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The so-called block-term decomposition (BTD) tensor model has been recently receiving increasing attention due to its enhanced ability of representing systems and signals that are composed of \emph{blocks} of rank higher than one, a…

Numerical Analysis · Mathematics 2021-04-21 Athanasios A. Rontogiannis , Eleftherios Kofidis , Paris V. Giampouras

Exceptional points~(EPs) appear as degeneracies in the spectrum of non-Hermitian matrices at which the eigenvectors coalesce. In general, an EP of order $n$ may find room to emerge if $2(n-1)$ real constraints are imposed. Our results show…

Quantum Physics · Physics 2022-07-29 Sharareh Sayyad , Flore K. Kunst

Efficient methods for encoding and compression are likely to pave way towards the problem of efficient trainability on higher dimensional Hilbert spaces overcoming issues of barren plateaus. Here we propose an alternative approach to…

Quantum Physics · Physics 2022-09-30 Raja Selvarajan , Manas Sajjan , Travis S. Humble , Sabre Kais

Fractional equations have become the model of choice in several applications where heterogeneities at the microstructure result in anomalous diffusive behavior at the macroscale. In this work we introduce a new fractional operator…

Numerical Analysis · Mathematics 2021-01-29 Marta D'Elia , Christian Glusa

The pseudo--spectral decomposition of an $N$--particle antisymmetric 1--body positive--semidefinite operator that corresponds to the canonical convex decomposition into the extreme elements of the dual cone of the set of fermion…

Quantum Physics · Physics 2009-10-28 Hubert Grudzinski

We study strong hyperbolicity of first order partial differential equations for systems with differential constraints. In these cases, the number of equations is larger than the unknown fields, therefore, the standard Kreiss necessary and…

General Relativity and Quantum Cosmology · Physics 2021-11-17 Fernando Abalos

Rendering highly scattering participating media using brute force path tracing is a challenge. The diffusion approximation reduces the problem to solving a simple linear partial differential equation. Flux-limited diffusion introduces…

Graphics · Computer Science 2018-07-03 David Koerner , Jamie Portsmouth , Wenzel Jakob

Many living and physical systems such as cell aggregates, tissues or bacterial colonies behave as unconventional systems of particles that are strongly constrained by volume exclusion and shape interactions. Understanding how these…

Quantitative Methods · Quantitative Biology 2026-05-20 Antoine Diez , Jean Feydy

Nonlocal strain gradient continuum mechanics is a methodology widely employed in literature to assess size effects in nanostructures. Notwithstanding this, improper higher-order boundary conditions (HOBC) are prescribed to close the…

Classical Physics · Physics 2020-04-22 R. Barretta , S. Ali Faghidian , F. Marotti de Sciarra , M. S. Vaccaro

We show the existence of global minimizers for a geometrically nonlinear isotropic elastic Cosserat 6-parameter shell model. The proof of the main theorem is based on the direct methods of the calculus of variations using essentially the…

Analysis of PDEs · Mathematics 2020-09-16 Ionel-Dumitrel Ghiba , Mircea Bîrsan , Peter Lewintan , Patrizio Neff

In this paper, we focus on model reduction of biomolecular systems with multiple time-scales, modeled using the Linear Noise Approximation. Considering systems where the Linear Noise Approximation can be written in singular perturbation…

Dynamical Systems · Mathematics 2016-09-27 Narmada Herath , Domitilla Del Vecchio

We analyze two reduction methods for nonholonomic systems that are invariant under the action of a Lie group on the configuration space. Our approach for obtaining the reduced equations is entirely based on the observation that the dynamics…

Differential Geometry · Mathematics 2011-05-02 M. Crampin , T. Mestdag

We present a simple two-dimensional model of the indirect dissociative recombination process. The model has one electronic and one nuclear degree of freedom and it can be solved to high precision, without making any physically motivated…

The two-dimensional Hubbard model is studied for small values of the interaction strength (U of the order of the hopping amplitude t), using a variational ansatz well suited for this regime. The wave function, a refined Gutzwiller ansatz,…

Superconductivity · Physics 2019-07-19 Dionys Baeriswyl

A simple variant of the BDDC preconditioner in which constraints are imposed on a selected set of subobjects (subdomain subedges, subfaces and vertices between pairs of subedges) is presented. We are able to show that the condition number…

Numerical Analysis · Mathematics 2020-01-22 Santiago Badia , Alberto F. Martín , Hieu Nguyen

We use vortex matter in type-II superconductors as a playground to study how different types of disorder affect the long wavelength density fluctuations of the system. We find that irrespective of the vortex-vortex interaction, in the case…

Superconductivity · Physics 2023-06-21 Joaquín Puig , Jazmín Aragón Sánchez , Gladys Nieva , Alejandro B. Kolton , Yanina Fasano

There is a tendency to write the equations of general relativity as a first order symmetric system of time dependent partial differential equations. However, for numerical reasons, it might be advantageous to use a second order formulation…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Heinz-O. Kreiss , Omar E. Ortiz

We prove the existence of solutions of a cross-diffusion parabolic population problem. The system of partial differential equations is deduced as the limit equations satisfied by the densities corresponding to an interacting particles…

Analysis of PDEs · Mathematics 2024-01-29 Gonzalo Galiano , Virginia Selgas

We present a new and simple bound for the exponential decay of second order systems using the spectral shift. This result is applied to finite matrices as well as to partial differential equations of Mathematical Physics. The type of the…

Spectral Theory · Mathematics 2016-08-16 Krešimir Veselić

We extend a new treatment proposed for two-nucleon (2N) and three-nucleon (3N) bound states to 2N scattering. This technique takes momentum vectors as variables, thus, avoiding partial wave decomposition, and handles spin operators…

Nuclear Theory · Physics 2010-05-17 I. Fachruddin , Ch. Elster , J. Golak , R. Skibinski , W. Gloeckle , H. Witala