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Given the ground state wavefunction for an interacting lattice model, we define a "correlation density matrix"(CDM) for two disjoint, separated clusters $A$ and $B$, to be the density matrix of their union, minus the direct product of their…

Strongly Correlated Electrons · Physics 2013-05-29 Siew-Ann Cheong , C. L. Henley

A microscopic method for calculating nuclear level density (NLD) based on the covariant density functional theory (CDFT) is developed. The particle-hole state density is calculated by combinatorial method using the single-particle levels…

Nuclear Theory · Physics 2023-09-27 Kun-Peng Geng , Peng-Xiang Du , Jian Li , Dong-Liang Fang

Existing latent diffusion models typically couple scale with content complexity, using more latent tokens to represent higher-resolution images or higher-frame rate videos. However, the latent capacity required to represent visual data…

Computer Vision and Pattern Recognition · Computer Science 2025-11-21 Tianxiong Zhong , Xingye Tian , Xuebo Wang , Boyuan Jiang , Xin Tao , Pengfei Wan

We present a comparative study of numerical methods for computingelectronic densities of states (DOS) in periodic systems. We provide a detailed analysis of the domain of validity of the Brillouincomplex deformation (BCD), a…

Numerical Analysis · Mathematics 2026-04-01 Ewen Lallinec , Antoine Levitt

We propose the DPSM method, a density-based node clustering approach that automatically determines the number of clusters and can be applied in both data space and graph space. Unlike traditional density-based clustering methods, which…

Machine Learning · Computer Science 2024-11-05 Feiping Nie , Yitao Song , Jingjing Xue , Rong Wang , Xuelong Li

Quantum resonances, i.e., metastable states with a finite lifetime, play an important role in nuclear physics and other domains. Describing this phenomenon theoretically is generally a challenging task. In this work, we combine two…

Nuclear Theory · Physics 2024-05-17 Hang Yu , Nuwan Yapa , Sebastian König

In the molecular quantum chemistry community, coupled-cluster (CC) methods are well-recognized for their systematic convergence and reliability. The extension of the theory to extended systems has been comparably recent, so that…

Chemical Physics · Physics 2024-10-31 Andreas Grüneis , Evgeny Moerman , Matthias Scheffler , Tonghao Shen , Igor Ying Zhang

We introduce a numerical method for computing spectral densities, and apply it to the evaluation of the local density of states (LDOS) of sparse Hamiltonians derived from tight-binding models. The approach, which we call the high-order…

Computational Physics · Physics 2025-12-04 Jinjing Yi , Daniel Massatt , Andrew Horning , Mitchell Luskin , J. H. Pixley , Jason Kaye

The knowledge of the nuclear level density is necessary for understanding various reactions including those in the stellar environment. Usually the combinatorics of Fermi-gas plus pairing is used for finding the level density. Recently a…

Nuclear Theory · Physics 2016-06-22 Roman Sen'kov , Vladimir Zelevinsky

A quantum-mechanical calculation of the single-particle level (s.p.l.) density $g(\epsilon)$ is carried on by using the connection with the single-particle Green's function. The relation between the imaginary part of Green's function and…

Nuclear Theory · Physics 2007-05-23 I. Stetcu

We propose a method to calculate the QCD level density directly from the thermodynamic quantities obtained by lattice QCD simulations with the use of the maximum entropy method (MEM). Understanding QCD thermodynamics from QCD spectral…

High Energy Physics - Lattice · Physics 2007-05-23 Shinji Ejiri , Tetsuo Hatsuda

The Half-Space Matching (HSM) method has recently been developed as a new method for the solution of 2D scattering problems with complex backgrounds, providing an alternative to Perfectly Matched Layers (PML) or other artificial boundary…

The Dead Leaves Model (DLM) provides a random tessellation of $d$-space, representing the visible portions of fallen leaves on the ground when $d=2$. For $d=1$, we establish formulae for the intensity, two-point correlations, and asymptotic…

Probability · Mathematics 2020-04-14 Mathew D. Penrose

The modern form of the Moments Method applied to the calculation of the nuclear shell-model level density is explained and examples of the method at work are given. The calculated level density practically exactly coincides with the result…

Nuclear Theory · Physics 2016-01-27 V. Zelevinsky , M. Horoi , R. A. Sen'kov

The coupled cluster method (CCM) is a powerful and widely applied technique of modern-day quantum many-body theory. It has been used with great success in order to understand the properties of quantum magnets at zero temperature. This is…

Strongly Correlated Electrons · Physics 2009-09-11 D. J. J. Farnell

With the goal of measuring localization in disordered interacting systems, we examine the finite-size scaling of the geometrically-averaged density of states calculated from the local Green's function with finite energy resolution. Our…

Strongly Correlated Electrons · Physics 2009-11-13 R. Wortis , Yun Song , W. A. Atkinson

We present a new generic approach to the condensed-matter ground-state problem which is complementary to variational techniques and works directly in the thermodynamic limit. Relaxing the ground-state problem, we obtain semidefinite…

Strongly Correlated Electrons · Physics 2012-08-08 Thomas Barthel , Robert Hübener

Different densities of electromagnetic states inside a one dimensional photonic crystal (1D PC) are studied. Hertz vector formalism is used to calculate Green tensor inside a layered structure, semi-analytically. Based on the obtained Green…

Optics · Physics 2022-03-18 Ebrahim Forati

The relationship between the spectral density and free energy of a spin system is considered. The analytical expressions allowing for the calculation of the spectral density for solvable models are determined. A linear Ising model is taken…

Disordered Systems and Neural Networks · Physics 2017-04-06 B. V. Kryzhanovsky

We propose a continuous-time formulation of persistent contrastive divergence (PCD) for maximum likelihood estimation (MLE) of unnormalised densities. Our approach expresses PCD as a coupled, multiscale system of stochastic differential…

Machine Learning · Statistics 2025-10-03 Paul Felix Valsecchi Oliva , O. Deniz Akyildiz , Andrew Duncan