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In the recent work of S. Sharma \emph{et al.}, (arxiv.org: arxiv:0912.1118), a single-electron spectrum associated with the natural orbitals was defined as the derivative of the total energy with respect to the occupation numbers at half…

Chemical Physics · Physics 2012-03-07 E. N. Zarkadoula , S. Sharma , J. K. Dewhurst , E. K. U. Gross , N. N. Lathiotakis

A conceptual difficulty in formulating the density functional theory of the fractional quantum Hall effect is that while in the standard approach the Kohn-Sham orbitals are either fully occupied or unoccupied, the physics of the fractional…

Strongly Correlated Electrons · Physics 2017-05-12 Jianyun Zhao , Manisha Thakurathi , Manish Jain , Diptiman Sen , J. K. Jain

We consider the application of Koopman theory to nonlinear partial differential equations. We demonstrate that the observables chosen for constructing the Koopman operator are critical for enabling an accurate approximation to the nonlinear…

Pattern Formation and Solitons · Physics 2016-07-26 J. Nathan Kutz , Joshua L. Proctor , Steven L. Brunton

Density Functional Theory (DFT) is a pivotal method within quantum chemistry and materials science, with its core involving the construction and solution of the Kohn-Sham Hamiltonian. Despite its importance, the application of DFT is…

We introduce a novel energy functional for ground-state electronic-structure calculations. Its fundamental variables are the natural spin-orbitals of the implied singlet many-body wave function and their joint occupation probabilities. The…

Chemical Physics · Physics 2015-06-23 Ralph Gebauer , Morrel H. Cohen , Roberto Car

Koopman and Perron-Frobenius operators for dynamical systems have been getting popular in a number of fields in science these days. Properties of the Koopman operator essentially depend on the choice of function spaces where it acts.…

Dynamical Systems · Mathematics 2024-01-29 Masahiro Ikeda , Isao Ishikawa , Corbinian Schlosser

We present an accurate and efficient finite-difference formulation and parallel implementation of Kohn-Sham Density (Operator) Functional Theory (DFT) for non periodic systems embedded in a bulk environment. Specifically, employing…

Computational Physics · Physics 2020-11-30 Swarnava Ghosh , Kaushik Bhattacharya

Nonlocal kinetic energy density functionals (KEDFs) with density-dependent kernels are currently the most accurate functionals available for orbital-free density functional theory (OF-DFT) calculations. However, despite advances in…

Materials Science · Physics 2024-12-05 Yongshuo Chen , Cheng Ma , Boning Cui , Tian Cui , Wenhui Mi , Qiang Xu , Yanchao Wang , Yanming Ma

Kohn-Sham density functional theory (DFT) has long struggled with the accurate description of strongly correlated and open shell systems and improvements have been minor even in the newest hybrid functionals. In this Letter we treat the…

Chemical Physics · Physics 2021-04-01 Danny Gibney , Jan-Niklas Boyn , David A. Mazziotti

We propose a fully data-driven, Koopman-based framework for statistically robust control of discrete-time nonlinear systems with linear embeddings. Establishing a connection between the Koopman operator and contraction theory, it offers…

Robotics · Computer Science 2026-03-24 Koki Hirano , Hiroyasu Tsukamoto

The paper is about the computation of the principal spectrum of the Koopman operator (i.e., eigenvalues and eigenfunctions). The principal eigenfunctions of the Koopman operator are the ones with the corresponding eigenvalues equal to the…

Dynamical Systems · Mathematics 2023-07-14 Shankar A. Deka , Sriram S. K. S. Narayanan , Umesh Vaidya

We present a computational scheme for orbital-free density functional theory (OFDFT) that simultaneously provides access to all-electron values and preserves the OFDFT linear scaling as a function of the system size. Using the projector…

Computational Physics · Physics 2014-12-23 J. Lehtomäki , I. Makkonen , M. A. Caro , A. Harju , O. Lopez-Acevedo

The existing research on spectral algorithms, applied within a Reproducing Kernel Hilbert Space (RKHS), has primarily focused on general kernel functions, often neglecting the inherent structure of the input feature space. Our paper…

Machine Learning · Statistics 2024-03-08 Weichun Xia , Lei Shi

Research on Koopman operator theory has focused on three key areas for several decades: the mathematical structure of the Koopman eigenfunction space, the basis of this space, and the ability to represent nonlinear dynamics as linear. This…

Dynamical Systems · Mathematics 2023-06-13 Ido Cohen , Eli Appleboim

We propose a novel scheme to bring reduced density matrix functional theory (RDMFT) into the realm of density functional theory (DFT) that preserves the accurate density functional description at equilibrium, while incorporating accurately…

Chemical Physics · Physics 2014-11-07 Nektarios N. Lathiotakis , Nicole Helbig , Angel Rubio , Nikitas I. Gidopoulos

Mean field control provides a robust framework for coordinating large-scale populations with complex interactions and has wide applications across diverse fields. However, the inherent nonlinearity and the presence of unknown system…

Optimization and Control · Mathematics 2024-11-12 Yuhan Zhao , Juntao Chen , Yingdong Lu , Quanyan Zhu

Density functional theory (DFT) embedding provides a formally exact framework for interfacing correlated wave-function theory (WFT) methods with lower-level descriptions of electronic structure. Here, we report techniques to improve the…

Chemical Physics · Physics 2015-06-12 Jason D. Goodpaster , Taylor A. Barnes , Frederick R. Manby , Thomas F. Miller

The Wang-Teter-like nonlocal kinetic energy density functional (KEDF) in the framework of orbital-free density functional theory, while successful in some bulk systems, exhibits a critical Blanc-Cances instability [J. Chem. Phys. 122,…

Materials Science · Physics 2026-03-17 Liang Sun , Mohan Chen

Spatial temporal reconstruction of dynamical system is indeed a crucial problem with diverse applications ranging from climate modeling to numerous chaotic and physical processes. These reconstructions are based on the harmonious…

Dynamical Systems · Mathematics 2025-05-13 Nishant Panda , Himanshu Singh , J. Nathan Kutz

Many-body functionals of the Green's function can provide fundamental advances in electronic-structure calculations, due to their ability to accurately predict both spectral and thermodynamic properties, such as angle-resolved photoemission…

Strongly Correlated Electrons · Physics 2025-08-26 Tommaso Chiarotti , Matteo Quinzi , Andrea Pintus , Mario Caserta , Andrea Ferretti , Nicola Marzari