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BEGIN:VEVENT
UID:1-185@lptms.universite-paris-saclay.fr
DTSTART:20131119T110000Z
DTEND:20131119T120000Z
DTSTAMP:20131107T074848Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm
s-thomas-barthel/
SUMMARY:Séminaire du LPTMS: Thomas Barthel - LPTMS\, salle 201\, 2ème ét
age\, Bât 100\, Campus d'Orsay - 19 Nov 13 11:00
DESCRIPTION:Algebraic versus exponential decoherence in dissipative many-pa
rticle systems\nThomas Barthel\, LPTMS\nUltimately\, every quantum system
of interest is coupled to some form of environment which leads to decohere
nce. Until our recent study\, it was assumed that\, as long as the environ
ment is memory-less (i.e. Markovian)\, the temporal coherence decay is alw
ays exponential -- to a degree that this behavior was synonymously associa
ted with decoherence.\nHowever\, the situation can change if the system it
self is a many-body system. In this case\, the interplay between dissipati
on and internal interactions gives rise to a wealth of novel phenomena. In
particular\, the coherence decay can change to a power law.\nAfter recapi
tulating the mathematical framework and basic notions of decoherence\, I w
ill discuss an open XXZ chain for which the decoherence time diverges in t
he thermodynamic limit. The coherence decay is then algebraic instead of e
xponential. In contrast\, decoherence in the open transverse-field Ising m
odel is found to be always exponential. In this case\, the internal intera
ctions can both facilitate and impede the environment-induced decoherence.
The results are based on quasi-exact simulations using the time-dependent
density matrix renormalization group (tDMRG) and explained on the basis o
f perturbative treatments.\nReference: Z. Cai and T. Barthel\, PRL 111\, 1
50403 (2013)
LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15
Rue Georges Clemenceau\, Orsay\, 91405\, France
GEO:48.698185;2.181768
X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\,
Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è
me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768
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