Xhek Turkeshi, Damien Barbier, Leticia F. Cugliandolo, Marco Schirò, Marco Tarzia
SciPost Phys. 12, 189 (2022) ·
published 9 June 2022
|
· pdf
We discuss and compare two recently proposed toy models for anomalous
transport and Griffiths effects in random systems near the Many-Body
Localization transitions: the random dephasing model, which adds thermal
inclusions in an Anderson Insulator as local Markovian dephasing channels that
heat up the system, and the random Gaussian Orthogonal Ensemble (GOE) approach
which models them in terms of ensembles of random regular graphs. For these two
settings we discuss and compare transport and dissipative properties and their
statistics. We show that both types of dissipation lead to similar
Griffiths-like phenomenology, with the GOE bath being less effective in
thermalising the system due to its finite bandwidth. We then extend these
models to the case of a quasi-periodic potential as described by the
André-Aubry-Harper model coupled to random thermal inclusions, that we show
to display, for large strength of the quasiperiodic potential, a similar
phenomenology to the one of the purely random case. In particular, we show the
emergence of subdiffusive transport and broad statistics of the local density
of states, suggestive of Griffiths like effects arising from the interplay
between quasiperiodic localization and random coupling to the baths.
Dainius Kilda, Alberto Biella, Marco Schiro, Rosario Fazio, Jonathan Keeling
SciPost Phys. Core 4, 005 (2021) ·
published 24 February 2021
|
· pdf
We present calculations of the time-evolution of the driven-dissipative XYZ model using the infinite Projected Entangled Pair Operator (iPEPO) method, introduced by [A. Kshetrimayum, H. Weimer and R. Orús, Nat. Commun. 8, 1291 (2017)]. We explore the conditions under which this approach reaches a steady state. In particular, we study the conditions where apparently converged calculations may become unstable with increasing bond dimension of the tensor-network ansatz. We discuss how more reliable results could be obtained.
Lorenzo Rosso, Fernando Iemini, Marco Schirò, Leonardo Mazza
SciPost Phys. 9, 091 (2020) ·
published 29 December 2020
|
· pdf
We generalize the theory of flow equations to open quantum systems focusing
on Lindblad master equations. We introduce and discuss three different
generators of the flow that transform a linear non-Hermitian operator into a
diagonal one. We first test our dissipative flow equations on a generic matrix
and on a physical problem with a driven-dissipative single fermionic mode. We
then move to problems with many fermionic modes and discuss the interplay
between coherent (disordered) dynamics and localized losses. Our method can
also be applied to non-Hermitian Hamiltonians.
Submissions
Submissions for which this Contributor is identified as an author: