BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Thwarting long-lived dark states to speed up dynamic polarization 
 - Anushya Chandran (Boston University)
DTSTART:20210513T130000Z
DTEND:20210513T140000Z
UID:TALK156310@talks.cam.ac.uk
CONTACT:Jan Behrends
DESCRIPTION:Long-lived dark states\, in which an experimentally accessible
  qubit is not in thermal equilibrium with a surrounding spin bath\, are pe
 rvasive in solid-state systems. In the first half of the talk\, I will exp
 lain the ubiquity of dark states in a large class of inhomogenous central 
 spin models using the proximity to integrable lines with exact dark eigens
 tates. I will develop a picture of the eigenstates away from the integrabl
 e lines in terms of many-body resonances\, and argue that relaxation times
  are exponentially large in system size at accessible sizes. \n\nLong-live
 d dark states stymie hyperpolarization protocols that aim to transfer spin
  polarization from the central qubit to the surrounding spin bath. In the 
 second half of the talk\, I will describe fast and efficient hyperpolariza
 tion protocols that exploit certain integrability-breaking terms to reduce
  the statistical weight on dark states. These protocols use approximate co
 unter-diabatic driving and are experimentally accessible through Floquet e
 ngineering.
LOCATION:Details of video conferencing will be distributed nearer the time
 .
END:VEVENT
END:VCALENDAR