2023/08/16 by Omer Granek, Granek, Omer
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #FOS: Physical sciences #Soft Condensed Matter (cond-mat.soft) #Spectroscopy and Quantum Chemical Studies #Statistical Mechanics (cond-mat.stat-mech) #Theoretical and Computational Physics
paper · pdf · doi:10.48550/arxiv.2308.08595
openalex publication_date 2023/08/16 · openalex created_date 2023/08/22 · openalex updated_date 2026/08/01
Measuring transport coefficients at the microscale remains challenging, often relying on indirect methods that require modeling and calibration. This Letter derives universal asymptotic forms for the autocorrelation and relative uncertainty of local probe measurements in dilute diffusive systems. Valid both at and far from equilibrium, these forms directly connect microscopic measurements to the effective diffusivity. Indirect methods such as dynamic light scattering and fluorescence correlation spectroscopy are thereby elevated to asymptotically direct probes. They become capable of measuring the effective diffusivity of active and other microscopically nondiffusive systems. Simulations across several models confirm the broad applicability of these predictions.