Browsing by Subject "Brownian particles"
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Item Open Access Active particles in complex and crowded environments(American Physical Society, 2016-11) Bechinger, C.; Di Leonardo, R.; Löwen, H.; Reichhardt, C.; Volpe, G.Differently from passive Brownian particles, active particles, also known as self-propelled Brownian particles or microswimmers and nanoswimmers, are capable of taking up energy from their environment and converting it into directed motion. Because of this constant flow of energy, their behavior can be explained and understood only within the framework of nonequilibrium physics. In the biological realm, many cells perform directed motion, for example, as a way to browse for nutrients or to avoid toxins. Inspired by these motile microorganisms, researchers have been developing artificial particles that feature similar swimming behaviors based on different mechanisms. These man-made micromachines and nanomachines hold a great potential as autonomous agents for health care, sustainability, and security applications. With a focus on the basic physical features of the interactions of self-propelled Brownian particles with a crowded and complex environment, this comprehensive review will provide a guided tour through its basic principles, the development of artificial self-propelling microparticles and nanoparticles, and their application to the study of nonequilibrium phenomena, as well as the open challenges that the field is currently facing.Item Open Access Brownian gyrator: an experimental realization(OSA, 2017) Soni, Jalpa; Argun, A.; Dabelow, L.; Bo, S.; Eichhorn, R.; Pesce, G.; Volpe, GiovanniWe present an experimental realization of a minimal heat engine in the form of a single Brownian particle, performing gyrating motion by systematic torque generation due to dissipation from two different heat baths in a simple optical tweezer set-up.Item Open Access Controlling active brownian particles in complex settings(OSA, 2017) Velu, Sabareesh K. P.; Pinçe, Erçağ; Callegari, Agnese; Elahi, Parviz; Gigan, S.; Volpe, Giovanni; Volpe, G.We show active Brownian particles (passive Brownian particles in a bacterial bath) switches between two long-term behaviors, i.e. gathering and dispersal of individuals, in response to the statistical properties of the underlying optical potential.Item Open Access Long-term influence of fluid inertia on the diffusion of a Brownian particle(American Physical Society, 2014) Pesce, G.; Volpe, G.; Volpe, G.; Sasso, A.We experimentally measure the effects of fluid inertia on the diffusion of a Brownian particle at very long time scales. In previous experiments, the use of standard optical tweezers introduced a cutoff in the free diffusion of the particle, which limited the measurement of these effects to times comparable with the relaxation time of the fluid inertia, i.e., a few milliseconds. Here, by using blinking optical tweezers, we detect these inertial effects on time scales several orders longer up to a few seconds. The measured mean square displacement of a freely diffusing Brownian particle in a liquid shows a deviation from the Einstein-Smoluchowsky theory that diverges with time. These results are consistent with a generalized theory that takes into account not only the particle inertia but also the inertia of the surrounding fluid. © 2014 American Physical Society.Item Open Access Optical manipulation with random light fields: from fundamental physics to applications(OSA, 2015) Volpe, G.; Gigan, S.; Volpe, GiovanniSpeckles are random light fields that share some universal statistical properties. Because of this, they can be used to perform deterministic optical manipulation tasks on a Brownian particle as well as control its diffusion properties.