We study the motion of a one-dimensional run-and-tumble particle with three discrete internal states in the presence of a harmonic trap of stiffness The three internal states, corresponding to ...positive, negative and zero velocities respectively, evolve following a jump process with rate . We compute the stationary position distribution exactly for arbitrary values of and which turns out to have a finite support on the real line. We show that the distribution undergoes a shape-transition as is changed. For the distribution has a double-concave shape and shows algebraic divergences with an exponent both at the origin and at the boundaries. For the position distribution becomes convex, vanishing at the boundaries and with a single, finite, peak at the origin. We also show that for the special case the distribution shows a logarithmic divergence near the origin while saturating to a constant value at the boundaries.
For a large class of nonequilibrium systems, thermodynamic notions like work, heat, and, in particular, entropy production can be identified on the level of fluctuating dynamical trajectories. Within ...stochastic thermodynamics various fluctuation theorems relating these quantities have been proven. Their application to experimental systems requires that all relevant mesostates are accessible. Recent advances address the typical situation that only partial, or coarse-grained, information about a system is available. Thermodynamic inference as a general strategy uses consistency constraints derived from stochastic thermodynamics to infer otherwise hidden properties of nonequilibrium systems. An important class in this respect are active particles, for which we resolve the conflicting strategies that have been proposed to identify entropy production. As a paradigm for thermodynamic inference, the thermodynamic uncertainty relation provides a lower bound on the entropy production through measurements of the dispersion of any current in the system. Likewise, it quantifies the cost of precision for biomolecular processes. Generalizations and ramifications allow the inference of, inter alia, model-free upper bounds on the efficiency of molecular motors and of the minimal number of intermediate states in enzymatic networks.
Collective Motions
In article number 2304759, Yuebing Zheng and co‐workers introduce an experimental platform for customizing motions of active particles, enabling the mimicry of natural collective ...movements. This platform generates spontaneous, diverse motion patterns in particles through designed interaction rules, dynamically influenced by inherent system perturbations.
Particles adsorbed to fluid interfaces are ubiquitous in industry, nature or life. The wide range of properties arising from the assembly of particles at fluid interface has stimulated an intense ...research activity on shed light to the most fundamental physico-chemical aspects of these systems. These include the mechanisms driving the equilibration of the interfacial layers, trapping energy, specific inter-particle interactions and the response of the particle-laden interface to mechanical perturbations and flows. The understanding of the physico-chemistry of particle-laden interfaces becomes essential for taking advantage of the particle capacity to stabilize interfaces for the preparation of different dispersed systems (emulsions, foams or colloidosomes) and the fabrication of new reconfigurable interface-dominated devices. This review presents a detailed overview of the physico-chemical aspects that determine the behavior of particles trapped at fluid interfaces. This has been combined with some examples of real and potential applications of these systems in technological and industrial fields. It is expected that this information can provide a general perspective of the topic that can be exploited for researchers and technologist non-specialized in the study of particle-laden interfaces, or for experienced researcher seeking new questions to solve.
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•Particle-laden fluid interfaces are ubiquitous in science and technology.•Trapping of particles to fluid interfaces depends on particle chemistry, geometry and size.•Trapping energy and inter-particle interactions control assembly and properties of particle-laden interfaces•Modulating the properties of particle-laden interface allows their technological exploitation.
This review presents the recent progress in the development of active particles driven by alternating-current (AC) electrokinetic effects. These particles propel by asymmetrically dissipating the ...external energy provided by the fields. An AC field can trigger several electrohydrodynamic mechanisms depending on the field frequency and amplitude, which can also control particle–particle interactions and collective behavior. Recently there has been a strong focus on powering and controlling the motion of self-propelling particles with engineered shape, size, and composition. We introduce a tiered classification of AC field-driven active particles and discuss the fundamental electrohydrodynamic effects acting in individual and multi-particle systems. Finally, we address the limitations and challenges in the current state of AC-field driven engineered particles.
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The modeling of living systems composed of many interacting entities is treated in this paper with the aim of describing their collective behaviors. The mathematical approach is developed within the ...general framework of the kinetic theory of active particles. The presentation is in three parts. First, we derive the mathematical tools, subsequently, we show how the method can be applied to a number of case studies related to well defined living systems, and finally, we look ahead to research perspectives.
Many kinds of active particles, such as bacteria or active colloids, move in a thermostatted fluid by means of self-propulsion. Energy injected by such a non-equilibrium force is eventually ...dissipated as heat in the thermostat. Since thermal fluctuations are much faster and weaker than self-propulsion forces, they are often neglected, blurring the identification of dissipated heat in theoretical models. For the same reason, some freedom—or arbitrariness—appears when defining entropy production. Recently three different recipes to define heat and entropy production have been proposed for the same model where the role of self-propulsion is played by a Gaussian coloured noise. Here we compare and discuss the relation between such proposals and their physical meaning. One of these proposals takes into account the heat exchanged with a non-equilibrium active bath: such an “active heat” satisfies the original Clausius relation and can be experimentally verified.
Micromotor-mediated label-free cargo manipulation Wu, Yue; Boymelgreen, Alicia; Yossifon, Gilad
Current opinion in colloid & interface science,
October 2022, 2022-10-00, Letnik:
61
Journal Article
Recenzirano
Efficient and flexible cargo manipulation at the micro/nanoscale is key to the realization of an array of applications ranging from drug delivery, directed self-assembly, and environmental ...remediation to self-repair. In this review, we highlight recent advances in the label-free manipulation of cargo by microscale carriers, commonly referred to as “micromotors” Label-free manipulation eliminates the need for tagging of cargo, enabling on-demand dynamic selectivity. Primary mechanisms include electrical, optical, hydrodynamical, and mechanical forcing. For the carrier, both self-propelling active particles moving in a uniform field and smart passive structures moving in a field gradient are considered with the caveat that cargo manipulation is “micromotor-mediated,” i.e., cargo is not manipulated directly by the applied fields but only through its interaction with the carrier. We compare the manipulation techniques in terms of selectivity, cargo size, material, and suspending medium. We conclude by summarizing the existing challenges and future prospects.
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