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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-2588
DTSTART:20121207T213000Z
DURATION:PT1H0M0S
DTSTAMP:20260412T132948Z
LAST-MODIFIED:20121203T161401Z
LOCATION:2241 Chamberlin Hall (coffee at 4:30 pm)
SUMMARY:Testing Landauer’s Principle in a feedback trap\, Physics De
 partment Colloquium\, John Bechhoefer\, Simon Fraser University
DESCRIPTION:Landauer's principle\, formulated in 1961\, postulates tha
 t irreversible logical or computational operations such as memory eras
 ure require work\, no matter how slowly they are performed.  For examp
 le\, to "reset to one" a one-bit memory  requires a work of at least k
 T ln2\, which is dissipated as heat.  In 1982\, Bennett pointed out a 
 link to Maxwell's Demon:  Were Landauer's principle to fail\, it would
  be possible to repeatedly extract work from a heat bath.<br>
\n<br>
\
 nWe report tests of Landauer's principle in an experimental system\, w
 here a "virtual"  double-well potential is created via a feedback loop
 .  We observe the position of a charged\, fluorescent\, colloidal part
 icle in water and calculate and then apply the appropriate force using
  an electric field.  In a first experiment\, the probability of "erasu
 re" (resetting to one) is unity\, and at long cycle times\, we observe
  that the work is compatible with kT ln2.  In a second\, the probabili
 ty of erasure is zero\; the system may end up in two states\; and\, at
  long cycle times\, the measured work tends to zero.<br>
\n
URL:https://www.physics.wisc.edu/events/?id=2588
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