Concentrating partially entangled W-class states on nonlocal atoms using low-Q optical cavity and linear optical elements

Cao, Cong; Chen, Xi; Duan, Yucong; Fan, Ling; Zhang, Ru; Wang, Zhihui; Wang, Chuan

doi:10.1007/s11433-016-0253-x

Cited by 50 publications

(23 citation statements)

References 71 publications

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“…Entanglement purification 24 – 28 is applied to extract high-fidelity maximally entangled states from mixed entangled states. Entanglement concentration 29 – 45 is often used to distill less-entangled states into pure maximally entangled states by local operations and classical communication (i.e. LOCC).…”

Section: Resultsmentioning

confidence: 99%

Greenberger-Horne-Zeilinger states-based blind quantum computation with entanglement concentration

Zhang

Weng

et al. 2017

Sci Rep

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In blind quantum computation (BQC) protocol, the quantum computability of servers are complicated and powerful, while the clients are not. It is still a challenge for clients to delegate quantum computation to servers and keep the clients’ inputs, outputs and algorithms private. Unfortunately, quantum channel noise is unavoidable in the practical transmission. In this paper, a novel BQC protocol based on maximally entangled Greenberger-Horne-Zeilinger (GHZ) states is proposed which doesn’t need a trusted center. The protocol includes a client and two servers, where the client only needs to own quantum channels with two servers who have full-advantage quantum computers. Two servers perform entanglement concentration used to remove the noise, where the success probability can almost reach 100% in theory. But they learn nothing in the process of concentration because of the no-signaling principle, so this BQC protocol is secure and feasible.

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Section: Resultsmentioning

confidence: 99%

Greenberger-Horne-Zeilinger states-based blind quantum computation with entanglement concentration

Zhang

Weng

et al. 2017

Sci Rep

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“…On the other hand, environmental noise will degrade the maximally entangled state j/ þ i to a mixed state. Fortunately, entanglement purification and concentration provided us the powerful tool to recover the low quality entangled states to the high quality entangled state [48][49][50][51][52][53].…”

Section: Discussionmentioning

confidence: 99%

Distributed secure quantum machine learning

2017

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“…Similarly, after the photon passes through the block composed of CPBS 3 , QD 2 , WFC, and CPBS 4 , as well as two spin Hadamard operations, the composite system is in the state (without normalization)

\begin{matrix} true \\ right r^{2} [|R〉 {(|〉 ↑)}_{1} false(α_{1} {|↑〉}_{2} + α_{2} {|↓〉}_{2} false) + |L〉 {(|〉 ↓)}_{1} false(α_{3} {|↓〉}_{2} + α_{4} {|↑〉}_{2} false)] \end{matrix}

and the fidelity of the quantum gate operation is increased to unity assisted by the WFC. We note that the WFC, for example, the unbalanced beam splitter, has been widely used to design high‐fidelity QIP schemes . On the other hand, the efficiency of the quantum gate may be reduced by this method.…”

Section: Discussion and Summarymentioning

confidence: 99%

“…Through a circular polarizing beam splitter CPBS 1 , the L ‐polarized component of the photon is reflected to spatial mode u for interacting with the QD 1 under the balance condition, while the R ‐polarized photon component is transmitted to spatial mode d . WFC in the spatial mode d represents a waveform corrector (e.g., an unbalanced beam splitter with the reflection coefficient r ), which is used to map

{false| R false⟩}_{d}

{r false| R false⟩}_{d}

. After the photon components emitting from the spatial modes u and d arrive at CPBS 2 simultaneously, a polarization Hadamard operation [

false| R false⟩ \leftrightarrow false(false| R false⟩ + false| L false⟩ false) / \sqrt{2}

and

false| L false⟩ \leftrightarrow false(false| R false⟩ - false| L false⟩ false) / \sqrt{2}

] is performed on the photon through a half‐wave plate HWP oriented at 22.5°.…”

Section: Cnot Gate On Two Electron‐spin Qubits In Two Qd‐cavity Systemsmentioning

confidence: 99%

High‐Fidelity Universal Quantum Controlled Gates on Electron‐Spin Qubits in Quantum Dots Inside Single‐Sided Optical Microcavities

et al. 2019

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Semiconductor quantum‐dot (QD) spins hold great promise in quantum information science and technology. The implementation of high‐fidelity quantum gates on QD‐spin qubits is of great importance. Here, two schemes are presented to implement two universal quantum controlled gates, that is, the two‐qubit controlled‐not gate and the three‐qubit Toffoli gate, on stationary electron‐spin qubits in QDs inside single‐sided optical microcavities, based on the cavity‐assisted photon scattering under the balance condition. Compared with the previous schemes based on the ideal giant circular birefringence, the present schemes use the balance condition of the single‐sided QD‐cavity system, which can be achieved in both the weak‐ and strong‐coupling regimes of cavity quantum electrodynamics. Under the balance condition, the noise caused by the unbalanced reflectance between the coupled and uncoupled QD‐cavity systems can be efficiently depressed, so that the fidelity of each quantum gate operation can be increased to unity in principle. The schemes exhibit the possibility of realizing high‐fidelity and scalable quantum computing with single QD spins and single photons using the feasible and robust light–matter quantum interface. These high‐fidelity quantum controlled gates can lead to more efficient construction of quantum circuits for quantum computing, and provide a convenient avenue for quantum networking.

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Concentrating partially entangled W-class states on nonlocal atoms using low-Q optical cavity and linear optical elements

Cited by 50 publications

References 71 publications

Greenberger-Horne-Zeilinger states-based blind quantum computation with entanglement concentration

Greenberger-Horne-Zeilinger states-based blind quantum computation with entanglement concentration

Distributed secure quantum machine learning

High‐Fidelity Universal Quantum Controlled Gates on Electron‐Spin Qubits in Quantum Dots Inside Single‐Sided Optical Microcavities

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