分类： 心理学 >> 应用心理学 提交时间： 2019-09-18
摘要： Age-related differences in affective meanings of words are widely used by researchers studying emotions, word recognition, attention, memory and text -based sentiment analysis. However, no Chinese affective norms for older adults are available. This article firstly presents the available large-scale Chinese affective norms for 2, 061 4-character words rated in labs by 114 older and 150 younger adults (CAN4Age) who evaluated these words on four dimensions: valence, arousal, dominance, and familiarity. We also compiled 4 lexical variables for each word, including word frequency, word complexity, character frequency and character complexity. In general, older adults tend to evaluate emotional words more extremely than younger adults do. That is, they rate positive words as more positive and negative words as more negative than younger adults do. Specifically, older adults tend to perceive positive words as more arousing and less controllable and negative words as less arousing and more controllable than that of younger adults. This age-related database will enable researchers to study how emotional characteristics of words influence their cognitive processing, and how this influence evolves with age in Chinese. This age-related difference study on affective norms not only provides insights to cognitive neuroscience, gerontology and psychology in experimental studies, but the produced affective word collection also has great value as a resource for affective analysis in natural language processing applications. These norms can be downloaded as supplemental materials with this published article.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Bound states of solitons, alias soliton molecules (SMs), are well known in one-dimensional (1D) systems, while making stable bound states of multidimensional solitons is a challenging problem because of the underlying instabilities. Here we propose a scheme for the creation of stable (2+1)D and (3+1)D optical SMs in a gas of cold Rydberg atoms, in which electromagnetically induced transparency (EIT) is induced by a control laser field. We show that, through the interplay of the EIT and the strong long-range interaction between the Rydberg atoms, the system gives rise to giant nonlocal Kerr nonlinearity, which in turn supports stable (2+1)D spatial optical SMs, as well as ring-shaped soliton necklaces, including rotating ones. They feature a large size, low generation power, and can be efficiently manipulated by tuning the nonlocality degree of the Kerr nonlinearity. Stable (3+1)D spatiotemporal optical SMs, composed of fundamental or vortex solitons, with low power and ultraslow propagation velocity, can also be generated in the system. These SMs can be stored and retrieved through the switching off and on of the control laser field. The findings reported here suggest applications to data processing and transmission in optical systems.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： We propose a scheme for the creation of stable optical Ferris wheel(OFW) solitons in a nonlocal Rydberg electromagnetically induced transparency(EIT) medium. Depending on a careful optimization to both the atomic density and the one-photon detuning, we obtain an appropriate nonlocal potential provided by the strong interatomic interaction in Rydberg states which can perfectly compensate for the diffraction of the probe OFW field. Numerical results show that the fidelity keeps larger than 0.96 while the propagation distance has exceeded 160 diffraction lengths. Higher-order OFW solitons with arbitrary winding numbers are also discussed. Our study provides a straightforward route to generate spatial optical solitons in the nonlocal response region of cold Rydberg gases.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
Yingying Zhang
Shiqiang Xia
Xingdong Zhao
Lu Qin
Xuejing Feng
Wenrong Qi
Yajing Jiang
Hai Lu
Daohong Song
Liqin Tang
Zunlue Zhu
Yufang Liu
摘要： Higher-order exceptional points (EPs), which appear as multifold degeneracies in the spectra of non-Hermitian systems, are garnering extensive attention in various multidisciplinary fields. However, constructing higher-order EPs still remains as a challenge due to the strict requirement of the system symmetries. Here we demonstrate that higher-order EPs can be judiciously fabricated in PT -symmetric staggered rhombic lattices by introducing not only on-site gain/loss but also nonHermitian couplings. Zero-energy flatbands persist and symmetry-protected third-order EPs (EP3) arise in these systems owing to the non-Hermitian chiral/sublattice symmetry, but distinct phase transitions and propagation dynamics occur. Specifically, the EP3 arises at the Brillouin zone (BZ) boundary in the presence of on-site gain/loss. The single-site excitations display an exponential power increase in the PT -broken phase. Meanwhile, a nearly flatband sustains when a small lattice perturbation is applied. For the lattices with non-Hermitian couplings, however, the EP3 appears at the BZ center. Quite remarkably, our analysis unveils a dynamical delocalization-localization transition for the excitation of the dispersive bands and a quartic power increase beyond the EP3. Our scheme provides a new platform towards the investigation of the higher-order EPs, and can be further extended to the study of topological phase transitions or nonlinear processes associated with higher-order EPs.
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