arXiv subjects

Yu-Cheng Li

Publications and source records attributed to Yu-Cheng Li.

4 recordsLinked to original sources

arXiv2026

Coherence Transfer in Quantum Networks

Detecting coherence transfer in complex quantum networks can be challenging due to uncharacterized experimental conditions and limited system access. Here, we use static and dynamic coherence features to introduce a nonlinear criterion for identifying coherence transfer. The criterion requires only two measurement settings for network-state populations in an experimental state basis, regardless of the network's size. It remains valid even when the verification capabilities of checkpoint nodes are uncharacterized. The principle and method are general, encompassing networks with different access levels and scenarios, from those requiring no input changes to those involving coherence dynamics in the time domain. Experimentally, using remote state preparation and entanglement swapping, we transfer single polarization qubits and polarization-entangled pairs in four- and six-photon entanglement networks. The criterion provides experimental evidence of coherence transfer in multi-photon entanglement networks. Our findings offer a practical tool for coherence transfer in quantum information and open quantum systems in networks.

quant-ph↗

arXiv2024

Quantification of Photon Fusion for Genuine Multiphoton Quantum Correlations

Fusing photon pairs creates an arena where indistinguishability can exist between two two-photon amplitudes contributing to the same joint photodetection event. This two-photon interference has been extensively utilized in creating multiphoton entanglement, from passive to scalable generation, from bulk-optical to chip-scale implementations. While significant, no experimental evidence exists that the full capability of photon fusion can be utterly quantified like a quantum entity. Herein, we demonstrate the first complete capability quantification of experimental photon fusion. Our characterization faithfully measures the whole abilities of photon fusion in the experiment to create and preserve entangled photon pairs. With the created four- and six-photon entangled states using spontaneous parametric down-conversion entanglement sources, we show that capability quantification provides a faithful assessment of interferometry for generating genuine multiphoton entanglement and Einstein-Podolsky-Rosen steering. These results reveal a practical diagnostic method to benchmark photon fusion underlying the primitive operations in general quantum photonics devices and networks.

quant-ph↗

arXiv2023

Scalable Determination of Multipartite Entanglement in Quantum Networks

Quantum networks comprised of entangled end nodes serve stronger than the classical correlation for unparalleled quantum internet applications. However, practical quantum networking is affected by noise, which at its worst, causes end nodes to be described by pre-existing classical data. In such untrusted networks, determining quantum network fidelity and genuine multi-node entanglement becomes crucial. Here, we show that determining quantum network fidelity and genuine $N$-node entanglement in an untrusted star network requires only $N+1$ measurement settings. This method establishes a semi-trusted framework, allowing some nodes to relax their assumptions. Our network determination method is enabled by detecting genuine $N$-node Einstein-Podolsky-Rosen steerability. Experimentally, using spontaneous parametric down-conversion entanglement sources, we demonstrate the determinations of genuine 3-photon and 4-photon quantum networks and the false positives of the widely used entanglement witness, the fidelity criterion of $1/2$. Our results provide a scalable method for the determination of multipartite entanglement in realistic quantum networks.

quant-ph↗

arXiv2021

A Memory-Efficient FM-Index Constructor for Next-Generation Sequencing Applications on FPGAs

FM-index is an efficient data structure for string search and is widely used in next-generation sequencing (NGS) applications such as sequence alignment and de novo assembly. Recently, FM-indexing is even performed down to the read level, raising a demand of an efficient algorithm for FM-index construction. In this work, we propose a hardware-compatible Self-Aided Incremental Indexing (SAII) algorithm and its hardware architecture. This novel algorithm builds FM-index with no memory overhead, and the hardware system for realizing the algorithm can be very compact. Parallel architecture and a special prefetch controller is designed to enhance computational efficiency. An SAII-based FM-index constructor is implemented on an Altera Stratix V FPGA board. The presented constructor can support DNA sequences of sizes up to 131,072-bp, which is enough for small-scale references and reads obtained from current major platforms. Because the proposed constructor needs very few hardware resource, it can be easily integrated into different hardware accelerators designed for FM-index-based applications.

cs.AR↗