98%
921
2 minutes
20
In this study, we construct surrogate stochastic processes that are challenging to distinguish from ordinary Brownian motion using a method based on the Schauder representation. Specifically, by assuming non-Gaussian (beta and uniform) distributions for the Schauder coefficients, we generate sample paths that preserve key properties of Brownian motion-such as quadratic variation, covariance structure, pointwise Hölder regularity, uncorrelated increments, as well as Gaussian marginal distributions. However, a deeper analysis relying on entropy-based measures and sliding-window spectral variance reveals that only the Gaussian-based construction preserves the expected randomness and the consistent spectral behavior of Brownian motion over time. In contrast, non-Gaussian variants exhibit subtle deviations from true Brownian motion.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1063/5.0287678 | DOI Listing |
NPJ Microgravity
September 2025
Department of Mechanical Engineering, UC Santa Barbara, Santa Barbara, CA, USA.
Microgravity experiments on board the International Space Station, combined with particle-resolved direct numerical simulations, were conducted to investigate the long-term flocculation behavior of clay suspensions in saline water in the absence of gravity. After an initial homogenization of the suspensions, different clay compositions were continuously monitored for 99 days, allowing a detailed analysis of aggregate growth through image processing. The results indicate that the onboard oscillations (g-jitter) may have accelerated the aggregation process.
View Article and Find Full Text PDFJ Chem Phys
September 2025
School of Materials, Sun Yat-Sen University, Shenzhen, Guangdong 518107, China.
We introduce an extended formulation of the non-Markovian stochastic Schrödinger equation with complex frequency modes (extended cNMSSE), designed for simulating open quantum system dynamics under arbitrary spectral densities. This extension employs non-exponential basis sets to expand the bath correlation functions, overcoming the reliance of the original cNMSSE on exponential decompositions of the spectral density. Consequently, the extended cNMSSE is applicable to environments beyond those characterized by Debye-type spectral densities.
View Article and Find Full Text PDFJ Chem Phys
September 2025
Department of Chemistry, University of Rochester, Rochester, New York 14627, USA.
We introduce an efficient method, TTN-HEOM, for exactly calculating the open quantum dynamics for driven quantum systems interacting with highly structured bosonic baths by combining the tree tensor network (TTN) decomposition scheme with the bexcitonic generalization of the numerically exact hierarchical equations of motion (HEOM). The method yields a series of quantum master equations for all core tensors in the TTN that efficiently and accurately capture the open quantum dynamics for non-Markovian environments to all orders in the system-bath interaction. These master equations are constructed based on the time-dependent Dirac-Frenkel variational principle, which isolates the optimal dynamics for the core tensors given the TTN ansatz.
View Article and Find Full Text PDFBiophys J
September 2025
Department of Chromosome Science, National Institute of Genetics, Yata 1111, Mishima, 411-8540, Japan; Genetics Program, Sokendai, Yata 1111, Mishima, 411-8540, Japan.
The viscosity of the plasma membrane in living cells is a crucial biophysical parameter that regulates cellular functions. We categorize the plasma membrane viscosity into short-range and long-range viscosities based on the spatial scale of the cellular processes they influence. Short-range viscosity originates from the Brownian motion of membrane molecules, i.
View Article and Find Full Text PDFAnn Plast Surg
September 2025
From the Department of Plastic Surgery, Vanderbilt University Medical Center, Nashville, TN.
Diffusion tensor imaging (DTI) has revolutionized neuroimaging by enabling a noninvasive visualization of tissue microstructure through the analysis of the apparent diffusion of water molecules. Originating from the foundational principles of Brownian motion and Fick's law, DTI evolved from early diffusion magnetic resonance imaging into an advanced diagnostic tool for in vivo characterization of axonal pathways. This review traces the historical development of DTI and evaluates its expanding clinical applications, particularly in assessing peripheral nerve pathologies.
View Article and Find Full Text PDF