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Related papers: GridSPT: Grid-based calculation for perturbation t…

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We describe a low cost alternative to the standard variational DMRG (density matrix renormalization group) algorithm that is analogous to the combination of selected configuration interaction plus perturbation theory (SCI+PT). We denote the…

Chemical Physics · Physics 2018-03-28 Sheng Guo , Zhendong Li , Garnet Kin-Lic Chan

Purpose: The computation methods for modeling, controlling and optimizing the transforming grid are evolving rapidly. We review and systemize knowledge for a special class of computation methods that solve large-scale power grid…

Systems and Control · Electrical Eng. & Systems 2025-01-09 Amritanshu Pandey , Mads Almassalkhi , Sam Chevalier

Data clustering with uneven distribution in high level noise is challenging. Currently, HDBSCAN is considered as the SOTA algorithm for this problem. In this paper, we propose a novel clustering algorithm based on what we call graph of…

Machine Learning · Computer Science 2020-09-25 Zhangyang Gao , Haitao Lin , Stan. Z Li

I discuss new results concerning the evolution of the bispectrum due to gravitational instability from gaussian initial conditions using one-loop perturbation theory (PT). Particular attention is paid to the transition from weakly…

Astrophysics · Physics 2007-05-23 Roman Scoccimarro

Due to the extensive availability of operation data, data-driven methods show strong capabilities in predicting building energy loads. Buildings with similar features often share energy patterns, reflected by spatial dependencies in their…

Machine Learning · Computer Science 2025-07-29 Yongzheng Liu , Yiming Wang , Po Xu , Yingjie Xu , Yuntian Chen , Dongxiao Zhang

In our previous paper, we have proposed a new algorithm to calculate the power spectrum of the curvature perturbations generated in inflationary universe with use of the stochastic approach. Since this algorithm does not need the…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-15 Tomohiro Fujita , Masahiro Kawasaki , Yuichiro Tada

We develop the BRST approach for all massless integer and half-integer higher spins in 4D Minkowski space, using the two component spinor nota- tion and develop the Lagrangian formulation for supersymmetric higher spin models. It is shown…

High Energy Physics - Theory · Physics 2016-01-27 I. L. Buchbinder , K. Koutrolikos

The integrated perturbation theory (iPT) is a set of methods in nonlinear perturbation theory for the structure formation in the Universe. In Papers I and II [arXiv:2210.10435, arXiv:2210.11085], the basic formalism and technical methods of…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-23 Takahiko Matsubara

A partial-active-space (PAS) multi-state (MS) multi-reference second-order perturbation theory (MRPT2) for the electronic structure of strongly correlated systems of electrons, dubbed PASPT2, is formulated by linearizing the intermediate…

Chemical Physics · Physics 2026-05-21 Chunzhang Liu , Ning Zhang , Wenjian Liu

We calculate the lowest-order non-linear contributions to the power spectrum, two-point correlation function, and smoothed variance of the density field, for Gaussian initial conditions and scale-free initial power spectra, $P(k) \sim k^n$.…

Astrophysics · Physics 2009-10-28 Roman Scoccimarro , Josh Frieman

Quantum state tomography (QST) is a widely employed technique for characterizing the state of a quantum system. However, it is plagued by two fundamental challenges: computational and experimental complexity grows exponentially with the…

Quantum Physics · Physics 2025-11-12 Akshay Gaikwad , Manuel Sebastian Torres , Shahnawaz Ahmed , Anton Frisk Kockum

Perturbation Theory (PT) applied to a cosmological density field with Gaussian initial fluctuations suggests a specific hierarchy for the correlation functions when the variance is small. In particular quantitative predictions have been…

Astrophysics · Physics 2009-10-30 D. Munshi , F. Bernardeau , A. L. Melott , R. Schaeffer

This text describes a method to simultaneously reconstruct flow states and determine particle properties from Lagrangian particle tracking (LPT) data. LPT is a popular measurement strategy for fluids in which particles in a flow are…

Fluid Dynamics · Physics 2023-11-16 Ke Zhou , Samuel J. Grauer

Density matrix perturbation theory [Phys. Rev. Lett. Vol. 92, 193001 (2004)] provides an efficient framework for the linear scaling computation of response properties [Phys. Rev. Lett. Vol. 92, 193002 (2004)]. In this article, we generalize…

Computational Physics · Physics 2009-11-11 Anders M. N. Niklasson , Valery Weber , Matt Challacombe

Nowadays, various stakeholders involved in the analysis of electric power distribution grids face difficulties in the data acquisition related to the grid topology and parameters of grid assets. To mitigate the problem and possibly…

Systems and Control · Electrical Eng. & Systems 2024-08-27 Chandra Sekhar Charan Dande , Luca Mattorolo , Joel da Silva Andre , Lydia Lavecchia , Nikolaos Efkarpidis , Damiano Toffanin

In this work, we present a high-fidelity and efficient point-particle direct numerical simulation framework based on a multi-block overset curvilinear grid system, enabling large-scale Lagrangian particle tracking in complex geometries with…

Fluid Dynamics · Physics 2025-09-10 Taiyang Wang , Baoqing Meng , Baolin Tian , Yaomin Zhao

Accurately predicting the dynamic responses of building structures under seismic loads is essential for ensuring structural safety and minimizing potential damage. This critical aspect of structural analysis allows engineers to evaluate how…

Computational Engineering, Finance, and Science · Computer Science 2024-10-29 Shiqiao Meng , Ying Zhou , Qinghua Zheng , Bingxu Liao , Mushi Chang , Tianshu Zhang , Abderrahim Djerrad

The field-theoretical approach is reviewed. Perturbations in general relativity as well as in an arbitrary $D$-dimensional metric theory are studied on a background, which is a solution (arbitrary) of the theory. Lagrangian for…

General Relativity and Quantum Cosmology · Physics 2008-10-16 A. N. Petrov

Numerical Stochastic Perturbation Theory (NSPT) has over the years proved to be a valuable tool, in particular being able to reach unprecedented orders for Lattice Gauge Theories, whose perturbative expansions are notoriously cumbersome.…

High Energy Physics - Lattice · Physics 2022-12-22 Paolo Baglioni , Francesco Di Renzo

We study the nonlinear propagator, a key ingredient in renormalized perturbation theory (RPT) that allows a well-controlled extension of perturbation theory into the nonlinear regime. We show that it can be thought as measuring the memory…

Astrophysics · Physics 2009-11-13 M. Crocce , R. Scoccimarro
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