Bistabilities and domain walls in weakly open quantum systems
Weakly pumped systems with approximate conservation laws can be efficiently described by a generalized Gibbs ensemble if the steady state of the system is unique. However, such a description can fail if there are multiple steady state solutions, for example, a bistability. In this case domains an...
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doaj-de6e08c16b094e56963114be279046f42020-11-25T03:56:36ZengSciPostSciPost Physics2542-46532020-10-019405710.21468/SciPostPhys.9.4.057Bistabilities and domain walls in weakly open quantum systemsFlorian Lange, Achim RoschWeakly pumped systems with approximate conservation laws can be efficiently described by a generalized Gibbs ensemble if the steady state of the system is unique. However, such a description can fail if there are multiple steady state solutions, for example, a bistability. In this case domains and domain walls may form. In one-dimensional (1D) systems any type of noise (thermal or non-thermal) will in general lead to a proliferation of such domains. We study this physics in a 1D spin chain with two approximate conservation laws, energy and the $z$-component of the total magnetization. A bistability in the magnetization is induced by the coupling to suitably chosen Lindblad operators. We analyze the theory for a weak coupling strength $\epsilon$ to the non-equilibrium bath. In this limit, we argue that one can use hydrodynamic approximations which describe the system locally in terms of space- and time-dependent Lagrange parameters. Here noise terms enforce the creation of domains, where the typical width of a domain wall goes as $\sim 1/\sqrt{\epsilon}$ while the density of domain walls is exponentially small in $1/\sqrt{\epsilon}$. This is shown by numerical simulations of a simplified hydrodynamic equation in the presence of noise.https://scipost.org/SciPostPhys.9.4.057 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Florian Lange, Achim Rosch |
spellingShingle |
Florian Lange, Achim Rosch Bistabilities and domain walls in weakly open quantum systems SciPost Physics |
author_facet |
Florian Lange, Achim Rosch |
author_sort |
Florian Lange, Achim Rosch |
title |
Bistabilities and domain walls in weakly open quantum systems |
title_short |
Bistabilities and domain walls in weakly open quantum systems |
title_full |
Bistabilities and domain walls in weakly open quantum systems |
title_fullStr |
Bistabilities and domain walls in weakly open quantum systems |
title_full_unstemmed |
Bistabilities and domain walls in weakly open quantum systems |
title_sort |
bistabilities and domain walls in weakly open quantum systems |
publisher |
SciPost |
series |
SciPost Physics |
issn |
2542-4653 |
publishDate |
2020-10-01 |
description |
Weakly pumped systems with approximate conservation laws can be efficiently
described by a generalized Gibbs ensemble if the steady state of the system is
unique. However, such a description can fail if there are multiple steady state
solutions, for example, a bistability. In this case domains and domain walls
may form. In one-dimensional (1D) systems any type of noise (thermal or
non-thermal) will in general lead to a proliferation of such domains. We study
this physics in a 1D spin chain with two approximate conservation laws, energy
and the $z$-component of the total magnetization. A bistability in the
magnetization is induced by the coupling to suitably chosen Lindblad operators.
We analyze the theory for a weak coupling strength $\epsilon$ to the
non-equilibrium bath. In this limit, we argue that one can use hydrodynamic
approximations which describe the system locally in terms of space- and
time-dependent Lagrange parameters. Here noise terms enforce the creation of
domains, where the typical width of a domain wall goes as $\sim
1/\sqrt{\epsilon}$ while the density of domain walls is exponentially small in
$1/\sqrt{\epsilon}$. This is shown by numerical simulations of a simplified
hydrodynamic equation in the presence of noise. |
url |
https://scipost.org/SciPostPhys.9.4.057 |
work_keys_str_mv |
AT florianlangeachimrosch bistabilitiesanddomainwallsinweaklyopenquantumsystems |
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1724464033140047872 |