Particle dynamics in a virtual harmonic potential

Momcilo Gavrilov, Yonggun Jun, John Bechhoefer

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

14 Scopus citations


Feedback traps can create arbitrary virtual potentials for exploring the dynamics of small Brownian particles. In a feedback trap, the particle position is measured periodically and, after each measurement, one applies the force that would be produced by the gradient of the \virtual potential, at the particle location. Virtual potentials differ from real ones in that the feedback loop introduces dynamical effects not present in ordinary potentials. These dynamical effects are caused by small time scales associated with the feedback, including the delay between the measurement of a particle's position and the feedback response, the feedback response that is applied for a finite update time, and the finite camera exposure from integrating motion. Here, we characterize the relevant experimental parameters and compare to theory the observed power spectra and variance for a particle in a virtual harmonic potential. We show that deviations from the dynamics expected of a continuous potential are measured by the ratio of these small time scales to the relaxation time scale of the virtual potential.

Original languageEnglish
Title of host publicationOptical Trapping and Optical Micromanipulation X
StatePublished - 2013
EventOptical Trapping and Optical Micromanipulation X - San Diego, CA, United States
Duration: 25 Aug 201329 Aug 2013

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceOptical Trapping and Optical Micromanipulation X
Country/TerritoryUnited States
CitySan Diego, CA


  • ABEL trap
  • feedback trap
  • Landauer's principle
  • stochastic thermodynamics
  • virtual potential


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