玻色玻璃的热演化与无序依赖性：空间、谱及局域化特征

中文摘要 AI 辅助

在本工作中，我们利用三种互补的诊断手段来表征无序玻色-哈伯德模型中玻色玻璃相的玻璃态特征：有限温度谱函数、空间不均匀性以及逆参与率。通过有限温度格林函数和随机相位近似获得的谱分析表明，无序在莫特能隙内引入了局域化的低能态，并在足够强的无序下最终闭合该能隙。利用古茨威勒变分法计算的空间不均匀性随无序度急剧增加，然后在中等无序强度下趋于饱和。逆参与率通过对小系统进行精确对角化计算得出，它揭示了更强的无序会增强局域化。温度的升高抑制了这些由无序诱导的特征：低能谱权重减小，空间不均匀性变化更加平滑，逆参与率也降低。综合来看，这些诊断表明无序驱动了玻璃态特征的发展，而热涨落则逐渐抹去其标志。空间不均匀性的早期饱和与低能激发及逆参与率的持续演化相比，表明没有任何单一诊断能完全捕捉玻色玻璃态的演化，凸显了联合表征的必要性。

英文摘要

In this work, we characterize the glassy character of the Bose-glass phase in a disordered Bose-Hubbard model using three complementary diagnostics: the finite-temperature spectral function, spatial inhomogeneity, and the inverse participation ratio. Spectral analysis, obtained from finite-temperature Green's function and random phase approximation, shows that disorder introduces localized low-energy states within the Mott gap, eventually closing the gap at sufficiently strong disorder. Spatial inhomogeneity, calculated using the Gutzwiller ansatz, increases sharply with disorder and then saturates at moderate disorder strengths. The inverse participation ratio has been calculated from the exact diagonalization of a small system, and it reveals enhanced localization with stronger disorder. Increasing temperature suppresses these disorder-induced features: the low-energy spectral weight diminishes, the spatial inhomogeneity varies more smoothly, and the IPR decreases. Taken together, these diagnostics show that disorder drives the development of glassy character, while thermal fluctuations gradually wash out its signatures. The early saturation of spatial inhomogeneity compared with the continued evolution of low-energy excitations and the inverse participation ratio demonstrates that no single diagnostic fully captures the evolution of the Bose-glass state, highlighting the need for a combined characterization.

发表机构

• University of Calcutta（加尔各答大学）

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