Konstantin Nestmann
Konstantin Nestmann
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Open Quantum Systems: Time (non)-locality, Fixed Points, and Renormalization Groups
In my doctoral thesis I considered the dynamics of open quantum systems from the quite different perspectives of quantum information theory and statistical physics.
K. Nestmann
Jul 2022
Dissertation
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DOI
Renormalization group for open quantum systems using environment temperature as flow parameter
We develop the $T$-flow renormalization group scheme to access the low-temperature many-body physics of open quantum systems by literally lowering the temperature of the environment.
K. Nestmann
,
M. R. Wegewijs
Apr 2022
SciPost Phys.
12
, 121
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DOI
General connection between time-local and time-nonlocal perturbation expansions
We show how to translate a perturbation expansion for the easier to compute time-nonlocal memory kernel $\mathcal{K}$ into a corresponding expansion for the more complicated time-local generator $\mathcal{G}$.
K. Nestmann
,
M. R. Wegewijs
Oct 2021
Phys. Rev. B
104
, 155407
·
Editor’s Suggestion
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Fermionic duality: General symmetry of open systems with strong dissipation and memory
We present intriguing exact relations between quantities that describe the time-evolution of quite generic open quantum systems. Combined with our fixed-point equation this leads to powerful insights into various approximation strategies.
V. Bruch
,
K. Nestmann
,
J. Schulenborg
,
M. R. Wegewijs
Sep 2021
SciPost Phys.
11
, 053
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How quantum evolution with memory is generated in a time-local way
We establish that the general connection between time-local and non-local quantum master equations is a simple yet general fixed-point equation with far reaching applications.
→ See press releases by
RWTH Aachen
,
FZ Jülich
and
JARA
K. Nestmann
,
V. Bruch
,
M. R. Wegewijs
May 2021
Phys. Rev. X
11
, 021041
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Five approaches to exact open-system dynamics: Complete positivity, divisibility, and time-dependent observables
We show that the “trivial” resonant level model actually provides a rich source of examples for interesting dynamics by solving it in 5 different ways.
V. Reimer
,
M. R. Wegewijs
,
K. Nestmann
,
M. Pletyukhov
Jul 2019
J. Chem. Phys.
151
, 044101
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