mirror of
https://github.com/vale981/master-thesis-tex
synced 2025-03-04 17:21:37 -05:00
first crack at a summary
This commit is contained in:
parent
c4c65089ed
commit
bd74375c0d
1 changed files with 61 additions and 1 deletions
|
@ -1,5 +1,65 @@
|
||||||
\chapter{Conclusion and Ideas for future Work}
|
\chapter{Conclusion and Outlook}
|
||||||
\label{cha:concl-ideas-future}
|
\label{cha:concl-ideas-future}
|
||||||
|
|
||||||
|
In this work, we set out to find a way of accessing bath related
|
||||||
|
observables, such as the expected bath energy change and the
|
||||||
|
interaction energy expectation value, using the
|
||||||
|
NMQSD\footnote{Non-Markovian Quantum State
|
||||||
|
Diffusion}/HOPS\footnote{Hierarchy of Pure States} framework which
|
||||||
|
we introduced in \cref{chap:intro}. This endeavor was indeed
|
||||||
|
successful as was laid out in \cref{chap:flow}.
|
||||||
|
|
||||||
|
In \cref{chap:flow} we presented a solution to a well known model for
|
||||||
|
quantum Brownian motion. Using this solution, we were able to derive
|
||||||
|
expressions for the bath energy change \(∂_{t}\ev{H_{\bath}}\).
|
||||||
|
|
||||||
|
This enabled us to verify the results of \cref{chap:flow} in
|
||||||
|
\cref{chap:numres} by solving the same model numerically using
|
||||||
|
HOPS. Excellent agreement was found in
|
||||||
|
\cref{sec:hopsvsanalyt}.
|
||||||
|
|
||||||
|
Turning to the spin-boson model in \cref{sec:prec_sim}, we used energy
|
||||||
|
conservation to verify again, that we can consistently and efficiently
|
||||||
|
compute bath related observables with HOPS. In the cases where the
|
||||||
|
consistency condition was not met, we nevertheless found that
|
||||||
|
qualitatively correct results had been reached. The direct calculation
|
||||||
|
of the interaction energy by the use of \cref{sec:intener} gives
|
||||||
|
results that are more precise than the ones obtained through energy
|
||||||
|
conservation.
|
||||||
|
|
||||||
|
We continued to explore the energy transfer behavior of the zero
|
||||||
|
temperature spin-boson model and found that energy transfer
|
||||||
|
performance for strong coupling has a complicated dependence on the
|
||||||
|
spectral density of the bath. Energy transfer performance can be
|
||||||
|
optimized longer bath memories and resonant baths when the interaction
|
||||||
|
is turned off at the right time.
|
||||||
|
|
||||||
|
The short time dynamics of the bath energy change can be explained by
|
||||||
|
neglecting the system Hamiltonian, which we verified for the
|
||||||
|
spin-boson model. It was also found, that this short time behaviour is
|
||||||
|
already present on the trajectory level so that there are no
|
||||||
|
stochastic fluctuations for short times. During this initial period,
|
||||||
|
the auxiliary states of the HOPS are being populated.
|
||||||
|
|
||||||
|
In \cref{sec:singlemod} we turned to issues of quantum
|
||||||
|
thermodynamics. We reviewed some general analytical results that
|
||||||
|
bounded energy extraction from open systems in
|
||||||
|
\cref{sec:basic_thermo}, both for the single-bath and the multi-bath
|
||||||
|
case. We then turned to some more challenging applications of the HOPS
|
||||||
|
method. First, a driven spin-boson model was considered. We found that
|
||||||
|
a not insignificant fraction of the theoretical maximum of energy can
|
||||||
|
be extracted by modulating the coupling and providing a bath with long
|
||||||
|
memory time. We also demonstrated quantum friction, a quantum speed
|
||||||
|
limit and a bath resonance phenomenon.
|
||||||
|
|
||||||
|
Finally, we treated a model with multiple baths in \cref{sec:otto} and
|
||||||
|
non-harmonic smooth modulation. A cyclic modulation protocol was
|
||||||
|
implemented upon a two level system coupled to two baths in a
|
||||||
|
spin-boson like fashion. We achieved finite power with finite
|
||||||
|
efficiency and verified a Gibbs-like inequality
|
||||||
|
\cref{sec:operational_thermo}. When disabling the coupling modulation,
|
||||||
|
the power and efficiency were much reduced.
|
||||||
|
|
||||||
A worthwhile task for future work would be to verify the results
|
A worthwhile task for future work would be to verify the results
|
||||||
summarized in \refcite{Binder2018} for the Otto cycle. Especially the
|
summarized in \refcite{Binder2018} for the Otto cycle. Especially the
|
||||||
optimization for optimal power which leads to the
|
optimization for optimal power which leads to the
|
||||||
|
|
Loading…
Add table
Reference in a new issue