title: Noise associated with nonconservative forces in optical traps.
abstract: It is known that for a particle held in an optical trap the interaction of thermal fluctuations with a nonconservative scattering force can cause a persistent nonequilibrium probability flux in the particle position. We investigate position fluctuations associated with this nonequilibrium flux analytically and through simulation. We introduce a model which reproduces the nonequilibrium effects, and in which the magnitude of additional position fluctuations can be calculated in closed form. The ratio of additional nonconservative fluctuations to direct thermal fluctuations scales inversely with the square root of trap power, and is small for typical experimental parameters. In a simulated biophysical experiment the nonconservative scattering force does not significantly increase the observed fluctuations in the length of a double-stranded DNA tether.
authors: Department of Physics, Institute for Physical Science and Technology Biophysics Program, University of Maryland, College Park, Maryland 20742, USA.
authors: Michel
authors: M
authors: de Messieres
authors: Natalia A
authors: NA
authors: Denesyuk
authors: Arthur
authors: A
authors: La Porta
mesh_terms: D003198:Computer Simulation; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure*; D008956:Models, Chemical; D008958:Models, Molecular; D015233:Models, Statistical; D009690:Nucleic Acid Conformation; D052898:Optical Tweezers; D013314:Stress, Mechanical
chemical_list: D004247:DNA