Advanced

Can we always get the entanglement entropy from the Kadanoff-Baym equations? The case of the T-matrix approximation

Puig von Friesen, Marc LU ; Verdozzi, Claudio LU and Almbladh, Carl-Olof LU (2011) In Europhysics Letters 95(2).
Abstract
We study the time-dependent transmission of entanglement entropy through an out-of-equilibrium model interacting device in a quantum transport set-up. The dynamics is performed via the Kadanoff-Baym equations within many-body perturbation theory. The double occupancy <(n) over cap (R dagger)(n) over cap (R down arrow)>, needed to determine the entanglement entropy, is obtained from the equations of motion of the single-particle Green's function. A remarkable result of our calculations is that <(n) over cap (R dagger)(n) over cap (R down arrow)> can become negative, thus not permitting to evaluate the entanglement entropy. This is a shortcoming of approximate, and yet conserving, many-body self-energies. Among the tested... (More)
We study the time-dependent transmission of entanglement entropy through an out-of-equilibrium model interacting device in a quantum transport set-up. The dynamics is performed via the Kadanoff-Baym equations within many-body perturbation theory. The double occupancy <(n) over cap (R dagger)(n) over cap (R down arrow)>, needed to determine the entanglement entropy, is obtained from the equations of motion of the single-particle Green's function. A remarkable result of our calculations is that <(n) over cap (R dagger)(n) over cap (R down arrow)> can become negative, thus not permitting to evaluate the entanglement entropy. This is a shortcoming of approximate, and yet conserving, many-body self-energies. Among the tested perturbation schemes, the T-matrix approximation stands out for two reasons: it compares well to exact results in the low-density regime and it always provides a non-negative <(n) over cap (R dagger)(n) over cap (R down arrow)> For the second part of this statement, we give an analytical proof. Finally, the transmission of entanglement across the device is diminished by interactions but can be amplified by a current flowing through the system. Copyright (C) EPLA, 2011 (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Europhysics Letters
volume
95
issue
2
publisher
EDP Sciences
external identifiers
  • wos:000292384900024
  • scopus:79960153949
ISSN
0295-5075
DOI
10.1209/0295-5075/95/27005
language
English
LU publication?
yes
id
58f43f29-ae38-4570-b6d0-b4191501d847 (old id 2032317)
date added to LUP
2011-07-26 15:00:37
date last changed
2017-06-04 03:14:26
@article{58f43f29-ae38-4570-b6d0-b4191501d847,
  abstract     = {We study the time-dependent transmission of entanglement entropy through an out-of-equilibrium model interacting device in a quantum transport set-up. The dynamics is performed via the Kadanoff-Baym equations within many-body perturbation theory. The double occupancy &lt;(n) over cap (R dagger)(n) over cap (R down arrow)&gt;, needed to determine the entanglement entropy, is obtained from the equations of motion of the single-particle Green's function. A remarkable result of our calculations is that &lt;(n) over cap (R dagger)(n) over cap (R down arrow)&gt; can become negative, thus not permitting to evaluate the entanglement entropy. This is a shortcoming of approximate, and yet conserving, many-body self-energies. Among the tested perturbation schemes, the T-matrix approximation stands out for two reasons: it compares well to exact results in the low-density regime and it always provides a non-negative &lt;(n) over cap (R dagger)(n) over cap (R down arrow)&gt; For the second part of this statement, we give an analytical proof. Finally, the transmission of entanglement across the device is diminished by interactions but can be amplified by a current flowing through the system. Copyright (C) EPLA, 2011},
  articleno    = {27005},
  author       = {Puig von Friesen, Marc and Verdozzi, Claudio and Almbladh, Carl-Olof},
  issn         = {0295-5075},
  language     = {eng},
  number       = {2},
  publisher    = {EDP Sciences},
  series       = {Europhysics Letters},
  title        = {Can we always get the entanglement entropy from the Kadanoff-Baym equations? The case of the T-matrix approximation},
  url          = {http://dx.doi.org/10.1209/0295-5075/95/27005},
  volume       = {95},
  year         = {2011},
}