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Using principles of asymptotic analysis, we derive the exact leading corrections to the Thomas-Fermi kinetic energy approximation for Kohn-Sham electrons for slabs. This asymptotic expansion approximation includes crucial quantum…

Materials Science · Physics 2024-02-21 Pavel Okun , Antonio C. Cancio , Kieron Burke

This is a tutorial introduction to the functional analysis mathematics needed in many physical problems, such as in waves in continuous media. Functional analysis takes us beyond finite matrices, allowing us to work with infinite sets of…

Functional Analysis · Mathematics 2019-04-15 David A. B. Miller

Localized basis sets in the projector augmented wave formalism allow for computationally efficient calculations within density functional theory (DFT). However, achieving high numerical accuracy requires an extensive basis set, which also…

Materials Science · Physics 2020-11-18 G. Gandus , A. Valli , D. Passerone , R. Stadler

Within the nuclear-electronic orbital (NEO) framework, the real-time NEO time-dependent density functional theory (RT-NEO-TDDFT) approach enables the simulation of coupled electronic-nuclear dynamics. In this approach, the electrons and…

Chemical Physics · Physics 2023-03-22 Tao E. Li , Sharon Hammes-Schiffer

The natural orbitals and natural occupation numbers of various N = Z, sp and sd shell nuclei are calculated by applying a correlated one-body density matrix. The correlated density matrix has been evaluated by considering central…

Nuclear Theory · Physics 2013-08-21 V. P. Psonis , Ch. C. Moustakidis , S. E. Massen

Orbital-free density functional theory (OFDFT) is a quantum chemistry formulation that has a lower cost scaling than the prevailing Kohn-Sham DFT, which is increasingly desired for contemporary molecular research. However, its accuracy is…

Machine Learning · Statistics 2024-03-12 He Zhang , Siyuan Liu , Jiacheng You , Chang Liu , Shuxin Zheng , Ziheng Lu , Tong Wang , Nanning Zheng , Bin Shao

For a quantum system of N identical, harmonically interacting particles in a one-dimensional harmonic trap we calculate for the bosonic and fermionic ground state the corresponding 1-particle reduced density operator $\rho_1$ analytically.…

Quantum Physics · Physics 2015-06-16 Christian Schilling

This textbook introduces the basic concepts of the theory of causal fermion systems, a recent approach to the description of fundamental physics. The theory yields quantum mechanics, general relativity and quantum field theory as limiting…

Mathematical Physics · Physics 2025-10-24 Felix Finster , Sebastian Kindermann , Jan-Hendrik Treude

The nuclear-electronic orbital (NEO) method is a well-established approach for treating nuclei quantum mechanically in molecular systems beyond the usual Born-Oppenheimer approximation. In this work, we present a strategy to implement the…

Computational Physics · Physics 2022-06-29 Jianhang Xu , Ruiyi Zhou , Zhen Tao , Christopher Malbon , Volker Blum , Sharon Hammes-Schiffer , Yosuke Kanai

Bohmian mechanics provides an explanation of quantum phenomena in terms of point particles guided by wave functions. This review focuses on the formalism of non-relativistic Bohmian mechanics, rather than its interpretation. Although the…

Quantum Physics · Physics 2014-10-21 A. Benseny , G. Albareda , A. S. Sanz , J. Mompart , X. Oriols

The route to reliable quantum nanoelectronic devices hinges on precise control of the electrostatic environment. For this reason, accurate methods for electrostatic simulations are essential in the design process. The most widespread…

Mesoscale and Nanoscale Physics · Physics 2023-02-28 Waldemar Svejstrup , Andrea Maiani , Kevin Van Hoogdalem , Karsten Flensberg

The correct description of nondynamic correlation by electronic structure methods not belonging to the multireference family is a challenging issue. The transition of $D_{2h}$ to $D_{4h}$ symmetry in H$_4$ molecule is among the most simple…

Chemical Physics · Physics 2017-11-16 Eloy Ramos-Cordoba , Xabier Lopez , Mario Piris , Eduard Matito

Spectral decomposition of linear operators plays a central role in many areas of machine learning and scientific computing. Recent work has explored training neural networks to approximate eigenfunctions of such operators, enabling scalable…

Machine Learning · Computer Science 2025-10-28 J. Jon Ryu , Samuel Zhou , Gregory W. Wornell

For translationally invariant one-band lattice models, we exploit the ab initio knowledge of the natural orbitals to simplify reduced density matrix functional theory (RDMFT). Striking underlying features are discovered: First, within each…

Quantum Physics · Physics 2019-01-08 Christian Schilling , Rolf Schilling

The interest into parton distribution functions (PDFs) and fragmentation functions (FFs) in current high energy physics research is twofold. On the one hand, they are fundamental objects to conduct precision phenomenology studies, e.g. at…

High Energy Physics - Phenomenology · Physics 2025-09-22 Tanishq Sharma

We propose a novel extension to symmetrized neural network operators by incorporating fractional and mixed activation functions. This study addresses the limitations of existing models in approximating higher-order smooth functions,…

Machine Learning · Statistics 2025-01-22 Rômulo Damasclin Chaves dos Santos , Jorge Henrique de Oliveira Sales

In approximate Kohn-Sham density-functional theory, self-interaction manifests itself as the dependence of the energy of an orbital on its fractional occupation. This unphysical behavior translates into qualitative and quantitative errors…

Materials Science · Physics 2010-09-28 Ismaila Dabo , Andrea Ferretti , Nicolas Poilvert , Yanli Li , Nicola Marzari , Matteo Cococcioni

Any rigorous approach to first-order reduced density (1RDM) matrix functional theory faces the phase dilemma, that is, having to deal with a large number of possible combinations of signs in terms of the electron-electron interaction…

Chemical Physics · Physics 2018-04-18 Ion Mitxelena , Mauricio Rodríguez-Mayorga , Mario Piris

We introduce a practical hybrid approach that combines orbital-free density functional theory (DFT) with Kohn-Sham DFT for speeding up first-principles molecular dynamics simulations. Equilibrated ionic configurations are generated using…

The fractional quantum Hall effect remains a captivating area in condensed matter physics, characterized by strongly correlated topological order, which manifests as fractionalized excitations and anyonic statistics. Numerical simulations,…

Strongly Correlated Electrons · Physics 2025-10-27 Yi Yang , Yayun Hu , Zi-Xiang Hu