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PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-3727
DTSTART:20150709T150000Z
DURATION:PT1H0M0S
DTSTAMP:20260419T124516Z
LAST-MODIFIED:20150611T151905Z
LOCATION:5310 Chamberlin Hall
SUMMARY:Multi-qubit quantum co-tunneling as a computational resource\,
  R. G. Herb Condensed Matter Seminar\,  Kostya Kechedzhi
DESCRIPTION:Recently\, a number of hardware platforms became available
  where large scale complex quantum spin system dynamics (such as a qua
 ntum spin glass) could potentially be addressed experimentally\, inclu
 ding trapped ions systems and superconducting circuits. From the theor
 etical point of view\, analysis of the dynamics of such complex system
 s is challenging and therefore we take the so called "bottom up" appro
 ach.  We analyze simple models that are analytically tractable and at 
 the same time retain key features of the complex spin models\, with th
 e idea of developing some intuition that can be applied in more realis
 tic cases. In this spirit\, I will discuss a specific model\, a fully 
 connected cluster of spins with uniform interactions (uniform p-spin m
 odel)\, and describe its dynamics including the effects of multiqubit 
 quantum co-tunneling at finite temperature. One question we are partic
 ularly interested in in this work is the role the extensive quantum tu
 nneling could play in quantum computation. Quantum annealing algorithm
  proposed by Nishimori and coauthors PRE (1992) relies on quantum tunn
 eling and has been conjectured to improve upon the performance of clas
 sical simulated annealing\, an algorithm designed to solve complex opt
 imization NP-hard problems (such as finding a ground state of a spin g
 lass). Using the example of the uniform p-spin model we will show that
   quantum annealing algorithm relying on extensive incoherent co-tunne
 ling and thermalization dynamics could outperform the standard simulat
 ed annealing in a range of parameters.
URL:https://www.physics.wisc.edu/events/?id=3727
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