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Solving large systems of equations is a challenge for modeling natural phenomena, such as simulating subsurface flow. To avoid systems that are intractable on current computers, it is often necessary to neglect information at small scales,…

Simulations of condensed matter systems often focus on the dynamics of a few distinguished components but require integrating the dynamics of the full system. A prime example is a molecular dynamics simulation of a (macro)molecule in…

Computational Physics · Physics 2024-03-12 Mauricio J. del Razo , Daan Crommelin , Peter G. Bolhuis

Our main aim in this paper is to promote the coframe variational method as a unified approach to derive field equations for any given gravitational action containing the algebraic functions of the scalars constructed from the Riemann…

General Relativity and Quantum Cosmology · Physics 2015-05-20 Ahmet Baykal , Özgur Delice

Fluctuations in small biological systems can be crucial for their function. Large-deviation theory characterizes such rare events from the perspective of stochastic processes. In most cases it is very difficult to directly determine the…

Statistical Mechanics · Physics 2013-12-03 Artur Wachtel

We propose a sampling algorithm relying on a collective variable (CV) of mid-size dimension modelled by a normalizing flow and using non-equilibrium dynamics to propose full configurational moves from the proposition of a refreshed value of…

Statistical Mechanics · Physics 2024-07-29 Samuel Tamagnone , Alessandro Laio , Marylou Gabrié

A variational approach to finite connectivity spin-glass-like models is developed and applied to describe the structure of optimal solutions in random satisfiability problems. Our variational scheme accurately reproduces the known replica…

Disordered Systems and Neural Networks · Physics 2009-10-31 Giulio Biroli , Remi Monasson , Martin Weigt

Semi-analytical methods, based on Eulerian perturbation theory, are a promising tool to follow the time evolution of cosmological perturbations at small redshifts and at mildly nonlinear scales. All these schemes are based on two…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Massimo Pietroni , Gianpiero Mangano , Ninetta Saviano , Matteo Viel

We present a conformally invariant generalized form of the free particle action by connecting the wave and particle aspects through gravity. Conformal invariance breaking is introduced by choosing a particular configurat$ of dynamical…

High Energy Physics - Theory · Physics 2009-10-31 Hossein Motavali , Hadi Salehi , Mehdi Golshani

Several recent works have explored stochastic gradient methods for variational inference that exploit the geometry of the variational-parameter space. However, the theoretical properties of these methods are not well-understood and these…

Machine Learning · Statistics 2016-08-15 Mohammad Emtiyaz Khan , Reza Babanezhad , Wu Lin , Mark Schmidt , Masashi Sugiyama

We present a coarse-graining strategy for reducing the number of particle species in mixtures to achieve a simpler system with higher diffusion while preserving the total particle number and characteristic dynamic features. As a system of…

Soft Condensed Matter · Physics 2020-09-16 Thomas Heinemann , YounJoon Jung

Complex fluids exhibit structure on a wide range of length and time scales, and hierarchical approaches are necessary to investigate all facets of their often unusual properties. The study of idealized coarse-grained models at different…

Soft Condensed Matter · Physics 2008-10-23 Friederike Schmid

A fundamental question in nonequilibrium statistical physics is whether effective equilibrium behavior can emerge at coarse-grained scales in strongly driven systems. Here, we investigate this question in the context of human mobility by…

Physics and Society · Physics 2026-03-24 Lei Dong

Based on a nonsmooth coherence condition, we construct and prove the convergence of a forward-backward splitting method that alternates between steps on a fine and a coarse grid. Our focus is a total variation regularised inverse imaging…

Optimization and Control · Mathematics 2025-05-21 Felipe Guerra , Tuomo Valkonen

This paper is concerned with a singular limit of the Kobayashi-Warren-Carter system, a phase field system modelling the evolutions of structures of grains. Under a suitable scaling, the limit system is formally derived when the interface…

Analysis of PDEs · Mathematics 2023-06-28 Yoshikazu Giga , Ayato Kubo , Hirotoshi Kuroda , Jun Okamoto , Koya Sakakibara , Masaaki Uesaka

In this paper, a statistical physical derivation of thermodynamically consistent fluid mechanical equations is presented for non-isothermal viscous molecular fluids. The coarse-graining process is based on (i) the adiabatic expansion of the…

Statistical Mechanics · Physics 2024-04-18 Gyula I. Tóth

An expression for the stress tensor near an external boundary of a discrete mechanical system is derived explicitly in terms of the constituents' degrees of freedom and interaction forces. Starting point is the exact and general coarse…

Soft Condensed Matter · Physics 2011-08-26 Thomas Weinhart , Anthony R. Thornton , Stefan Luding , Onno Bokhove

Coarse-graining has become an area of tremendous importance within many different research fields. For molecular simulation, coarse-graining bears the promise of finding simplified models such that long-time simulations of large-scale…

Chemical Physics · Physics 2019-09-04 Feliks Nüske , Lorenzo Boninsegna , Cecilia Clementi

Constrained quantum dynamics is used to propose a nonlinear dynamical equation for pure states of a generalized coarse-grained system. The relevant constraint is given either by the generalized purity or by the generalized invariant…

Quantum Physics · Physics 2015-05-19 Nikola Buric

We present a new approach to coarse-graining of variables describing dust flow in GR. It is based on assigning quasi-local shear, twist and expansion to 2-dimensional surfaces with the help of isometric embeddings into the 3-dimensional…

General Relativity and Quantum Cosmology · Physics 2015-05-14 Mikolaj Korzynski

Additive or multiplicative stationary noise recently became an important issue in applied fields such as microscopy or satellite imaging. Relatively few works address the design of dedicated denoising methods compared to the usual white…

Computer Vision and Pattern Recognition · Computer Science 2013-07-18 Jérôme Fehrenbach , Pierre Weiss