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Semiclassical electrodynamics is an appealing approach for studying light-matter interactions, especially for realistic molecular systems. However, there is no unique semiclassical scheme. On the one hand, intermolecular interactions can be…

Chemical Physics · Physics 2019-12-16 Tao E. Li , Hsing-Ta Chen , Abraham Nitzan , Joseph E. Subotnik

We construct effective Hamiltonians which despite their apparently nonrelativistic form incorporate relativistic effects by involving parameters which depend on the relevant momentum. For some potentials the corresponding energy eigenvalues…

High Energy Physics - Phenomenology · Physics 2016-09-01 Wolfgang LUCHA , Franz F. SCHÖBERL

Measuring the Hamiltonian of dipolar coupled spin systems is usually a difficult task due to the high complexity of their spectra. Currently, molecules with unknown geometrical structure and low symmetry are extremely tedious or impossible…

Quantum Physics · Physics 2013-12-10 Denis-Alexandre Trottier , Virginia Jauregui-Villanueva , Jingfu Zhang

Machine learning models now influence decisions that directly affect people's lives, making it important to understand not only their predictions, but also how individuals could act to obtain better results. Algorithmic recourse provides…

Machine Learning · Computer Science 2026-02-10 Bohdan Turbal , Iryna Voitsitska , Lesia Semenova

We present a Reinforcement Learning-based Robust Nonlinear Model Predictive Control (RL-RNMPC) framework for controlling nonlinear systems in the presence of disturbances and uncertainties. An approximate Robust Nonlinear Model Predictive…

Systems and Control · Electrical Eng. & Systems 2021-04-08 Hossein Nejatbakhsh Esfahani , Arash Bahari Kordabad , Sebastien Gros

We present two approaches for enhancing the accuracy of second order finite difference approximations of two-dimensional semilinear parabolic systems. These are the fourth order compact difference scheme and the fourth order scheme based on…

Numerical Analysis · Mathematics 2017-01-12 Ivan Dimov , Juri Kandilarov , Venelin Todorov , Lubin Vulkov

Gradient descent methods are fundamental first-order optimization algorithms in both Euclidean spaces and Riemannian manifolds. However, the exact gradient is not readily available in many scenarios. This paper proposes a novel inexact…

Optimization and Control · Mathematics 2024-09-18 Juan Zhou , Kangkang Deng , Hongxia Wang , Zheng Peng

The auxiliary-field quantum Monte Carlo (AFQMC) method is a general numerical method for correlated many-electron systems, which is being increasingly applied in lattice models, atoms, molecules, and solids. Here we introduce the theory and…

Computational Physics · Physics 2021-02-24 Hao Shi , Shiwei Zhang

The Hamiltonian Monte Carlo (HMC) method allows sampling from continuous densities. Favorable scaling with dimension has led to wide adoption of HMC by the statistics community. Modern auto-differentiating software should allow more…

Computation · Statistics 2022-08-17 Ian Langmore , Michael Dikovsky , Scott Geraedts , Peter Norgaard , Rob von Behren

A new multidimensional simulation code for relativistic two-fluid electrodynamics (RTFED) is described. The basic equations consist of the full set of Maxwell's equations coupled with relativistic hydrodynamic equations for separate two…

High Energy Astrophysical Phenomena · Physics 2016-11-09 Takanobu Amano

Relativistic corrections to the evolution of structure can be used to test general relativity on cosmological scales. They are also a well-known systematic contamination in the search for a primordial non-Gaussian signal. We present a…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-28 J. Adamek , J. Calles , T. Montandon , J. Noreña , C. Stahl

By revisiting the path-integral formulation of the Hubbard model, we propose a theoretical approach based on a semiclassical approximation employing an unconventional coherent-state representation. Within this framework, a subset of the…

Strongly Correlated Electrons · Physics 2026-04-06 Yuki Yamasaki , Hidemaro Suwa , Cristian D. Batista , Shintaro Hoshino

In this note, we propose a symplectic algorithm for the stable manifolds of the Hamilton-Jacobi equations combined with an iterative procedure in [Sakamoto-van~der Schaft, IEEE Transactions on Automatic Control, 2008]. Our algorithm…

Optimization and Control · Mathematics 2021-08-16 Guoyuan Chen , Gaosheng Zhu

Robotic affordance estimation is challenging due to visual, geometric, and semantic ambiguities in sensory input. We propose a method that disambiguates these signals using two coupled recursive estimators for sub-aspects of affordances:…

Robotics · Computer Science 2026-03-17 Patrick Lowin , Vito Mengers , Oliver Brock

We introduce ABEL, the Adaptable Beginning-to-End Linac simulation framework developed for agile design studies of plasma-based accelerators and colliders. ABEL's modular architecture allows users to simulate particle acceleration across…

Accelerator Physics · Physics 2025-07-09 J. B. B. Chen , E. Adli , P. Drobniak , O. G. Finnerud , E. Hørlyk , D. Kalvik , C. A. Lindstrøm , F. Peña , K. Sjobak

We develop a sensitivity function for the design of electron optics using an adjoint approach based on a form of reciprocity implicit in Hamilton's equations of motion. The sensitivity function, which is computed with a small number of…

Accelerator Physics · Physics 2018-07-24 Thomas M. Antonsen , David Chernin , John Petillo

We propose a novel approach to approximate Bayesian computation (ABC) that seeks to cater for possible misspecification of the assumed model. This new approach can be equally applied to rejection-based ABC and to popular regression…

Methodology · Statistics 2020-08-11 David T. Frazier , Christopher Drovandi , Ruben Loaiza-Maya

Hyperdimensional Computing (HDC) offers a computationally efficient paradigm for neuromorphic learning. Yet, it lacks rigorous uncertainty quantification, leading to open decision boundaries and, consequently, vulnerability to outliers,…

We present the new recombination code HYREC-2, holding the same accuracy as the state-of-the-art codes HYREC and COSMOREC and, at the same time, surpassing the computational speed of the code RECFAST commonly used for CMB-anisotropy data…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-22 Nanoom Lee , Yacine Ali-Haïmoud

We consider non-Hermitian tight-binding one-dimensional Hamiltonians and show that imposing a certain symmetry causes all eigenvalues to pair up and the corresponding eigenstates to coalesce in pairs. This Pairwise Coalescence (PC) is an…

Quantum Physics · Physics 2026-02-26 Yusuf H. Erdogan , Masudul Haque