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Title: Measuring kinetic energy changes in the mesoscale with low acquisition rates

We report on the measurement of the average kinetic energy changes in isothermal and non-isothermal quasistatic processes in the mesoscale, realized with a Brownian particle trapped with optical tweezers. Our estimation of the kinetic energy change allows to access to the full energetic description of the Brownian particle. Kinetic energy estimates are obtained from measurements of the mean square velocity of the trapped bead sampled at frequencies several orders of magnitude smaller than the momentum relaxation frequency. The velocity is tuned applying a noisy electric field that modulates the amplitude of the fluctuations of the position and velocity of the Brownian particle, whose motion is equivalent to that of a particle in a higher temperature reservoir. Additionally, we show that the dependence of the variance of the time-averaged velocity on the sampling frequency can be used to quantify properties of the electrophoretic mobility of a charged colloid. Our method could be applied to detect temperature gradients in inhomogeneous media and to characterize the complete thermodynamics of biological motors and of artificial micro and nanoscopic heat engines.
Authors:
 [1] ;  [2] ; ;  [1] ;  [3] ;  [2]
  1. ICFO–Institut de Ciències Fotòniques, Mediterranean Technology Park, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona) (Spain)
  2. (Spain)
  3. GISC–Grupo Interdisciplinar de Sistemas Complejos, Madrid (Spain)
Publication Date:
OSTI Identifier:
22300039
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 23; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 77 NANOSCIENCE AND NANOTECHNOLOGY; AMPLITUDES; BROWNIAN MOVEMENT; COLLOIDS; ELECTRIC FIELDS; ELECTROPHORESIS; FLUCTUATIONS; HEAT ENGINES; KINETIC ENERGY; MICROSTRUCTURE; MOBILITY; MOTORS; NANOSTRUCTURES; PARTICLES; RELAXATION; TEMPERATURE GRADIENTS; THERMODYNAMICS; TRAPPING