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SUMMARY:Arrow of time and entropy production in active fluctuations - Edga
 r Roldan (ICTP\, Trieste\, Italy)
DTSTART:20190312T130000Z
DTEND:20190312T140000Z
UID:TALK116044@talks.cam.ac.uk
CONTACT:Professor Mike Cates
DESCRIPTION:Active systems are maintained out of equilibrium by processes 
 that consume resources of energy and produce entropy.  A well studied exam
 ple of active cellular fluctuations are spontaneous oscillations of mechan
 osensory hair bundles of auditory hair cells.  Active processes do not obe
 y in general the fluctuation-dissipation theorem: measuring both the linea
 r response of the system to weak external stimuli and spontaneous fluctuat
 ions provides a means to quantify deviations from thermal equilibrium.   F
 or active fluctuations without drift\, such as spontaneous oscillations\, 
 it is unclear how entropy production can be characterized.\n\nWe introduce
  lower bounds for the rate of entropy production of an active process by q
 uantifying the degree of time irreversibility of stochastic traces obtaine
 d from non-equilibrium mesoscopic degrees of freedom [1].  Our measures of
  irreversibility reveal signatures of time’s arrow and provide bounds fo
 r entropy production even in the case of active fluctuations that have no 
 drift. We apply these irreversibility measures to experimental recordings 
 of ~200 spontaneous hair-bundle oscillations from the ear of the bullfrog 
 Rana Catesbeiana. Our technique allows not only to discriminate between ex
 perimental recordings of active and passive hair-bundle oscillations but a
 lso to estimate the minimal entropy production required to sustain such os
 cillations. Notably\, our approach can be applied to any physical system w
 here at least one mesoscopic degree of freedom that is even under time rev
 ersal can be measured experimentally.\n\n[1] É. Roldán\, J. Barral\, P. 
 Martin\, J.M.R. Parrondo and F. Jülicher\narXiv:1801.01574 (2018).\n
LOCATION:MR11\, CMS
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