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One of the major computational bottlenecks in one-body reduced density matrix (1RDM) functional theory is the evaluation of approximate 1RDM functionals and their derivatives. The reason is that more advanced approximate functionals are…

Computational Physics · Physics 2016-02-15 Klaas J. H. Giesbertz

One of the most used approaches in simulating materials is the tight-binding approximation. When using this method in a material simulation, it is necessary to compute the eigenvalues and eigenvectors of the Hamiltonian describing the…

Numerical Analysis · Computer Science 2009-10-29 Matthias Petschow , Edoardo Di Napoli , Paolo Bientinesi

Simulation of quantum chemistry is expected to be a principal application of quantum computing. In quantum simulation, a complicated Hamiltonian describing the dynamics of a quantum system is decomposed into its constituent terms, where the…

Quantum Physics · Physics 2020-03-04 Yingkai Ouyang , David R. White , Earl T. Campbell

We present an analytical study of the spatial decay rate $\gamma$ of the one-particle density matrix $\rho(\vec r,\vec r')\sim\exp(-\gamma|\vec r-\vec r'|)$ for systems described by single particle orbitals in periodic potentials in…

Materials Science · Physics 2007-05-23 Sohrab Ismail-Beigi , Tomas Arias

We demonstrate the power of a first principle-based and practicable method that allows for the perturbative computation of reduced density matrix elements of an open quantum system without making use of any master equations. The approach is…

High Energy Physics - Theory · Physics 2023-06-12 Christian Käding , Mario Pitschmann

We study the matrix completion problem when the observation pattern is deterministic and possibly non-uniform. We propose a simple and efficient debiased projection scheme for recovery from noisy observations and analyze the error under a…

Information Theory · Computer Science 2019-10-31 Simon Foucart , Deanna Needell , Reese Pathak , Yaniv Plan , Mary Wootters

This research presents a novel depth estimation algorithm based on a Transformer-encoder architecture, tailored for the NYU and KITTI Depth Dataset. This research adopts a transformer model, initially renowned for its success in natural…

Computer Vision and Pattern Recognition · Computer Science 2024-06-25 Linhan Xia , Junbang Liu , Tong Wu

Robust point-set registration in the presence of noise and outliers is challenging because the matched points (inliers) must be identified before reliable alignment can be performed. Existing robust registration methods typically optimize…

Methodology · Statistics 2026-05-15 Ruizi Wu , Yuehaw Khoo , Wanjie Wang

The self-consistent evaluation of Hubbard parameters using linear-response theory is crucial for quantitatively predictive calculations based on Hubbard-corrected density-functional theory. Here, we extend a recently-introduced approach…

Materials Science · Physics 2021-02-02 Iurii Timrov , Nicola Marzari , Matteo Cococcioni

The last decade has seen a large increase in the number of electronic-structure calculations that involve adding a Hubbard term to the local density approximation band-structure Hamiltonian. The Hubbard term is then solved either at the…

Strongly Correlated Electrons · Physics 2009-08-25 R. C. Albers , N. E. Christensen , A. Svane

An approximation for the exchange-correlation energy of reduced-density-matrix-functional theory was recently derived from a study of the homogeneous electron gas (N.N. Lathiotakis, N. Helbig, E.K.U. Gross, Phys. Rev. B 75, 195120 (2007)).…

Strongly Correlated Electrons · Physics 2009-11-13 N. N. Lathiotakis , N. Helbig , A. Zacarias , E. K. U. Gross

Reduced basis methods are popular for approximately solving large and complex systems of differential equations. However, conventional reduced basis methods do not generally preserve conservation laws and symmetries of the full order model.…

Numerical Analysis · Mathematics 2018-03-20 Babak Maboudi Afkham , Jan S. Hesthaven

The accurate determination of magnetic phase transitions in electronic systems is an important task of solid state theory. While numerically exact results are readily available for model systems such as the half-filled 3D Hubbard model, the…

Strongly Correlated Electrons · Physics 2022-01-19 Sergei Iskakov , Emanuel Gull

Based on the standard many-fermion field theory, the authors construct models describing ultracold fermions in a 1D optical lattices by implementing a mode expansion of the fermionic field operator where modes, in addition to space…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Francesco Massel , Vittorio Penna

We present a new paradigm for speeding up randomized computations of several frequently used functions in machine learning. In particular, our paradigm can be applied for improving computations of kernels based on random embeddings. Above…

Machine Learning · Statistics 2016-04-26 Krzysztof Choromanski , Francois Fagan

We present a new and efficient optimization method to determine the structure of disordered systems in agreement with available experimental data. Our approach permits the application of accurate electronic structure calculations within the…

Materials Science · Physics 2014-06-23 Jan H. Los , Thomas D. Kühne

During the noisy intermediate-scale quantum (NISQ) era, it is important to optimize the quantum circuits in circuit depth and gate count, especially entanglement gates, including the CNOT gate. Among all the unitary operators, diagonal…

Quantum Physics · Physics 2024-04-15 Xinchi Huang , Taichi Kosugi , Hirofumi Nishi , Yu-ichiro Matsushita

This work focuses on optimizing the gates of a quantum circuit with a given topology to approximate the unitary time evolution governed by a Hamiltonian. Recognizing that unitary matrices form a mathematical manifold, we employ Riemannian…

Quantum Physics · Physics 2025-07-01 Fabian Putterer , Max M. Zumpe , Isabel Nha Minh Le , Qunsheng Huang , Christian B. Mendl

In this work we develop and analyze an adaptive finite element method for efficiently solving electrical impedance tomography -- a severely ill-posed nonlinear inverse problem for recovering the conductivity from boundary voltage…

Numerical Analysis · Mathematics 2019-05-16 Bangti Jin , Yifeng Xu , Jun Zou

For any torsion-free hyperbolic group $\Gamma$ and any group $G$ that is fully residually $\Gamma$, we construct algorithmically a finite collection of homomorphisms from $G$ to groups obtained from $\Gamma$ by extensions of centralizers,…

Group Theory · Mathematics 2013-02-12 Olga Kharlampovich , Jeremy Macdonald
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