质量各向异性驱动的极子凝聚体中的条纹图案形成与方向调制不稳定性
Mass-anisotropy driven stripe pattern formation and directional modulational instability in polariton condensate
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中文总结 AI 辅助
该研究探究质量各向异性对受驱动耗散型极子凝聚体的影响，通过Bogoliubov分析揭示其可控制调制不稳定性与条纹图案形成，确定质量各向异性为关键控制参数。
中文摘要 AI 辅助
受近期在有效质量电控制及各向异性质量分布实现方面实验进展的推动，我们研究了质量各向异性对受驱动耗散型极子凝聚体的影响，重点关注调制不稳定性、图案形成以及涌现图案的集体动力学。我们证明，在非共振高斯激光束泵浦的激子-极子凝聚体中，当质量比超过临界值时，沿两个正交方向的不等效有效质量会诱导条纹图案形成。对均匀泵浦系统的Bogoliubov分析表明，质量各向异性不会改变调制不稳定性判据，但会通过随质量比增大而减小较大有效质量方向上的最不稳定波长，重塑不稳定模式的色散，这为图案选择引入了各向异性控制的长度尺度。当泵浦宽度与最不稳定波长相当时，凝聚体发生调制不稳定性，沿较大有效质量方向形成条纹图案，同时伴随同一方向上的粒子数涨落和质心振荡。随着泵浦宽度进一步增大，条纹在时间演化过程中发生扭曲并出现空间不规则性，表现出调制不稳定性。不过，与各向同性质量情形下观察到的完全无序图案不同，各向异性质量分布保留了显著的方向偏好。我们的结果确定，质量各向异性是非平衡极子凝聚体中方向调制不稳定性和图案形成的关键控制参数。
英文摘要
Motivated by recent experimental advances toward electrical control of the effective mass and the realization of anisotropic mass distributions, we investigate the impact of mass anisotropy on driven-dissipative polariton condensates, focusing on modulational instability, pattern formation, and the collective dynamics of the emergent patterns. We show that unequal effective masses along the two orthogonal directions induce stripe pattern formation in an exciton-polariton condensate pumped by a non-resonant Gaussian laser beam above a critical mass ratio. A Bogoliubov analysis of the homogeneously pumped system reveals that mass anisotropy leaves the modulational-instability criteria unchanged but reshapes the unstable-mode dispersion by reducing the most unstable wave- length along the direction of larger effective mass with increasing mass ratio. This introduces an anisotropy-controlled length scale for pattern selection. When the pump width becomes comparable to the most unstable wavelength, the condensate becomes modulationally unstable and develops stripe patterns along the direction of larger effective mass, accompanied by particle-number fluctua- tions and center-of-mass oscillations along the same direction. As the pump width increases further, the stripes become distorted and develop spatial irregularities during the time evolution, indicative of modulational instability. Nevertheless, the anisotropic mass distribution preserves a pronounced directional preference, in contrast to the fully disordered patterns observed in the isotropic-mass case. Our results identify mass anisotropy as a key control parameter for directional modulational instability and pattern formation in nonequilibrium polariton condensates.
