@misc{oai:ir.soken.ac.jp:00000876, author = {LOUIS, Sebastien Gerald Roland and セバスチャン, ルイス and LOUIS, Sebastien Gerald Roland}, month = {2016-02-17, 2016-02-17}, note = {There are numerous proposals for the physical realization of a quantum
computer. However, distributed approaches, making use both of flying and
stationary qubits, seem to constitute the most promising route towards a
truly scalable device. Such systems guarantee extendibility, they incorpo-
rate the interface with communication applications and relax the physical
realization of the device, allowing for defect tolerance. Flying qubits are
included in the more general concept of a quantum bus, a mediating sys-
tem which can be of higher dimension. Such a quantum bus can be used
in the straightforward preparation of a standard multi-qubit resource en-
abling measurement based quantum computation, the cluster state. This
constitutes the framework for the results presented in this thesis.
 We begin by investigating the effects of dissipation in the continuous
variable bus scheme known as the qubus scheme. By considering loss in the
bus as it mediates interactions between the stationary qubits, we obtain an-
alytical results for the effective action of the induced quantum gate. We find
that a particular two-qubit gate operates with high fidelity in the presence
of moderate loss and give a simple iteration scheme to simplify the effects
of loss on the qubits. We then attempt to reduce these effects by preparing
the bus in more elaborate state, however no improvements are observed.
 We then apply the qubus scheme to the probabilistic generation of cluster
states and develop an entangling gate working with high success probability.
This allows us to produce cluster states far more efficiently than other pro-
posals. Investigating new methods to analyze the performance of different
generation strategies constitutes the second part of this set of results. We
begin by making the large flow approximation, used in queuing theory, to
obtain the optimal strategy in a regime with large resources. After what
we take the other more familiar limit of single cluster growth and introduce
absorbing Markov chains as a key mathematical tool.
 Finally we look at the transmission of composite quantum systems via a
single higher dimensional bus. We provide generalized protocols and inter-
actions guaranteeing a full transfer of the information from one composite
system to another. These protocols can also serve information process-
ing tasks, as useful logical operations can be applied to the data as it is
transfered. We notice lastly that the qubus scheme constitutes a potential
physical realization., application/pdf, 総研大甲第1201号}, title = {Distributed Hybrid Quantum Computing}, year = {} }