Numerical Methods and Theoretical Frameworks for Complex Systems

Current Developments in the Research Area

The recent advancements in the research area have shown a significant shift towards the development and application of innovative numerical methods and theoretical frameworks. The field is witnessing a convergence of ideas from various disciplines, leading to the creation of more robust, efficient, and versatile computational tools. Here are the key trends and developments:

  1. Thermodynamically Consistent Models: There is a growing emphasis on developing models that are thermodynamically consistent, ensuring that they adhere to the principles of thermodynamics. This includes the modification of classical models to include reverse reactions and virtual species, transforming them into closed systems. These models are being numerically studied to understand pattern formation and stability, particularly in systems with small parameters related to reaction rates.

  2. High-Order Numerical Schemes: The development of high-order numerical schemes, particularly for complex systems like plasmas and nonlinear optical media, is a significant focus. These schemes aim to handle the quasineutral limit and other challenging regimes where standard methods fail. The introduction of penalized IMEX Runge-Kutta methods and Hamiltonian structure-preserving discretizations are notable advancements in this direction.

  3. Algebraic and Information-Theoretic Approaches: There is a surge in the use of algebraic representations and information-theoretic quantities to refine existing frameworks and develop new ones. These approaches are being applied to characterize entropy, fixed-parity information quantities, and other critical metrics, leading to deeper insights and more accurate representations.

  4. Stochastic Differential Equations (SDEs): The study of SDEs, especially those with multiplicative noise, is progressing with the development of error estimates under relative entropy. This work is crucial for understanding the sharp error bounds in various distances, such as total variation and Wasserstein distances, and is paving the way for more accurate numerical methods.

  5. Eigenvalue and Eigenpair Computations: Advances in computing eigenpairs of large-scale matrices, particularly skew-symmetric and Hermitian matrices, are being made. The introduction of power-like methods and adaptive strategies for adjusting block sizes dynamically is enhancing computational efficiency and convergence speed.

  6. Sampling Recovery and Parametric PDEs: The convergence rates of sampling recovery methods for functions in Bochner spaces are being explored, with applications to parametric PDEs and infinite-dimensional holomorphic functions. These studies are significantly improving the known results and providing more efficient approximation techniques.

  7. Variational Multiscale Methods: The extension of Variational Multiscale (VMS) methods to the discrete level is a notable development. These methods are being applied to steady linear problems, with a focus on optimal solutions and the use of optimal projectors to approximate unresolved scales.

  8. Coupling Strategies and Relaxation Approaches: New coupling strategies and relaxation approaches are being developed for systems involving two-phase fluids and linear-elastic solids. These methods are being applied to complex problems like collapsing vapor bubbles and are showing promising results in one-dimensional simulations.

  9. Divergence-Free Projection Methods: The introduction of divergence-free projection methods for quasiperiodic photonic crystals is a significant advancement. These methods transform the original Maxwell's system into a periodic one in higher dimensions, enabling efficient numerical approximations.

  10. Asymptotic Preserving Schemes: The development of asymptotic preserving schemes for low Mach number isentropic Euler equations is another key area of focus. These schemes aim to respect the transition property from compressible to incompressible systems, ensuring accuracy and stability.

Noteworthy Papers

  1. "On pattern formation in the thermodynamically-consistent variational Gray-Scott model": This paper introduces a thermodynamically consistent Gray-Scott model, stabilizing stationary patterns and admitting oscillated and traveling-wave-like patterns.

  2. "High order Asymptotic Preserving penalized numerical schemes for the Euler-Poisson system in the quasi-neutral limit": The paper presents high-order IMEX finite volume methods for plasmas, ensuring uniform stability and high-order accuracy in the quasineutral limit.

  3. "A Hamiltonian structure-preserving discretization of Maxwell's equations in nonlinear media": This work introduces a finite element discretization that is energy-stable and exactly conserves Gauss's laws, making it suitable for a broad class of nonlinear optical problems.

  4. "Algebraic Representations of Entropy and Fixed-Parity Information Quantities": The paper refines the signed measure space for entropy and demonstrates its capability to represent various information quantities, including fixed-parity expressions.

  5. "Error estimates of the Euler's method for stochastic differential equations with multiplicative noise via relative entropy": This study provides sharp error bounds for the Euler-Maruyama discretization of SDEs with multiplicative noise, using relative entropy as the foundation.

These papers represent significant strides in their respective subfields and contribute to the broader

Sources

On pattern formation in the thermodynamically-consistent variational Gray-Scott model

High order Asymptotic Preserving penalized numerical schemes for the Euler-Poisson system in the quasi-neutral limit

A Hamiltonian structure-preserving discretization of Maxwell's equations in nonlinear media

Algebraic Representations of Entropy and Fixed-Parity Information Quantities

Error estimates of the Euler's method for stochastic differential equations with multiplicative noise via relative entropy

A Power-like Method for Computing the Dominant Eigenpairs of Large Scale Real Skew-Symmetric Matrices

Sampling recovery in Bochner spaces and applications to parametric PDEs with random inputs

Optimal solutions employing an algebraic Variational Multiscale approach Part I: Steady Linear Problems

A relaxation approach to the coupling of a two-phase fluid with a linear-elastic solid

A divergence-free projection method for quasiperiodic photonic crystals in three dimensions

On a shrink-and-expand technique for block eigensolvers

Uniform Approximation of Eigenproblems of a Large-Scale Parameter-Dependent Hermitian Matrix

Asymptotic Preserving Linearly Implicit Additive IMEX-RK Finite Volume Schemes for Low Mach Number Isentropic Euler Equations

A Canonical Gauge for Computing of Eigenpairs of the Magnetic Schrödinger Operator

Strong convergence of some Magnus-type schemes for the finite element discretization of non-autonomous parabolic SPDEs driven by additive fractional Brownian motion and Poisson random measure

Quantitative approximation of stochastic kinetic equations: from discrete to continuum

A robust fourth-order finite-difference discretization for the strongly anisotropic transport equation in magnetized plasmas

The Weak Form Is Stronger Than You Think

nekCRF: A next generation high-order reactive low Mach flow solver for direct numerical simulations

A construction of canonical nonconforming finite element spaces for elliptic equations of any order in any dimension

Randomized low-rank Runge-Kutta methods

Block structured matrix-sequences and their spectral and singular value canonical distributions: a general theory

Two-level Restricted Additive Schwarz preconditioner based on Multiscale Spectral Generalized FEM for Heterogeneous Helmholtz Problems

A Second Moment Method for k-Eigenvalue Acceleration with Continuous Diffusion and Discontinuous Transport Discretizations

Bi-level regularization via iterative mesh refinement for aeroacoustics

Typicality, entropy and the generalization of statistical mechanics

Coordinate complexification for the Helmholtz equation with Dirichlet boundary conditions in a perturbed half-space

A Reynolds-semi-robust and pressure robust Hybrid High-Order method for the time dependent incompressible Navier--Stokes equations on general meshes

A novel second order scheme with one step for forward backward stochastic differential equations

Anisotropic Error Analysis of Weak Galerkin finite element method for Singularly Perturbed Biharmonic Problems

Finite element approximation of stationary Fokker--Planck--Kolmogorov equations with application to periodic numerical homogenization

Homogenisation for Maxwell and Friends

Approximation of the Hilbert Transform on the unit circle

Entropy Contractions in Markov Chains: Half-Step, Full-Step and Continuous-Time