laboratoire pierre aigrain
électronique et photonique quantiques
 
laboratoire pierre aigrain
 

Seminar, 30th January 2017 (13h30 L363-365)

Loic Rondin (Laboratoire Aimé Cotton, Orsay)
Direct Measurement of Kramers’ Turnover with a Levitated Nanoparticle

Understanding the thermally activated escape from a metastable state is at the heart
of important phenomena such as the folding dynamics of proteins, the kinetics of chemical reactions or the stability of mechanical systems. In 1940 Kramers calculated escape rates both in the high damping and the low damping regime and suggested that the rate must have a maximum for intermediate damping. This phenomenon, today known as the Kramers turnover, has triggered important theoretical and
numerical studies. However, to date there is no direct and quantitative experimental
verification of this turnover. Using a nanoparticle trapped in a bi-stable optical potential we experimentally measure the nanoparticle’s transition rates for variable damping and directly resolve the Kramers turnover. Our measurements are in agreement with an analytical model that is free of adjustable parameters.