60 research outputs found
Robust and Scalable Scheme to Generate Large-Scale Entanglement Webs
We propose a robust and scalable scheme to generate an -qubit state
among separated quantum nodes (cavity-QED systems) by using linear optics and
postselections. The present scheme inherits the robustness of the Barrett-Kok
scheme [Phys. Rev. A {\bf 71}, 060310(R) (2005)]. The scalability is also
ensured in the sense that an arbitrarily large -qubit state can be
generated with a quasi-polynomial overhead . The
process to breed the states, which we introduce to achieve the scalability,
is quite simple and efficient, and can be applied for other physical systems.Comment: 5 pages, 3 figure
Efficient Concentration Protocols for the Single-Photon Entanglement State with Polarization Feature
We propose two efficient entanglement concentration protocols (ECPs) for arbitrary less-entangled single-photon entanglement state, in which the photon qubit has the polarization feature. The first ECP is in linear optics, and the second ECP is in nonlinear optics. The two ECPs have some attractive advantages. First, they can preserve the polarization feature of the photon qubit, while all the other existing ECPs for single photon state cannot achieve this goal. Second, they only require one pair of less-entangled single-photon entanglement state and some auxiliary single photons. Third, they only require local operations. Especially, the second ECP can be used repeatedly, which can increase its success probability largely. Based on above properties, our two ECPs, especially the second one may be useful in current and future quantum communication
Parity-encoding-based quantum computing with Bayesian error tracking
Measurement-based quantum computing (MBQC) in linear optical systems is
promising for near-future quantum computing architecture. However, the
nondeterministic nature of entangling operations and photon losses hinder the
large-scale generation of graph states and introduce logical errors. In this
work, we propose a linear optical topological MBQC protocol employing
multiphoton qubits based on the parity encoding, which turns out to be highly
photon-loss tolerant and resource-efficient even under the effects of nonideal
entangling operations that unavoidably corrupt nearby qubits. For the realistic
error analysis, we introduce a Bayesian methodology, in conjunction with the
stabilizer formalism, to track errors caused by such detrimental effects. We
additionally suggest a graph-theoretical optimization scheme for the process of
constructing an arbitrary graph state, which greatly reduces its resource
overhead. Notably, we show that our protocol is advantageous over several other
existing approaches in terms of fault-tolerance, resource overhead, or
feasibility of basic elements.Comment: Main text: 15 pages, 10 figures / Supplemental Material: 17 pages, 8
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