Fwd: [Cmsp-seminars] REMINDER New Cycle of Cond Mat Seminars @ SISSA - TODAY 11:30 Room 128

[Condensed Matter Section]

-------- Forwarded Message --------
Subject: 	[Cmsp-seminars] REMINDER New Cycle of Cond Mat Seminars @ 
SISSA - TODAY 11:30 Room 128
Date: 	Thu, 19 Nov 2015 08:49:26 +0100
From: 	Francesco Peronaci <fperonaci at sissa.it>
To: 	cmsp-seminar at lists.ictp.it


NEW CYCLE OF CONDENSED MATTER SEMINARS


Martin Eckstein (Max Planck Research Department for Structural
Dynamics, University of Hamburg-CFEL)

TITLE: Photo-induced metal-insulator transitions - how fast does the
quasiparticle peak form in the Hubbard model

Thursday 19th November 2015 at 11:30 AM

SISSA Santorio building Room 129

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Femtosecond pump-probe experiments make it possible to access the
dynamics of complex condensed matter phases on microscopic timescales.
In this talk I discuss resent work on time-dependent metal insulator
transitions, based on the nonequilibrium generalization of dynamical
mean-field theory (DMFT) [1]. When the Mott transition is approached
from the metallic side, a narrow quasi-particle band emerges at the
Fermi energy, which gives way to a bad metal at high temperature. We
can imagine a simple thought experiment in which the quasiparticle
band is destroyed by a strong excitation, and reforms as the
excitation energy is passed from the electrons to the lattice. This
leads to the fundamental question how fast coherent quasi-particles
can be born out of the bad metal. Within DMFT, the quasiparticle peak
corresponds to the Kondo resonance in an effective Anderson impurity
model, and the timescale for the formation of the latter was found to
be "uncertainty limited", i.e., it is given by the inverse width of
the peak itself. The behavior is however entirely different for the
formation of the quasiparticle band, as the spectral weight
responsible for the Kondo screening has to be formed
self-consistently, leading to a considerable slowing down of the
dynamics towards the metal-insulator transition.

[1] H. Aoki et al, Rev. Mod. Phys. 86, 779 (2014).

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