Title:	Stationary states of activity-driven harmonic chains
Authors:	Sarkar, Ritwick Santra, Ion Basu, Urna
Keywords:	fluctuation and noise nonequilibrium statistical mechanics harmonic oscillator green's function methods
Issue Date:	17-Jan-2023
Publisher:	American Physical Society
Citation:	Physical Review E, 2023, Vol.107, p014123
Abstract:	We study the stationary state of a chain of harmonic oscillators driven by two active reservoirs at the two ends. These reservoirs exert correlated stochastic forces on the boundary oscillators which eventually leads to a nonequilibrium stationary state of the system. We consider three most well-known dynamics for the active force, namely, the active Ornstein-Uhlenbeck process, run-and-tumble process, and active Brownian process, all of which have exponentially decaying two-point temporal correlations but very different higher-order fluctuations. We show that, irrespective of the specific dynamics of the drive, the stationary velocity fluctuations are Gaussian in nature with a kinetic temperature which remains uniform in the bulk. Moreover, we find the emergence of an “equipartition of energy” in the bulk of the system—the bulk kinetic temperature equals the bulk potential temperature in the thermodynamic limit. We also calculate the stationary distribution of the instantaneous energy current in the bulk which always shows a logarithmic divergence near the origin and asymmetric exponential tails. The signatures of specific active driving become visible in the behavior of the oscillators near the boundary. This is most prominent for the RTP- and ABP-driven chains where the boundary velocity distributions become non-Gaussian and the current distribution has a finite cutoff.
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/8040
ISSN:	2470-0053 (Online) 2470-0045
Alternative Location:	https://arxiv.org/abs/2210.09035 https://doi.org/10.1103/PhysRevE.107.014123 https://ui.adsabs.harvard.edu/abs/2023PhRvE.107a4123S/abstract
Copyright:	2023 American Physical Society
Appears in Collections:	Research Papers (TP)

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