Xingdong Zhao

We propose a physical scheme to realize a parity-time (PT)-symmetric triple-well potential in a coherent atomic gas and investigate the emergence of higher-order exceptional points (EPs). Through careful parameter tuning, we successfully identify a third-order EP (EP3), observing its characteristic cube-root response to perturbations—a key signature distinguishing it from second-order EPs (EP2). Notably, EP3 exhibits significantly enhanced sensitivity, underscoring its potential for advancing quantum information technologies. Furthermore, we show that the imaginary part of the nonlinear PT potential critically governs PT phase transitions and dynamically reshapes the phase diagram. Our system also supports stable optical solitons, whose properties can be precisely controlled by tuning the interplay between linear and nonlinear PT potentials. When these potentials act as defects, soliton scattering displays strongly asymmetric behavior, directly adjustable via the potentials’ imaginary components. These findings open new avenues for applications in optical switch, optical sensing, and high-precision information transmission.

In this paper, we consider the problem of calculating the ground state of a 3D pure dipolar Bose-Einstein condensate in a double-well potential described by the nonlocally anisotropic Gross-Pitaevskii equation. Building upon our previously proposed projected-infeasible augmented Lagrangian gradient method (J. Comput. Appl. Math., 475, 117040, 2026), this paper extends the algorithm to handle long-range anisotropic dipole-dipole convolution interactions and proves its global convergence in the lim inf sense. Numerical tests are performed to verify its reliability and reveal the ground state phase transition characteristics of dipolar condensates.

耗散孤子是一种在外部驱动与损耗平衡、非线性与衍射效应平衡共同作用下形成的局域化波包，在频率梳产生及精密光场调控中扮演着重要角色。针对腔内耗散孤子的调控研究，现有工作多集中于腔内填充局域非线性介质的系统，而对非局域非线性效应下腔内孤子的形成机制及调控手段尚缺乏讨论与探索。本文基于高斯泵浦驱动的非局域腔内光动力学方程，考察了不同非局域响应下腔内耗散孤子的演化行为以及失谐扫描下的光场动力学特征。理论与数值结果表明，以高斯光场作为初始态和泵浦，初始光场在弱非局域非线性效应下可演化为多孤子态；而在强非局域作用下，系统最终形成的终态则是单孤子结构。该现象可通过不同非局域宽度下系统中存在不同的非线性稳态模式进行解释。同时发现，在非局域响应效应的作用下，正、负向失谐扫描会导致腔内光场产生不同的峰数演化和混沌态分布区域。本文的研究结果揭示了非局域非线性效应对腔内耗散孤子动力学行为的影响规律，为理解非局域非线性腔内耗散孤子的形成及其动力学调控提供了新的机制与手段。

多态量子逻辑门为提高信息编码维度和增强光场调控能力提供了新思路。我们提出通过复合孤子叠加实现三态量子泡利(Pauli)门的方案。本文考虑倒Ψ型五能级冷原子系统，利用奇异微扰展开法推导出三分量耦合非线性薛定谔(nonlinear Schrödinger,NLS)方程。量子态的单个量子比特由NLS方程的精确复合孤子解的分量定义。通过适当的旋转操作，在单个量子比特上实现Pauli-X、Pauli-Y和Pauli-Z操作。进一步以暗-亮-亮型三分量复合孤子作为单个量子比特，分析其自由传播及门操作。结果表明，Pauli-X门可实现分量间交换，Pauli-Y门在分量交换过程中引入相位调制，Pauli-Z门实现相位翻转。本文利用三分量复合孤子叠加态实现三态逻辑操作，为多态量子逻辑门和多通道光信息处理提供了新方案。

Topological bound states in the continuum (TBICs) are localized boundary states spectrally embedded in extended-mode continua and robust against weak symmetry-preserving perturbations. Sub-symmetry (SubSy) can protect these states even when global chiral symmetry is broken. Here, we propose a modified bilayer Su–Schrieffer–Heeger (SSH) photonic lattice with uniform sublattice detuning that preserves interlayer mirror symmetry and supports two complementary energy-referenced SubSy conditions. This enables selective control of multiple topological boundary states with distinct sublattice character, which can be shifted between band gaps and bulk continua without hybridization. Periodic longitudinal modulation enables transitions between in-gap Floquet edge states and Floquet TBICs. Compared with the standard bilayer SSH lattice, the detuned system maintains strongly localized Floquet boundary states over a broader driving range.

Soliton self-frequency shift (SSFS) in nonlinear optical fibers is a powerful mechanism for broadband and tunable wavelength conversion. Nevertheless, achieving flexible and efficient control over the resulting Raman solitons remains challenging. Here, we numerically and experimentally demonstrate controlled frequency tuning of Raman solitons using Pearcey–Gaussian (PG) pulses in optical fibers. By tailoring the temporal asymmetry profile and spectral phase modulation of the PG pulse, the driven SSFS provides flexible control of Raman soliton dynamics. We show that a secondary Raman soliton can be efficiently excited not only by a tail-trailing PG pulse, but also by an initially tail-leading PG pulse with an appropriate quadratic spectral chirp. Moreover, introducing this chirp yields a larger and more tunable frequency shift than in the unchirped case, providing precise control over the spectral positions of multiple Raman solitons. Compared with asymmetric Airy-pulse excitation, the PG-based approach offers distinct advantages in both multiple Raman soliton generation and frequency tuning performance. Our results establish PG pulses as a powerful tool for engineering SSFS-driven frequency conversion and are expected to inspire new strategies for soliton control using other classes of structured optical pulses.

We demonstrate that a nonlinear spin–orbit interaction (SOI) emerges in cold Rydberg atomic gases, where the orbital characteristics (spatial structure) of light fields become coupled to their polarization (spin). This SOI originates from the giant, spatially inhomogeneous nonlinear optical response arising from the strong, long-range interactions between Rydberg atoms. By extending the theoretical framework beyond the conventional paraxial approximation, we derive a light propagation equation that rigorously incorporates such inhomogeneous nonlinearity. Our study reveals that the SOI is driven by the gradient of the inhomogeneous nonlinear response and therefore vanishes in linear or homogeneous media. When two orthogonal light fields co-propagate, the SOI generates novel nonlinear energy transfer and pronounced structural deformation, which are not captured without considering the SOI or within the paraxial approximation. Furthermore, owing to its direct dependence on the gradient of the nonlocal nonlinearity, the SOI is inherently mode-dependent. As a consequence, the structural deformation becomes particularly significant for light fields with odd parity symmetry. Our investigation establishes novel pathways for exploring the nonlinear SOI and examining inhomogeneous nonlinear optical responses beyond the paraxial approximation in cold Rydberg atomic gases.