Force measurement in the presence of Brownian noise: Equilibrium- distribution method versus drift method

Thomas Brettschneider, Giovanni Volpe, Laurent Helden, Jan Wehr, Clemens Bechinger

Research output: Contribution to journalArticle

48 Scopus citations

Abstract

The study of microsystems and the development of nanotechnologies require alternative techniques to measure piconewton and femtonewton forces at microscopic and nanoscopic scales. Among the challenges is the need to deal with the ineluctable thermal noise, which, in the typical experimental situation of a spatial diffusion gradient, causes a spurious drift. This leads to a correction term when forces are estimated from drift measurements. Here we provide a systematic study of such an effect by comparing the forces acting on various Brownian particles derived from equilibrium-distribution and drift measurements. We discuss the physical origin of the correction term, its dependence on wall distance and particle radius, and its relation to the convention used to solve the respective stochastic integrals. Such a correction term becomes more significant for smaller particles and is predicted to be on the order of several piconewtons for particles the size of a biomolecule.

Original languageEnglish (US)
Article number041113
JournalPhysical Review E - Statistical, Nonlinear, and Soft Matter Physics
Volume83
Issue number4
DOIs
StatePublished - Apr 15 2011

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Statistics and Probability
  • Condensed Matter Physics

Fingerprint Dive into the research topics of 'Force measurement in the presence of Brownian noise: Equilibrium- distribution method versus drift method'. Together they form a unique fingerprint.

  • Cite this