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Related papers: Optimal CMB estimators for bispectra from excited …

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The primordial four-point function encodes a wealth of information about the inflationary Universe. Despite extensive theoretical work, most models of four-point physics have never been compared to data. In this series, we conduct a…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-30 Oliver H. E. Philcox

Deep surveys of the CMB polarization have more information on the lensing signal than the quadratic estimators (QE) can capture. We showed in a recent work that a CMB lensing power spectrum built from a single optimized CMB lensing mass…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-15 Louis Legrand , Julien Carron

Solving excited states is a challenging task for interacting systems. For one-dimensional critical systems, however, excited states can be directly accessed from the eigenvectors of the local effective Hamiltonian that is constructed from…

Strongly Correlated Electrons · Physics 2026-05-28 Denise Cocchiarella , Mingru Yang , Yueshui Zhang , Mari Carmen Bañuls , Hong-Hao Tu , Yuhan Liu

A Quadratic Maximum Likelihood (QML) estimator is applied to the WMAP 5 year low resolution maps to compute the CMB angular power spectra at large scales for both temperature and polarization. Estimates and error bars for the six angular…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-02 A. Gruppuso , A. De Rosa , P. Cabella , F. Paci , F. Finelli , P. Natoli , G. de Gasperis , N. Mandolesi

We present a new linked cluster expansion for calculating properties of multiparticle excitation spectra to high orders. We use it to obtain the two-particle spectra for systems of coupled spin-half dimers. We find that even for weakly…

Strongly Correlated Electrons · Physics 2008-03-26 S. Trebst , H. Monien , C. J. Hamer , Z. Weihong , R. R. P. Singh

We present an excited-state-specific coupled-cluster approach in which both the molecular orbitals and cluster amplitudes are optimized for an individual excited state. The theory is formulated via a pseudoprojection of the traditional…

Chemical Physics · Physics 2023-11-27 Harrison Tuckman , Eric Neuscamman

In this paper we compute the CMB bispectrum for bouncing models motivated by Loop Quantum Cosmology. Despite the fact that the primordial bispectrum of these models is decaying exponentially above a large pivot scale, we find that the…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-12 Paola C. M. Delgado , Ruth Durrer , Nelson Pinto-Neto

We study the angular bispectrum of local type arising from the (possibly correlated) combination of a primordial adiabatic mode with an isocurvature one. Generically, this bispectrum can be decomposed into six elementary bispectra. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 David Langlois , Bartjan van Tent

Understanding the properties of excited states of complex molecules is crucial for many chemical and physical processes. Calculating these properties is often significantly more resource-intensive than calculating their ground state…

Quantum Physics · Physics 2025-05-08 Manuel Hagelüken , Marco F. Huber , Marco Roth

A general expression is obtained for the matrix element of an m-body operator between coherent states constructed from multiple orthogonal coherent boson species. This allows the coherent state formalism to be applied to states possessing…

Mathematical Physics · Physics 2008-11-26 M. A. Caprio

We describe the details of the binned bispectrum estimator as used for the official 2013 and 2015 analyses of the temperature and polarization CMB maps from the ESA Planck satellite. The defining aspect of this estimator is the…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-02 Martin Bucher , Benjamin Racine , Bartjan van Tent

The direct evaluation of manifestly optimal, cut-sky CMB power spectrum and bispectrum estimators is numerically very costly, due to the presence of inverse-covariance filtering operations. This justifies the investigation of alternative…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-01 H. F. Gruetjen , J. R. Fergusson , M. Liguori , E. P. S. Shellard

To unlock the vast potential of the CMB trispectrum, we require both robust estimators and efficient computational tools. In this work, we introduce the public code PolySpec: a suite of quartic estimators designed to measure the amplitudes…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-30 Oliver H. E. Philcox

We build an inflationary model based on Degenerate Higher Order Scalar Tensor (DHOST) theories in a de Sitter background. We determine the scale-dependent power spectrum of curvature perturbations in these theories and we show that such a…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-25 Andrei Lazanu

The calculation of molecular excited states is critically important to decipher a plethora of molecular properties. In this manuscript, we develop an equation of motion formalism on top of a bi-exponentially parametrized ground state…

Chemical Physics · Physics 2024-01-09 Anish Chakraborty , Pradipta Kumar Samanta , Rahul Maitra

Recently developed neural network-based wave function methods are capable of achieving state-of-the-art results for finding the ground state in real space. In this work, a neural network-based method is used to compute excited states. We…

Computational Physics · Physics 2021-10-04 Yimeng Min

The CMB bispectrum generated by second-order effects at recombination can be calculated analytically when one of the three modes has a wavelength much longer than the other two and is outside the horizon at recombination. This was pointed…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Paolo Creminelli , Cyril Pitrou , Filippo Vernizzi

We reexamine $\Delta$CCSD, a state-specific coupled-cluster (CC) with single and double excitations (CCSD) approach that targets excited states through the utilization of non-Aufbau determinants. This methodology is particularly efficient…

Chemical Physics · Physics 2024-06-13 Yann Damour , Anthony Scemama , Denis Jacquemin , Fábris Kossoski , Pierre-François Loos

Eigenvector continuation (EC) has recently attracted a lot attention in nuclear structure and reactions as a variational resummation tool for many-body expansions. While previous applications focused on ground-state energies, excited states…

Nuclear Theory · Physics 2022-06-09 Margarida Companys Franzke , Alexander Tichai , Kai Hebeler , Achim Schwenk

We extend our hybrid linear-method/accelerated-descent variational Monte Carlo optimization approach to excited states and investigate its efficacy in double excitations. In addition to showing a superior statistical efficiency when…

Chemical Physics · Physics 2022-02-24 Leon Otis , Isaac M. Craig , Eric Neuscamman