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We propose efficient algorithms for classically simulating Gaussian unitaries and measurements applied to non-Gaussian initial states. The constructions are based on decomposing the non-Gaussian states into linear combinations of Gaussian…

Quantum Physics · Physics 2026-02-26 Oliver Hahn , Ryuji Takagi , Giulia Ferrini , Hayata Yamasaki

We present a general formalism that provides a systematic computation of the linear and non-linear perturbations for an arbitrary number of cosmological fluids in the early Universe going through various transitions, in particular the decay…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 David Langlois , Angela Lepidi

The set-up of the initial conditions in cosmological N-body simulations is usually implemented by rescaling the desired low-redshift linear power spectrum to the required starting redshift consistently with the Newtonian evolution of the…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-18 Matteo Zennaro , Julien Bel , Francisco Villaescusa-Navarro , Carmelita Carbone , Emiliano Sefusatti , Luigi Guzzo

Initial conditions for (Newtonian) cosmological N-body simulations are usually set by re-scaling the present-day power spectrum obtained from linear (relativistic) Boltzmann codes to the desired initial redshift of the simulation. This…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-28 Christian Fidler , Thomas Tram , Cornelius Rampf , Robert Crittenden , Kazuya Koyama , David Wands

Focusing on the local type primordial non-Gaussianities, we study the bispectrum and trispectrum during a non-minimal slow-roll inflation. We use the so-called $\delta N$ formalism to investigate the super-horizon evolution of the…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-28 Kosar Asadi , Kourosh Nozari

Quantum molecular dynamics requires an accurate representation of the molecular potential energy surface from a minimal number of electronic structure calculations, particularly for nonadiabatic dynamics where excited states are required.…

Chemical Physics · Physics 2016-08-24 Charles W. Heaps , David A. Mazziotti

We compute analytic expressions for the non-linearity parameters characterizing the bi- and tri-spectrum of primordial curvature perturbations generated during an inflationary epoch of the early universe driven by an arbitrary number of…

High Energy Physics - Theory · Physics 2011-11-04 Diana Battefeld , Thorsten Battefeld

Initial conditions for cosmological N-body simulations are usually calculated by rescaling the present day linear power spectrum obtained from an Einstein-Boltzmann solver to the initial time employing the scale-independent matter growth…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-12 Christian Fidler , Alexander Kleinjohann

The late-time effect of primordial non-Gaussianity offers a window into the physics of inflation and the very early Universe. In this work we study the consequences of a particular class of primordial non-Gaussianity that is fully…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-09 G. A. Peña , G. N. Candlish

We investigate the possibility of generating initial conditions for cosmological N-body simulations by simulating a system whose correlations at thermal equilibrium approximate well those of cosmological density perturbations. The system is…

Astrophysics · Physics 2009-11-10 M. Joyce , D. Levesque , B. Marcos

We address the generation of initial conditions (ICs) for GRAMSES, a code for nonlinear general relativistic (GR) $N$-body cosmological simulations recently introduced in Ref. [1]. GRAMSES adopts a constant mean curvature slicing with a…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-06 Cristian Barrera-Hinojosa , Baojiu Li

The description of the abundance and clustering of halos for non-Gaussian initial conditions has recently received renewed interest, motivated by the forthcoming large galaxy and cluster surveys, which can potentially yield constraints of…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-02 M. Grossi , L. Verde , C. Carbone , K. Dolag , E. Branchini , F. Iannuzzi , S. Matarrese , L. Moscardini

Providing initial conditions is an essential procedure for numerical simulations of galaxies. The initial conditions for idealised individual galaxies in $N$-body simulations should resemble observed galaxies and be dynamically stable for…

Instrumentation and Methods for Astrophysics · Physics 2020-03-25 Yohei Miki , Masayuki Umemura

We develop a new formalism for the component separation method Spectral Matching Independent Component Analysis (SMICA) in order to include the information contained in the foregrounds beyond second-order statistics. We also develop a…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-19 M. Citran , H. V. Tran , G. Patanchon , B. van Tent

We introduce a general class of models for charaterizing the non-Gaussian properties of foreground contaminants in the cosmic microwave background with view towards the removal of the non-primordial non-Gaussian signal from the primordial…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-05 C. S. Carvalho

Quantum non-Gaussian states represent an important class of highly non-classical states whose preparation requires quantum operations or measurements beyond the class of Gaussian operations and statistical mixing. Here we derive criteria…

Quantum Physics · Physics 2021-07-21 Jaromír Fiurášek , Lukáš Lachman , Radim Filip

To efficiently probe primordial non-Gaussianity using Cosmic Microwave Background (CMB) data, we require theoretical predictions that are factorizable, \textit{i.e.}\ those whose kinematic dependence can be separated. This property does not…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-25 Oliver H. E. Philcox , Kunhao Zhong , Salvatore Samuele Sirletti

Primordial non-Gaussianity generated in an inflationary model where inflation is preceded by a radiation era is discussed. It is shown that both bispectrum and trispectrum non-Gaussianities are enhanced due to the presence of…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-04 Suratna Das

We present a method to implement relativistic corrections to the evolution of dark matter structures in Newtonian simulations of a LCDM universe via the initial conditions. We take the nonlinear correspondence between the Lagrangian…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-30 Miguel Enríquez , Juan Carlos Hidalgo , Octavio Valenzuela

Reconstructing cosmological initial conditions (ICs) from late-time observations is a difficult task, which relies on the use of computationally expensive simulators alongside sophisticated statistical methods to navigate multi-million…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-22 Oleg Savchenko , Florian List , Guillermo Franco Abellán , Noemi Anau Montel , Christoph Weniger