Experimental investigation of active noise on a rotor in an active granular bath

Cheng, Ke; Liu, Peng; Yang, Mingcheng; Hou, Meiying

doi:10.1039/d1sm01798e

Cited by 10 publications

(4 citation statements)

References 43 publications

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“…We now use the expressions derived in Section 3.1 to inspect the stationary moments of the particle. Specializing Equations (37) and (38) for the Gaussian PDF (56) we find that the mean and the variance of the position in this case become…”

Section: Gaussian Kicksmentioning

confidence: 99%

“…Such studies showed that the displacement distribution of the confined particle becomes progressively non-Gaussian with increasing activity of the (bacterial) bath. [15,[33][34][35][36][37][38] The distribution of the system exhibits a concentrated central region with heavier-than-Gaussian tails, thereby enhancing the system dynamics. [36,[39][40][41][42][43][44][45][46][47] Under the influence of coloured noise, two approximations to the stationary probability distribution for Langevin dynamics with colored Ornstein-Uhlenbeck noise in conservative potentials are extensively investigated in literature (Fox [48] and UCNA [49] ).…”

Section: Introductionmentioning

confidence: 99%

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Brownian Particle in a Poisson‐Shot‐Noise Active Bath: Exact Statistics, Effective Temperature, and Inference

Di Bello,

Majumdar,

Marathe

et al. 2024

Annalen der Physik

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The dynamics of an overdamped Brownian particle in a thermal bath that contains a dilute solution of active particles is studied. The particle moves in a harmonic potential and experiences Poisson shot‐noise kicks with specified amplitude distribution due to moving active particles in the bath. From the Fokker–Planck equation for the particle dynamics, the stationary solution for the displacement distribution is derived along with the moments characterizing mean, variance, skewness, and kurtosis, as well as finite‐time first and second moments. An effective temperature is also computed through the fluctuation–dissipation theorem and show that equipartition theorem holds for all zero‐mean kick distributions, including those leading to non‐Gaussian stationary statistics. For the case of Gaussian‐distributed active kicks, a re‐entrant behavior from non‐Gaussian to Gaussian stationary states and a heavy‐tailed leptokurtic distribution across a wide range of parameters are found as seen in recent experimental studies. Further analysis reveals statistical signatures of the irreversible dynamics of the particle displacement in terms of the time asymmetry of cross‐correlation functions. Fruits of the work is the development of an compact inference scheme that may allow experimentalists to extract the rate and moments of underlying shot‐noise solely from the statistics the particle position.

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Section: Gaussian Kicksmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Brownian Particle in a Poisson‐Shot‐Noise Active Bath: Exact Statistics, Effective Temperature, and Inference

Di Bello,

Majumdar,

Marathe

et al. 2024

Annalen der Physik

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“…In the seminal work, Wu and Libchaber found the enhanced diffusion of microspheres emerging in the bacterial bath, with an apparent diffusion coefficient two orders of magnitude larger than that in the pure thermal bath [ 15 ]. Extensive investigations have been conducted to illustrate the diffusion enhancement in the living bath, and a transition from ballistic motion to super diffusion at a short time scale, then back to the normal diffusion in a long time regime [ 17 , 18 , 25 , 26 , 27 , 28 , 29 ]. Additionally, spacial confinement constrains the motion of bacteria with walls, in which, for example, microfluidic channels can preliminarily change the hydrodynamical boundary condition for the swimming bacteria and the interaction among intra-cells [ 30 , 31 , 32 , 33 , 34 , 35 ].…”

Section: Introductionmentioning

confidence: 99%

Activity-Induced Enhancement of Superdiffusive Transport in Bacterial Turbulence

2022

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Superdiffusion processes significantly promote the transport of tiny passive particles within biological fluids. Activity, one of the essential measures for living matter, however, is less examined in terms of how and to what extent it can improve the diffusivity of the moving particles. Here, bacterial suspensions are confined within the microfluidic channel at the state of bacterial turbulence, and are tuned to different activity levels by oxygen consumption in control. Systematic measurements are conducted to determine the superdiffusion exponent, which characterizes the diffusivity strength of tracer particles, depending on the continuously injecting energy converted to motile activity from swimming individuals. Higher activity is quantified to drastically enhance the superdiffusion process of passive tracers in the short-time regime. Moreover, the number density of the swimming bacteria is controlled to contribute to the field activity, and then to strengthen the super-diffusivity of tracers, distinguished by regimes with and without collective motion of interacting bacteria. Finally, the non-slip surfaces of the microfluidic channel lower the superdiffusion of immersed tracers due to the resistance, with the small diffusivity differing from the counterpart in the bulk. The findings here suggest ways of controlled diffusion and transport of substances within the living system with different levels of nutrition and resources and boundary walls, leading to efficient mixing, drug delivery and intracellular communications.

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“…Another illustrative example, is a particle half-metal coated under laser irradiation that undergoes self-thermophoresis due to a local temperature gradient induced by a laser beam [13]. On the other hand, granular materials turn out to be examples of physical realization of active matter [14][15][16], where the shape anisotropy of the single grains under vertical vibration can be produce motility on a horizontal surface [14]. For instance, the single-particle active motion can be generated in a vibrated granular system, where the main features of the Active Brownian Motion model has been proved in [17].…”

Section: Introductionmentioning

confidence: 99%

Magnetized granular particles running and tumbling on $S^{1}$

Ledesma-Motolinia¹,

Carrillo-Estrada²,

Escobar³

et al. 2022

Preprint

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It has been shown that a nonvibrated magnetic granular system, when it is feeded by means an altenating magnetic field, behaves with most of the distinctive physical features of active matter systems. In this work we focus our attention on the simplest granular system composed by a single magnetized spherical particle allocated in a quasi one-dimensional circular channel that receives energy from a magnetic field reservoir and transduces it into a running and tumbling motion. The theoretical analysis based on the run and tumble model on a circle of radius R forecasts the existence of a dynamical phase transition between an erratic motion (disordered phase) when the characteristic persistence length of the run and tumble motion, c < R/2, to a persistent motion (ordered phase) when c > R/2. It is found that the limiting behaviours of these phases correspond to a Brownian motion on the circle and a simple uniform circular motion, respectively. It is qualitatively shown that the lower magnetization of a particle, the larger persistence lenght is. It is so at least within the experimental limit of validity of our experiments. Our results show a very good agreement between theory and experiment.

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Experimental investigation of active noise on a rotor in an active granular bath

Abstract: In an active bath, besides thermal noise, immersed passive objects also persistently experience collisions from active particles, which are often coarse-grained into a colored active noise with an assumed exponential...

Cited by 10 publications

References 43 publications

Brownian Particle in a Poisson‐Shot‐Noise Active Bath: Exact Statistics, Effective Temperature, and Inference

Brownian Particle in a Poisson‐Shot‐Noise Active Bath: Exact Statistics, Effective Temperature, and Inference

Activity-Induced Enhancement of Superdiffusive Transport in Bacterial Turbulence

Magnetized granular particles running and tumbling on $S^{1}$

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