Measuring kinetic energy changes in the mesoscale with low acquisition rates

Journal Article · Mon Jun 09 00:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4882419· OSTI ID:22300039

Roldán, É. ^[1]; Martínez, I. A.; Dinis, L. ^[2]

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1. ICFO–Institut de Ciències Fotòniques, Mediterranean Technology Park, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona) (Spain)
2. GISC–Grupo Interdisciplinar de Sistemas Complejos, Madrid (Spain)

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.

• OSTI ID: 22300039
• Journal Information: Applied Physics Letters, Vol. 104, Issue 23; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

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