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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-1203
DTSTART:20080918T150000Z
DURATION:PT1H0M0S
DTSTAMP:20260422T200520Z
LAST-MODIFIED:20080908T174356Z
LOCATION:5310 Chamberlin
SUMMARY:Quantum activation\, scaling\, and quantum measurements\, R. G
 . Herb Condensed Matter Seminar\, Mark Dykman\, Michigan State Univers
 ity
DESCRIPTION:Familiar mechanisms of metastable decay are tunneling and 
 thermal activation. We show that periodically modulated systems may di
 splay a different decay mechanism\, quantum activation. Here\, decay o
 ccurs via quantum fluctuations induced diffusion over a quasi-energy b
 arrier. We study quantum activation for nonlinear oscillators and show
  its unexpected features. The decay rate displays scaling behavior nea
 r critical parameter values where metastable vibrational states disapp
 ear. We also show that the tunnel splitting of symmetric and antisymme
 tric vibrational states oscillates and changes sign with varying param
 eters. The results impose limitations on the characteristics of bifurc
 ation amplifiers used in quantum measurements.
URL:https://www.physics.wisc.edu/events/?id=1203
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