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@MASTERSTHESIS{Hobl:276310,
author = {Hobl, Lukas},
title = {{S}imulating on the {D}-{W}ave {T}wo and emulating its
behavior on an ordinary computer},
school = {RWTH Aachen},
type = {MS},
reportid = {FZJ-2015-06771},
pages = {64 p.},
year = {2015},
note = {RWTH Aachen, Masterarbeit, 2015},
abstract = {This work presents the results of random spanning tree and
2-SAT problems, which weresolved using a D-Wave Two
processor.Firstly, the results for random spanning tree
problems, translated to Ising spin problemsare discussed.
The results suggest that the Z2-symmetry of the Ising spin
systemimplemented on the D-Wave Two processor is severely
broken. It is furthermore shown,that isolated regions of
qubits on the D-Wave Two processor behave statistically
independent.A date and time dependency of the solution
frequency is observed as the solutionfrequency of the same
problem on different days differs significantly with respect
to thestatistical errors.When starting to operate on a new
D-Wave processor, the random spanning tree problemspresented
in this work can be used as good test cases that allow
obtaining basicinformation on the processor’s
characteristics. The results of the random spanning
treeproblem also suggest that, in order to get statistically
reproducible results, computationson the D-Wave Two
processor need to be performed over long time periods and in
differentregions of the processor.Secondly, the solving
frequencies for 2-SAT problems with very small minimum
gapssolved on the D-Wave Two processor are compared to those
obtained via emulation i.e.simulation of the actual physical
behavior of the D-Wave Two quantum processor on aclassical
computer. A comparison of the solving frequencies shows,
that 2-SAT problemswith minimum gaps larger than the
operating temperature of the D-Wave Two processorare solved
by quantum annealing. For problems with minimum gaps
significantly smallerthan the operating temperature of the
D-Wave Two processor, the results suggest thatfinding a
solution is assisted by thermal effects. For problems with
minimum gaps close tothe operating temperature of the D-Wave
Two processor, a transition between the quantumannealing
process and the thermally assisted process can be assumed.In
order to gain a more detailed insight into the behavior of
the D-Wave Two processor,further studies of the 2-SAT
problems are planned. An investigation of additionalproblems
in the area of transition is expected to deliver a better
understanding of the prevailingprocesses. It should also be
of interest to investigate at what point a problem with
asmaller minimum gap than the processor’s operating
temperature would lead to a decreaserather than an increase
of the solution frequency. A decrease of the solution
frequency isexpected since the energy barriers between
states are so small that the likelihood of thermaloccupation
of exited states increases and also that calibration errors
of the D-WaveTwo processor become more dominant.},
cin = {JSC},
cid = {I:(DE-Juel1)JSC-20090406},
pnm = {511 - Computational Science and Mathematical Methods
(POF3-511)},
pid = {G:(DE-HGF)POF3-511},
typ = {PUB:(DE-HGF)19},
url = {https://juser.fz-juelich.de/record/276310},
}