capable of placing far tighter constraints on cosmological parameters (particularly the neutrino mass) than the conventional power spectrum. What new information does it contain beyond conventional statistics?…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-19 Oliver H. E. Philcox , Elena Massara , David N. Spergel

We develop a non-perturbative functional framework for computing real-time correlation functions in strongly correlated systems. The framework is based on the spectral representation of correlation functions and dimensional regularisation.…

High Energy Physics - Theory · Physics 2021-01-04 Jan Horak , Jan M. Pawlowski , Nicolas Wink

In conventional model independent approaches, the power spectrum of primordial perturbations is characterized by such free parameters as spectral index, its running, the running of running, and the tensor-to-scalar ratio. In this work we,…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-15 Moslem Zarei

Motivated by applications in thermal QCD and cosmology, we elaborate on a general method for computing next-to-leading order spectral functions for composite operators at vanishing spatial momentum, accounting for real, virtual as well as…

High Energy Physics - Phenomenology · Physics 2015-05-30 M. Laine , A. Vuorinen , Y. Zhu