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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-3727
DTSTART:20150709T150000Z
DURATION:PT1H0M0S
DTSTAMP:20210227T225535Z
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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