arXiv subjects

Maohua Wang

Publications and source records attributed to Maohua Wang.

3 recordsLinked to original sources

arXiv2026

Non-Markovian giant-atom dynamics in a disordered lattice

While ideal lattice models have been widely used to study giant-atom systems, fabrication-induced defects inevitably introduce disorder in realistic platforms. Here, we study non-Markovian dynamics of a giant atom coupled to a discrete photonic lattice with on-site frequency disorder. Using time-domain and spectral analyses, we show that the overall population-decay envelope and global photon-transport patterns remain robust against moderate lattice disorder, while the quantified non-Markovian memory can be significantly enhanced within the explored disorder range. We characterize the memory using a normalized geometrical non-Markovianity measure tailored to delayed giant-atom feedback and demonstrate how the coupling-point separation and the disorder strength serve as complementary parameters that shape the delay timescale and the complexity of coherent-feedback interference. Spectral analysis reveals that scattering-band transport is relatively insensitive to disorder, whereas disorder-sensitive bound-state branches and localization features reshape revival windows and promote information backflow. Our results establish a disorder-aware framework for understanding and engineering non-Markovian feedback effects of giant atoms in structured reservoirs.

quant-ph↗

arXiv2023

Unidirectional Photonic Reflector Using a Defective Atomic Lattice

Based on the broken spatial symmetry, we propose a novel scheme for engineering a unidirectional photonic reflector using a one-dimensional atomic lattice with defective cells that have been specifically designed to be vacant. By trapping three-level atoms and driving them into the regime of electromagnetically induced transparency, and through the skillful design of the number and position of vacant cells in the lattice, numerical simulations demonstrate that a broad and high unidirectional reflection region can be realized within EIT window. This proposed unidirectional reflector scheme provides a new platform for achieving optical nonreciprocity and has potential applications for designing optical circuits and devices of nonreciprocity at extremely low energy levels.

physics.optics↗

arXiv2020

Improving Chinese Segmentation-free Word Embedding With Unsupervised Association Measure

Recent work on segmentation-free word embedding(sembei) developed a new pipeline of word embedding for unsegmentated language while avoiding segmentation as a preprocessing step. However, too many noisy n-grams existing in the embedding vocabulary that do not have strong association strength between characters would limit the quality of learned word embedding. To deal with this problem, a new version of segmentation-free word embedding model is proposed by collecting n-grams vocabulary via a novel unsupervised association measure called pointwise association with times information(PATI). Comparing with the commonly used n-gram filtering method like frequency used in sembei and pointwise mutual information(PMI), the proposed method leverages more latent information from the corpus and thus is able to collect more valid n-grams that have stronger cohesion as embedding targets in unsegmented language data, such as Chinese texts. Further experiments on Chinese SNS data show that the proposed model improves performance of word embedding in downstream tasks.

cs.CL↗