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Finite temperature density functional theory requires representations for the internal energy, entropy, and free energy as functionals of the local density field. A central formal difficulty for an orbital-free representation is…

Statistical Mechanics · Physics 2011-05-12 James W. Dufty , S. B. Trickey

Fractional differential equations are powerful mathematical descriptors for intricate physical phenomena in a compact form. However, compared to integer ordinary or partial differential equations, solving fractional differential equations…

Analysis of PDEs · Mathematics 2025-06-16 Donya Dabiri , Joshua DaRosa , Milad Saadat , Deepak Mangal , Safa Jamali

In many areas of engineering, nonlinear numerical analysis is playing an increasingly important role in supporting the design and monitoring of structures. Whilst increasing computer resources have made such formerly prohibitive analyses…

Numerical Analysis · Mathematics 2020-07-02 Thomas Simpson , Nikolaos Dervilis , Eleni Chatzi

We give a descriptive review of the Fermionic basis approach to the theory of correlation functions of the XXZ quantum spin chain. The emphasis is on explicit formulae for short-range correlation functions which will be presented in a way…

Statistical Mechanics · Physics 2021-09-22 Frank Göhmann , Raphael Kleinemühl , Alexander Weiße

Recently, we introduced (e-print arXiv:1407.7128) {\em local reduced density matrix functional theory} (local RDMFT), a theoretical scheme capable of incorporating static correlation effects in Kohn-Sham equations. Here, we apply local…

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

We analyze the many-particle Schrodinger equation for fermions in a thermal ensemble by introducing an exponential operator expansion, defined in the context of thermofield dynamics. The expansion is optimized variationally at each time…

Statistical Mechanics · Physics 2020-01-10 Edward B. Baker

Time-dependent orbital-free DFT is an efficient method for calculating the dynamic properties of large scale quantum systems due to the low computational cost compared to standard time-dependent DFT. We formalize this method by mapping the…

Chemical Physics · Physics 2021-06-09 Kaili Jiang , Michele Pavanello

Among the variational wave functions for Fermionic Hamiltonians, neural network backflow (NNBF) and hidden fermion determinant states (HFDS) are two prominent classes to provide accurate approximations to the ground state. Here we develop a…

Disordered Systems and Neural Networks · Physics 2024-11-18 Zejun Liu , Bryan K. Clark

Nucleation is very common physical phenomena that occur at the microscopic scale. However, due to the presence of nucleation barriers, the time scale of nucleation is usually much longer than that of microscopic particle dynamics. These…

Chemical Physics · Physics 2023-08-08 Zihao Bai

In a recent work, we introduced the foundations of an orthogonally constrained complete active space self-consistent field (OC-CASSCF) framework that produces state-specific molecular orbitals for mutually orthogonal multiconfigurational…

Chemical Physics · Physics 2026-01-28 Loris Delafosse , Vincent Robert , Saad Yalouz

Over the past decade we have developed Koopmans functionals, a computationally efficient approach for predicting spectral properties with an orbital-density-dependent functional framework. These functionals impose a generalized piecewise…

The concept of near resonances for harmonic approximations of semiclassical Schr\"odinger operators is introduced and explored. Combined with a natural extension of the Birkhoff-Gustavson normal form, we obtain formulas for approaching the…

Spectral Theory · Mathematics 2024-10-16 Abdelkader Bourebai , Kaoutar Ghomari , San Vu Ngoc

The main purpose of this review is to summarize the recent advances of the Conservation-Dissipation Formalism (CDF), a new way for constructing both thermodynamically compatible and mathematically stable and well-posed models for…

Mathematical Physics · Physics 2021-11-24 Liangrong Peng , Liu Hong

We study the close connection between rational functions that approximate a given Boolean function, and quantum algorithms that compute the same function using postselection. We show that the minimal degree of the former equals (up to a…

Quantum Physics · Physics 2014-08-26 Urmila Mahadev , Ronald de Wolf

Quantum corrections to Thomas-Fermi (TF) theory are investigated for noninteracting one-dimensional fermions with known uniform semiclassical approximations to the density and kinetic energy. Their structure is analyzed, and contributions…

Quantum Gases · Physics 2017-03-15 Raphael F. Ribeiro , Kieron Burke

Molecule-optimized basis sets, based on approximate natural orbitals, are developed for accelerating the convergence of quantum calculations with strongly correlated (multi-referenced) electrons. We use a low-cost approximate solution of…

Chemical Physics · Physics 2014-02-12 Gergely Gidofalvi , David A. Mazziotti

We introduce an efficient finite-element approach for large-scale real-space pseudopotential density functional theory (DFT) calculations incorporating noncollinear magnetism and spin-orbit coupling. The approach, implemented within the…

Materials Science · Physics 2025-06-11 Nikhil Kodali , Phani Motamarri

We have explained and comprehensively illustrated in Part I that the generalized Pauli constraints suggest a natural extension of the concept of active spaces. In the present Part II, we provide rigorous derivations of the theorems involved…

Quantum Physics · Physics 2020-03-23 Tomasz Maciążek , Adam Sawicki , David Gross , Alexandre Lopes , Christian Schilling

Nuclear matter is studied within the Density Functional Theory (DFT) framework. Our method employs a finite number of nucleons in a box subject to periodic boundary conditions, in order to simulate infinite matter and study its response to…

Nuclear Theory · Physics 2023-04-26 Francesco Marino , Gianluca Colò , Xavier Roca-Maza , Enrico Vigezzi

In this paper, we solve a set of hierarchy equations for the reduced statistical density operator in a grand canonical ensemble for an identical many-body fermion system without or with two-body interaction. We take the single-particle…

Statistical Mechanics · Physics 2009-11-10 Liqiang Wei , Chiachung Sun
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