Article
Multidisciplinary Sciences
Jakub Slezak, Stanislav Burov
Summary: This study establishes a link between diffusion in compartmentalized environment and non-Gaussian diffusion, using a microscopic model with randomly placed barriers. The observed exponential decay of positional probability density is a general feature of transient regime in compartmentalized media.
SCIENTIFIC REPORTS
(2021)
Article
Mathematics
Shiping Cao, Qingsong Gu, Hua Qiu
Summary: In this study, we extend the construction of Dirichlet forms to the setting of 1 < p < infinity by studying p-energies on post-critically finite self-similar sets as limits of discrete p-energies on approximation graphs. By enlarging the choices of discrete p-energies and using the energy averaging method, we prove the existence of symmetric p-energies on affine nested fractals and extend Sabot's criterion for the existence and non-existence of Dirichlet forms on p.c.f. self-similar sets to the 1 < p < infinity setting.
ADVANCES IN MATHEMATICS
(2022)
Article
Materials Science, Multidisciplinary
Werner Dobrautz, Vamshi M. Katukuri, Nikolay A. Bogdanov, Daniel Kats, Giovanni Li Manni, Ali Alavi
Summary: This study uses a novel approach that combines unitary and symmetric groups to investigate the spin-1/2 Heisenberg model and related Fermionic systems. The results show that combining these groups leads to a more compact representation of the ground-state wave function. Additionally, the compression of the wave function allows for the study of larger lattices.
Article
Chemistry, Physical
Aditi Khot, Brett M. Savoie
Summary: Coarse-grained molecular dynamics (CGMD) simulations address critical lengthscales and timescales in chemical and material applications. The development of black-box CGMD methodologies similar to density functional theory for electronic structure is still lacking. Machine learning (ML)-based CGMD potentials show promise in simplifying model development, but they have yet to outperform physics-based CGMD methods. In this study, λ-learning models are explored to combine the advantages of both approaches. The λ-models outperform ML-only CGMD models and provide essentially free gains in reproducing atomistic properties. However, neither the λ-learning models nor the ML-only models significantly outperform elementary pairwise models in reproducing atomistic properties due to the large irreducible force errors associated with coarse-graining.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Adam G. Kline, Stephanie E. Palmer
Summary: This manuscript explores the formal equivalence between information bottleneck (IB) and renormalization group (RG). By defining a class of non-deterministic coarsening maps, a subclass of soft-cutoff non-perturbative RG techniques is formally mapped onto IB, and vice versa. The results suggest that IB can be used to impose a notion of 'large scale' structure on an RG procedure.
NEW JOURNAL OF PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Cheng-Hui Xia, Julia Kundin, Ingo Steinbach, Sergiy Divinski
Summary: The effect of non-equilibrium vacancy on Kirkendall porosity formation was studied using a developed model of multi-component diffusion with vacancies (MDV). The results showed that the vacancy distribution strongly influences the porosity, while the diffusion profiles of substitutional components slightly depend on the intensity of source/sink.
Article
Biochemistry & Molecular Biology
Francesco Rusciano, Raffaele Pastore, Francesco Greco
Summary: Recent works reveal that glass-forming liquids exhibit Fickian non-Gaussian diffusion, with non-Gaussian displacement distributions persisting even after attaining linearity in mean square displacement. These non-Gaussian deviations exhibit exponential tails with a growing decay length proportional to a power-law in time. The study examines data from different glass-forming systems and identifies a scaling law for the decay length, which holds for all systems regardless of dimensionality. Additionally, a universal characteristic time for the disappearance of exponential tails and the recovery of Gaussianity is found across different temperatures/concentrations within each system, related to the onset of Fickianity through a power-law.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Environmental Sciences
Weichen Sun, Xiaochen Wang, Bing Han, Dadi Meng, Wei Wan
Summary: This paper proposes a scattering model for the observation geometry of Global Navigation Satellite System Reflectometry (GNSS-R) based on the small-slope approximation model of non-Gaussian sea surface. The scattering characteristics under different wind speeds and directions on the ocean surface are analyzed using the method of polarization synthesis, and the accuracy of the scattering model is improved by comparing with CYGNSS data. The study also discusses the scattering influence and the relative relationship between different polarizations of the scattering angle under the non-specular geometry.
Article
Physics, Multidisciplinary
Elisabeth Lemaitre, Igor M. Sokolov, Ralf Metzler, Aleksei Chechkin
Summary: We study the effects of randomly distributed diffusivities and speeds in two models for active particle dynamics. We find that non-Gaussian displacement distributions, including Cauchy-type and exponential shapes, emerge in these models in the long time limit. The resulting shapes of the displacement distributions with distributed diffusivities for the active models are in striking contrast to passive diffusion models. Additionally, we demonstrate that the case with active-noise agrees well with measured data for the displacement distribution of social amoeba.
NEW JOURNAL OF PHYSICS
(2023)
Article
Mathematics, Applied
A. Diaz-Ruelas, F. Baldovin, A. Robledo
Summary: The study investigates the evolution of probability density of ensembles of iterates of the logistic map towards and at attractors of representative dynamical regimes. Mirror families of superstable and chaotic-band attractors are considered, along with their common aperiodic accumulation point. The analysis reveals a scaling of densities along attractor families conforming to a renormalization-group structure, with entropies attaining extrema at the fixed points of the RG flows. Additionally, the entropy as a function of the map control parameter exhibits features of a thermal system undergoing a second-order phase transition.
Article
Physics, Multidisciplinary
Dmytro Shapoval, Viktoria Blavatska, Maxym Dudka
Summary: This study analyzes a two-species reaction-diffusion system that includes trapping reactions and species diffusion.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Article
Chemistry, Physical
Brandon C. Bukowski, Florencia A. Son, Yongwei Chen, Lee Robison, Timur Islamoglu, Randall Q. Snurr, Omar K. Farha
Summary: Identifying mass transfer limitations is crucial for the practical application of nanoporous materials. In this study, we investigated the adsorption behavior of nine Zr-MOFs and found that the uptake rates were limited by mass transfer at the crystal surfaces. The severity and dependence of these surface resistances varied for each MOF.
CHEMISTRY OF MATERIALS
(2022)
Article
Energy & Fuels
Toby R. F. Phillips, Claire E. Heaney, Brendan S. Tollit, Paul N. Smith, Christopher C. Pain
Summary: This paper proposes a method that combines reduced-order modelling with domain decomposition to solve the challenging computational problem of solving the neutron transport equations. Through testing on a one-dimensional slab reactor, it is found that the domain decomposition reduced-order model methods have the potential to significantly reduce offline computational costs while performing comparably to global reduced-order model methods when the total number of variables is the same.
Article
Physics, Multidisciplinary
Masami Matsumoto, Gota Tanaka, Asato Tsuchiya
Summary: The relationship between the renormalization group and the diffusion equation was studied, finding that correlation functions of diffused fields are in agreement with those of bare fields. This suggests a correspondence between the two equations.
PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS
(2021)
Article
Multidisciplinary Sciences
Nikita A. Dmitryuk, Lucia A. Mistryukova, Nikita P. Kryuchkov, Sergey A. Khrapak, Stanislav O. Yurchenko
Summary: The diffusion mobility of particles in simple fluids increases linearly on the liquid branch of the liquid-gas binodal. High-frequency spectra show solid-like oscillating behavior above the triple point. These findings have significant implications in the field of physics and chemistry.
SCIENTIFIC REPORTS
(2023)
Article
Mechanics
David S. Dean, Paul Gersberg, Peter C. W. Holdsworth
JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT
(2020)
Article
Chemistry, Physical
M. Mangeat, T. Guerin, D. S. Dean
JOURNAL OF CHEMICAL PHYSICS
(2020)
Article
Physics, Multidisciplinary
David S. Dean, Bing Miao, Rudolf Podgornik
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2020)
Article
Physics, Multidisciplinary
David S. Dean, Pierre Le Doussal, Satya N. Majumdar, Gregory Schehr, Naftali R. Smith
Summary: The study presents a general method for computing the quantum correlations of N non interacting spinless fermions in their ground state, expressed in terms of a two-point function called the kernel. The method allows for a simple derivation of the local density approximation and the sine kernel in smooth potentials in one dimension, and recovers the density and kernel of the Airy gas at the edge of the trap. Additionally, the method can analyze quantum correlations in the ground state when the potential has a singular part with fast spatial variation.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2021)
Article
Physics, Multidisciplinary
David S. Dean, Pierre Le Doussal, Satya N. Majumdar, Gregory Schehr
Summary: The study focuses on the properties of spin-less non-interacting fermions trapped in a one-dimensional confining potential with one or more impurities modeled by delta function potentials. The method based on the single particle Green's function is employed to calculate the effects of impurities on the Fermi gas density and the effective potential. Results show interesting transitions and modifications in the density and potential when impurities are placed at different locations, such as near the edge of the trap or in the bulk.
Article
Mechanics
A. Alexandre, T. Guerin, D. S. Dean
Summary: The study focuses on Taylor dispersion of tracer particles in microfluidic channels with strong confinement, highlighting the influence of channel walls on diffusivity and interactions with the tracer particles. A simple and general formula is provided for calculating the effective diffusion constant along the channel and the first non-trivial finite time correction, applicable to various flow conditions, interaction potentials, and diffusion tensors. The formulas are particularly useful for numerical implementation and comparison with experiments.
Article
Mechanics
Matthieu Mangeat, Thomas Guerin, David S. Dean
Summary: This paper presents an exact solution for the steady state statistics of overdamped Brownian particles in an optical trap subjected to a non-conservative scattering force. The results include certain marginals of the full three-dimensional steady state probability distribution and toroidal probability currents. The analytical results are confirmed by numerical solutions of the steady state Fokker-Planck equation.
JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT
(2021)
Article
Physics, Multidisciplinary
A. Alexandre, M. Mangeat, T. Guerin, D. S. Dean
Summary: Using a general adsorption desorption model with surface diffusion, this study analytically shows that making surfaces or obstacles attractive can accelerate dispersion.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Alexandre Vilquin, Vincent Bertin, Elie Raphael, David S. Dean, Thomas Salez, Joshua D. McGraw
Summary: This study focuses on the spatial distribution and dispersion of charged nanoparticles in near-surface shear flows under the influence of electrostatic repulsion and absorption. By varying electrolyte concentrations, the electrostatic repulsion between particles and the charged surface can be adjusted. The particles leaving the field of vision are excluded from further analysis, making the experimental ensemble equivalent to Taylor dispersion with absorption. These two factors significantly modify the particle distribution and lead to a tenfold reduction in the spreading dynamics compared to the noninteracting case.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Arthur Alexandre, Maxime Lavaud, Nicolas Fares, Elodie Millan, Yann Louyer, Thomas Salez, Yacine Amarouchene, Thomas Guerin, David S. Dean
Summary: This study investigates the diffusion of particles in single-wall and double-wall planar channel geometries with a dependence of local diffusivities on the distance to the boundaries. The displacement parallel to the walls is Brownian but non-Gaussian, exhibiting a nonzero fourth cumulant. The fourth cumulant and the tails of the displacement distribution are calculated, incorporating diffusivity tensors and potentials generated by the walls or external factors like gravity. Experimental and numerical studies confirm the accuracy of the predicted fourth cumulants, while surprising findings indicate that the tails of the displacement distribution are Gaussian rather than exponential. Overall, this research provides important insights and constraints for understanding force maps and local transport properties near surfaces.
PHYSICAL REVIEW LETTERS
(2023)
Article
Mechanics
David S. Dean, Satya N. Majumdar, Gregory Schehr
Summary: This paper investigates the problem of leakage or effusion of an ensemble of independent stochastic processes from a region where they are initially randomly distributed. The case of Brownian motion, initially confined to the left half line with uniform density and leaking into the positive half line, has been extensively studied. The authors derive new results for the average number and variance of the number of leaked particles for arbitrary Gaussian processes initially confined to the negative half line, and also derive its joint two-time probability distribution, both for the annealed and the quenched initial conditions. They show that the strong memory effects in the variance of the particle number on the positive real axis for Brownian particles persist for arbitrary Gaussian processes and also at the level of two-time correlation functions.
JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT
(2023)
Article
Optics
Benjamin De Bruyne, David S. Dean, Pierre Le Doussal, Satya N. Majumdar, Gregory Schehr
Summary: This study investigates the structure of the Wigner function in the quantum region, particularly focusing on the edge of the Fermi surface, identifying three distinct edge regions and their scaling functions. Additionally, a striking algebraic tail is found for very large momenta, well beyond the Fermi momentum, reminiscent of a similar phenomenon in interacting quantum systems. These results are then extended to higher dimensions, revealing a universal scaling function near the edge of the box, independent of the dimension.
Article
Physics, Fluids & Plasmas
David S. Dean, Satya N. Majumdar, Hendrik Schawe
Summary: A class of stochastic processes is studied in which the behavior changes with different values of n, with a localization transition occurring at n = 1/2. The position distribution exhibits different characteristics for different n values, with a transition to a stationary form for n < 1/2.
Article
Optics
Naftali R. Smith, David S. Dean, Pierre Le Doussal, Satya N. Majumdar, Gregory Schehr
Article
Physics, Fluids & Plasmas
Matthieu Mangeat, Yacine Amarouchene, Yann Louyer, Thomas Guerin, David S. Dean
