{"title":"An active fractional Ornstein–Uhlenbeck particle: diffusion and dissipation","authors":"Norodin A. Rangaig","doi":"10.1088/1742-5468/ad5714","DOIUrl":"https://doi.org/10.1088/1742-5468/ad5714","url":null,"abstract":"\u0000 In this work, we consider a particle subjected to active fluctuations due to the presence of an active bath. The active fluctuation driving the particle is modeled as an Ornstein–Uhlenbeck process with memory, due to the recent experimental result in that a bacterial bath under a chemotactic mechanism exhibits a large distribution of persistence time, which may result in long-range persistence of a probe particle that cannot be captured by the conventional Ornstein–Uhlenbeck model for active noise. As a paradigmatic model, we consider introducing a fractional Ornstein–Uhlenbeck process with a power-law kernel, which includes a fractional order variable \u0000 \u0000 \u0000 \u0000 0\u0000 <\u0000 α\u0000 ⩽\u0000 1\u0000 \u0000 \u0000 , to model an active noise acting on a particle. We present the relevant properties of the active noise and its implications for the diffusion of free and harmonically confined single particles. This is also supported by the derived active Smoluchowski description. More importantly, we find that the effect of α can either reduce or increase the effective temperature at long time, depending on the competition between the harmonic timescale and persistence time. Lastly, the effects of presented active noise on the spectral density of the energy dissipation rate and the dissipation energy from both the thermal and active bath are explored.","PeriodicalId":506020,"journal":{"name":"Journal of Statistical Mechanics: Theory and Experiment","volume":"50 44","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141644737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dipankar Roy, Abhishek Dhar, Konstantin Khanin, M. Kulkarni, Herbert Spohn
{"title":"Universality in coupled stochastic Burgers systems with degenerate flux Jacobian","authors":"Dipankar Roy, Abhishek Dhar, Konstantin Khanin, M. Kulkarni, Herbert Spohn","doi":"10.1088/1742-5468/ad3196","DOIUrl":"https://doi.org/10.1088/1742-5468/ad3196","url":null,"abstract":"\u0000 In our contribution we study stochastic models in one space dimension with two conservation laws. One model is the coupled continuum stochastic Burgers equation, for which each current is a sum of quadratic nonlinearities, linear diffusion, and spacetime white noise. The second model is a two-lane stochastic lattice gas. As distinct from previous studies, the two conserved densities are tuned such that the flux Jacobian, a \u0000 \u0000 \u0000 \u0000 2\u0000 ×\u0000 2\u0000 \u0000 \u0000 \u0000 matrix, has coinciding eigenvalues. In the steady state, spacetime correlations of the conserved fields and the time-integrated currents at the origin are investigated. For a particular choice of couplings, the dynamical exponent 3/2 is confirmed. Furthermore, at these couplings, the continuum stochastic Burgers equation and lattice gas are demonstrated to be in the same universality class.","PeriodicalId":506020,"journal":{"name":"Journal of Statistical Mechanics: Theory and Experiment","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140509676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}