arXiv subjects

Lirong Chen

Publications and source records attributed to Lirong Chen.

6 recordsLinked to original sources

arXiv2025

Topic mining based on fine-tuning Sentence-BERT and LDA

Research background: With the continuous development of society, consumers pay more attention to the key information of product fine-grained attributes when shopping. Research purposes: This study will fine tune the Sentence-BERT word embedding model and LDA model, mine the subject characteristics in online reviews of goods, and show consumers the details of various aspects of goods. Research methods: First, the Sentence-BERT model was fine tuned in the field of e-commerce online reviews, and the online review text was converted into a word vector set with richer semantic information; Secondly, the vectorized word set is input into the LDA model for topic feature extraction; Finally, focus on the key functions of the product through keyword analysis under the theme. Results: This study compared this model with other word embedding models and LDA models, and compared it with common topic extraction methods. The theme consistency of this model is 0.5 higher than that of other models, which improves the accuracy of theme extraction

cs.CL↗

arXiv2025

Bright squeezed light in the kilohertz frequency band

The largely technical noise of a free running laser is the fundamental limit for preparation of a bright squeezed light, especially within MHz band. We construct a universal and complete theoretical model for nonclassical stabilization, and propose a novel bright squeezed light generation scheme with assistance of a hybrid noise stabilization technology. The scheme assimilates a broadband passive noise stabilization to successfully extend the feedback frequency bandwidth of a nonclassical active stabilization to MHz band. Meanwhile, the technical noise suppression magnitude is further improved by 9 dB, which creates the prerequisite conditions for preparing a broadband bright squeezed light. Finally, a -5.5 dB bright squeezed light with a power of 1 mW and a squeezing bandwidth among kHz to MHz band was generated. The experimental results agree well with the theoretical one. To the best of our knowledge, it is the first demonstration of a milliwatt-order bright squeezed light across the kHz frequency band. The demonstration sheds light on potential applications of bright squeezed light in quantum metrology and might enable new concepts in the future.

quant-ph↗

arXiv2017

Spatial multiplexing of atom-photon entanglement sources using feed-forward controls and switching networks

The light-matter quantum interface that can create quantum-correlations or entanglement between a photon and one atomic collective excitation is a fundamental building block for a quantum repeater. The intrinsic limit is that the probability of preparing such non-classical atom-photon correlations has to be kept low in order to suppress multi-excitation. To enhance this probability without introducing multi-excitation errors, a promising scheme is to apply multimode memories into the interface. Significant progresses have been made in temporal, spectral, and spatial multiplexing memories, but the enhanced probability for generating the entangled atom-photon pair has not been experimentally realized. Here, by using 6 spin-wave-photon entanglement sources, a switching network and feed-forward control, we build a multiplexed light-matter interface and then demonstrate a ~6-fold (~4-fold) probability increase in generating entangled atom-photon (photon-photon) pairs. The measured compositive Bell parameter for the multiplexed interface is 2.49+-0.03 combined with a memory lifetime of up to ~60 microseconds.

quant-ph↗

arXiv2016

Controllably releasing long-lived quantum memory for photonic polarization qubit into multiple separate photonic channels

We report an experiment in which long-lived quantum memories for photonic polarization qubits (PPQs) are controllably released into any one of multiple separate channels. The PPQs are implemented with an arbitrarily-polarized coherent signal light pulses at the single-photon level and are stored in cold atoms by means of electromagnetic-induced-transparency scheme. Reading laser pulses propagating along the direction at a small angle relative to quantum axis are applied to release the stored PPQs into an output channel. By changing the propagating directions of the read laser beam, we controllably release the retrieved PPQs into 7 different photonic output channels, respectively. At one of the output channels, the measured maximum quantum-process fidelity for the PPQs is 94.2% at storage time of t= 0.85ms. At storage time of 6 ms, the quantum-process fidelity is still beyond 78%, the threshold for the violation of the Bell inequality. The demonstrated controllable release of the stored PPQs may extend the capabilities of the quantum information storage technique.

quant-ph↗

arXiv2015

Simultaneous generation of two spin-wave-photon entangled states in an atomic ensemble

The generation and storage of entangled photons play important roles in quantum information technique. Spontaneous Raman scattering (SRS) in atomic ensembles provides a promising method to generate entangled photons capable of storage. In the past experiments, a spin-wave-photon entangled state is produced via SRS in an atomic ensemble, with which a pair of entangled photons is obtained. Here, we report a scheme of simultaneously generating two spin-wave-photon entangled states in an atomic ensemble by collecting Stokes photons at two different directions. Based on the obtained two atom-photon entangled sources, we generate a three-photon GHZ polarization-entangled state and conditionally prepare a polarization-entangled photon pair, respectively.

quant-ph↗

arXiv2013

Long lifetime and high-fidelity quantum memory of photonic polarization qubit by lifting Zeeman degeneracy

Long-lived and high-fidelity memory for photonic polarization qubit (PPQ) is crucial for constructing quantum networks. Here we present an EIT-based millisecond storage system in which a moderate magnetic field is applied on a cold-atom cloud to lift Zeeman degeneracy. PPQ states are stored as two magnetic-field-insensitive spin waves. Especially, the influence of magnetic-field-sensitive spin waves on the storage performances is almost totally avoided. The measured average fidelities of polarization states are 98.6% at 200 us and 78.4% at 4.5 ms, respectively.

physics.atom-ph↗