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UID:0-770@lptms.universite-paris-saclay.fr
DTSTART;TZID=Europe/Paris:20210518T110000
DTEND;TZID=Europe/Paris:20210518T120000
DTSTAMP:20210506T110419Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm
s-orazio-scarlatella-college-de-france/
SUMMARY:Séminaire du LPTMS : Orazio Scarlatella (Collège de France) - LPT
MS (100% online seminar) - 18 Mai 21 11:00
DESCRIPTION:Dynamical Mean-Field Theory for Markovian Open Quantum Many-Bod
y Systems\nOrazio Scarlatella (Collège de France)\n\nOnline seminar --- Z
oom Meeting ID: 962 2949 3343 -- Passcode: ask L. Mazza and D. Petrov --\n
\nMarkovian quantum many body systems describe a number of experimental pl
atforms relevant for quantum simulations. Their theoretical understanding
is hampered by the exponential scaling of their Hilbert space and by their
intrinsic nonequilibrium nature\, limiting the applicability of many trad
itional approaches. In this talk I will present an extension of the nonequ
ilibrium Dynamical Mean Field Theory (DMFT) to bosonic Markovian open quan
tum systems. Within DMFT\, a Lindblad master equation describing a lattice
of dissipative particles is mapped onto an impurity problem describing a
single site of the lattice coupled to a self-consistent environment\, whic
h for bosons accounts for fluctuations beyond Gutzwiller mean-field theory
due to the finite lattice connectivity. I will present a non-perturbative
approach to solve this impurity problem\, which is tailored for Markovian
open quantum systems. As a first application of this DMFT approach\, I wi
ll discuss the steady-state of a driven-dissipative Bose-Hubbard model wit
h two-body losses and incoherent pump. I will show that this model feature
s a normal phase at small hopping and a phase transition towards a non-equ
ilibrium superfluid. Remarkably\, this transition occurs as a finite-frequ
ency instability\, leading to an oscillating in time order parameter. Then
\, I will show that DMFT captures hopping-induced dissipative processes\,
completely missed in Gutzwiller mean-field theory\, which crucially determ
ine the properties of the normal phase\, including the suppression of loca
l gain and the emergence of a stationary quantum-Zeno regime. I will also
argue that these processes compete with coherent hopping processes to dete
rmine the phase transition towards the superfluid phase\, leading to a lar
ge extension of the normal phase due to finite-connectivity.
CATEGORIES:seminars
LOCATION:LPTMS (100% online seminar)\, LPTMS - Bâtiment Pascal n° 530 rue
André Rivière - Université Paris-Saclay\, Orsay\, 91405\, France
X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=LPTMS - Bâtiment Pascal n
° 530 rue André Rivière - Université Paris-Saclay\, Orsay\, 91405\, Fr
ance;X-APPLE-RADIUS=100;X-TITLE=LPTMS (100% online seminar):geo:0,0
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