arXiv subjects

Wen-Bo Xing

Publications and source records attributed to Wen-Bo Xing.

8 recordsLinked to original sources

arXiv2025

Practical Advantage of Classical Communication in Entanglement Detection

Entanglement is the cornerstone of quantum communication, yet conventional detection relies solely on local measurements. In this work, we present a unified theoretical and experimental framework demonstrating that one-way local operations and classical communication (1-LOCC) can significantly outperform purely local measurements in detecting high-dimensional quantum entanglement. By casting the entanglement detection problem as a semidefinite program (SDP), we derive protocols that minimize false negatives at fixed false-positive rates. A variational generative machine-learning algorithm efficiently searches over high-dimensional parameter spaces, identifying states and measurement strategies that exhibit a clear 1-LOCC advantage. Experimentally, we realize a genuine event-ready protocol on a three-dimensional photonic entanglement source, employing fiber delays as short-lived quantum memories. We implement rapid, FPGA-based sampling of the optimized probabilistic instructions, allowing Bob's measurement settings to adapt to Alice's outcomes in real time. Our results validate the predicted 1-LOCC advantage in a realistic noisy setting and reduce the experimental trials needed to certify entanglement. These findings mark a step toward scalable, adaptive entanglement detection methods crucial for quantum networks and computing, paving the way for more efficient generation and verification of high-dimensional entangled states.

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arXiv2023

Preparation of multiphoton high-dimensional GHZ state

Multipartite high-dimensional entanglement presents different physics from multipartite two-dimensional entanglement. However, how to prepare multipartite high-dimensional entanglement is still a challenge with linear optics. In this paper, a multiphoton GHZ state with arbitrary dimensions preparation protocol is proposed in optical systems. In this protocol, we use auxiliary entanglements to realize a high-dimensional entanglement gate, so that high-dimensional entangled pairs can be connected into a multipartite high-dimensional GHZ state. Specifically, we give an example of using photons' path degree of freedom to prepare a 4-particle 3-dimensional GHZ state. Our method can be extended to other degrees of freedom and can generate arbitrary GHZ entanglement in any dimension.

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arXiv2021

Optimized detection of high-dimensional entanglement

Entanglement detection is one of the most conventional tasks in quantum information processing. While most experimental demonstrations of high-dimensional entanglement rely on fidelity-based witnesses, these are powerless to detect entanglement within a large class of entangled quantum states, the so-called unfaithful states. In this paper, we introduce a highly flexible automated method to construct optimal tests for entanglement detection given a bipartite target state of arbitrary dimension, faithful or unfaithful, and a set of local measurement operators. By restricting the number or complexity of the considered measurement settings, our method outputs the most convenient protocol which can be implemented using a wide range of experimental techniques such as photons, superconducting qudits, cold atoms or trapped ions. With an experimental quantum optics setup that can prepare and measure arbitrary high-dimensional mixed states, we implement some $3$-setting protocols generated by our method. These protocols allow us to experimentally certify 2- and 3-unfaithful entanglement in 4-dimensional photonic states, some of which contain well above 50% of noise.

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arXiv2021

Pathways for entanglement based quantum communication in the face of high noise

Entanglement based quantum communication offers an increased level of security in practical secret shared key distribution. One of the fundamental principles enabling this security -- the fact that interfering with one photon will destroy entanglement and thus be detectable -- is also the greatest obstacle. Random encounters of traveling photons, losses and technical imperfections make noise an inevitable part of any quantum communication scheme, severely limiting distance, key rate and environmental conditions in which QKD can be employed. Using photons entangled in their spatial degree of freedom, we show that the increased noise resistance of high-dimensional entanglement, can indeed be harnessed for practical key distribution schemes. We perform quantum key distribution in eight entangled paths at various levels of environmental noise and show key rates that, even after error correction and privacy amplification, still exceed $1$ bit per photon pair and furthermore certify a secure key at noise levels that would prohibit comparable qubit based schemes from working.

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arXiv2021

Long-distance entanglement purification for quantum communication

High-quality long-distance entanglement is essential for both quantum communication and scalable quantum networks. Entanglement purification is to distill high-quality entanglement from low-quality entanglement in a noisy environment and it plays a key role in quantum repeaters. The previous significant entanglement purification experiments require two pairs of low-quality entangled states and were demonstrated in table-top. Here we propose and report a high-efficiency and long-distance entanglement purification using only one pair of hyperentangled states. We also demonstrate its practical application in entanglement-based quantum key distribution (QKD). One pair of polarization spatial-mode hyperentanglement was distributed over 11 km multicore fiber (noisy channel). After purification, the fidelity of polarization entanglement arises from 0.771 to 0.887 and the effective key rate in entanglement-based QKD increases from 0 to 0.332. The values of Clauser-Horne-Shimony-Holt (CHSH) inequality of polarization entanglement arises from 1.829 to 2.128. Moreover, by using one pair of hyperentanglement and deterministic controlled-NOT gate, the total purification efficiency can be estimated as 6.6x10^3 times than the experiment using two pairs of entangled states with spontaneous parametric down-conversion (SPDC) sources. Our results offer the potential to be implemented as part of a full quantum repeater and large scale quantum network.

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arXiv2020

Experimental high-dimensional quantum teleportation

Quantum teleportation provides a way to transmit unknown quantum states from one location to another. In the quantum world, multilevel systems which enable high-dimensional systems are more prevalent. Therefore, to completely rebuild the quantum states of a single particle remotely, one needs to teleport multilevel (high-dimensional) states. Here, we demonstrate the teleportation of high-dimensional states in a three-dimensional six-photon system. We exploit the spatial mode of a single photon as the high-dimensional system, use two auxiliary entangled photons to realize a deterministic three-dimensional Bell state measurement. The fidelity of teleportation process matrix is F=0.596\pm0.037. Through this process matrix, we can prove that our teleportation is both nonclassical and genuine three dimensional. Our work paves the way to rebuild complex quantum systems remotely and to construct complex quantum networks.

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arXiv2020

Efficient generation of high-dimensional entanglement through multi-path downconversion

High-dimensional entanglement promises to greatly enhance the performance of quantum communication and enable quantum advantages unreachable by qubit entanglement. One of the great challenges, however, is the reliable production, distribution and local certification of high-dimensional sources of entanglement. In this article, we present an optical setup capable of producing quantum states with an exceptionally high-level of scalability, control and quality, that, together with novel certification techniques, achieve the highest amount of entanglement recorded so far. We showcase entanglement in $32$-spatial dimensions with record fidelity to the maximally entangled state ($F=0.933\pm0.001$) and introduce measurement efficient schemes to certify entanglement of formation ($E_{oF}=3.728\pm0.006$). Combined with the existing multi-core fibre technology, our results will lay a solid foundation for the construction of high-dimensional quantum networks.

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arXiv2020

Experimental creation of Multi-Photon High-Dimensional Layered Quantum States

Quantum entanglement is one of the most important resources in quantum information. In recent years, the research of quantum entanglement mainly focused on the increase in the number of entangled qubits or the high-dimensional entanglement of two particles. Compared with qubit states, multipartite high-dimensional entangled states have beneficial properties and are powerful for constructing quantum networks. However, there are few studies on multipartite high-dimensional quantum entanglement due to the difficulty of creating such states. In this paper, we experimentally prepared a multipartite high-dimensional state $|Ψ_{442}\rangle=\frac{1}{2}(|000\rangle+|110\rangle+|221\rangle+|331\rangle)$ by using the path mode of photons. We obtain the fidelity $F=0.854\pm0.007$ of the quantum state, which proves a real multipartite high-dimensional entangled state. Finally, we use this quantum state to demonstrate a layered quantum network in principle. Our work highlights another route towards complex quantum networks.

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