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Understanding mechanisms for energy dissipation from nanoparticles in contact with large samples is a central problem in describing friction microscopically. Calculation of the reduced density matrix appears to be the most suitable metho to…

Condensed Matter · Physics 2015-06-25 A. Ozpineci , D. M. Leitner , S. Ciraci

The Reduced Density Matrix Functional Theory (RDMFT) is a remarkable tool for studying properties of ground states of strongly interacting quantum many body systems. As it gives access to the one-particle reduced density matrix of the…

Quantum Gases · Physics 2021-10-20 Tomasz Maciążek

Reduced density-matrix functional theory (RDMFT) has become an appealing alternative to density-functional theory to describe electronic properties of highly-correlated systems. Here we derive exact conditions for the suitability of RDMFT…

Strongly Correlated Electrons · Physics 2012-04-19 A. Putaja , E. Rasanen

In this talk we go over several new developments regarding the techniques for a large class of non-hermitian matrix models with unitary randomness (complex random numbers). In particular, we discuss: (a) - A diagrammatic approach based on a…

High Energy Physics - Phenomenology · Physics 2008-02-03 Romuald A. Janik , Maciej A. Nowak , Gabor Papp , Ismail Zahed

The possible spectra of one-particle reduced density matrices that are compatible with a pure multipartite quantum system of finite dimension form a convex polytope. We introduce a new construction of inner- and outer-bounding polytopes…

Mathematical Physics · Physics 2017-12-27 Tomasz Maciazek , Valdemar Tsanov

We propose a regularization scheme for image reconstruction that leverages the power of deep learning while hinging on classic sparsity-promoting models. Many deep-learning-based models are hard to interpret and cumbersome to analyze…

Image and Video Processing · Electrical Eng. & Systems 2024-07-10 Mehrsa Pourya , Sebastian Neumayer , Michael Unser

We address combinatorial problems that can be formulated as minimization of a partially separable function of discrete variables (energy minimization in graphical models, weighted constraint satisfaction, pseudo-Boolean optimization, 0-1…

Computer Vision and Pattern Recognition · Computer Science 2015-05-05 Alexander Shekhovtsov

A phenomenological method based on the natural orbital representation is applied to construct the ground state one-body density matrix which describes correctly both density and momentum distributions in $^{4}He$, $^{16}O$ and $^{40}Ca$…

The simulation of a short fibre reinforced structure by means of the FEM requires the knowledge of the material behaviour at every Gauss point. In order to obtain such information, a representative volume element (RVE) containing…

Materials Science · Physics 2014-08-21 N. Goldberg , H. Donner , J. Ihlemann

A central problem in algebraic complexity, posed by J. Edmonds, asks to decide if the span of a given $l$-tuple $\V=(\V_1, \ldots, \V_l)$ of $N \times N$ complex matrices contains a non-singular matrix. In this paper, we provide a quiver…

Representation Theory · Mathematics 2020-09-01 Calin Chindris , Daniel Kline

Partial differential equations (PDEs) with near singular solutions pose significant challenges for traditional numerical methods, particularly in complex geometries where mesh generation and adaptive refinement become computationally…

Numerical Analysis · Mathematics 2025-07-24 Yangtao Deng , Qiaolin He , Xiaoping Wang

Many electronic structure methods rely on the minimization of the energy of the system with respect to the one-body reduced density matrix (1-RDM). To formulate a minimization algorithm, the 1-RDM is often expressed in terms of its…

Chemical Physics · Physics 2025-04-18 Nicolas Cartier , Klaas Giesbertz

In this article, we present a set of hierarchy Bloch equations for the reduced density operators in either canonical or grand canonical ensembles in the occupation number representation. They provide a convenient tool for studying the…

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

Recovered finite element methods (R-FEM) have been recently introduced for meshes consisting of simplicial and/or box-type meshes. Here, utilising the flexibility of R-FEM framework, we extend their definition on polygonal and polyhedral…

Numerical Analysis · Mathematics 2018-04-24 Zhaonan Dong , Emmanuil H. Georgoulis , Tristan Pryer

We present a generalized framework, renormalized density matrix downfolding (RDMD), to derive systematically improvable, highly accurate, and nonperturbative effective models from ab initio calculations. This framework moves beyond the…

Strongly Correlated Electrons · Physics 2025-02-27 Yueqing Chang , Sonali Joshi , Lucas K. Wagner

Revisiting the issue associated with Position-Dependent Mass (PDM), we reaffirm that the appropriate framework for addressing a generic PDM is the symmetrization proposed by BenDaniel and Duke. To accomplish this result adopts the effective…

Quantum Physics · Physics 2025-01-09 F. C. E. Lima , F. M. Belchior , C. A. S. Almeida

We numerically study the random-hopping fermions (the Cruetz ladder) with repulsion and investigate how the interactions deform localized eigenstates by means of the one particle-density matrix (OPDM). The ground state exhibits resurgence…

Disordered Systems and Neural Networks · Physics 2022-03-14 Takahiro Orito , Yoshihito Kuno , Ikuo Ichinose

At the core of any inference procedure in deep neural networks are dot product operations, which are the component that require the highest computational resources. A common approach to reduce the cost of inference is to reduce its memory…

Machine Learning · Computer Science 2018-12-19 Simon Wiedemann , Klaus-Robert Müller , Wojciech Samek

This work proposes an $r$-adaptive finite element method (FEM) using neural networks (NNs). The method employs the Ritz energy functional as the loss function, currently limiting its applicability to symmetric and coercive problems, such as…

The affine rank minimization problem consists of finding a matrix of minimum rank that satisfies a given system of linear equality constraints. Such problems have appeared in the literature of a diverse set of fields including system…

Optimization and Control · Mathematics 2010-08-09 Benjamin Recht , Maryam Fazel , Pablo A. Parrilo