Coherent Exciton Dynamics and Trapping in Topologically Disordered Systems

光诱导的振动激子量子自囚现象研究

Light-Induced Quantum Self-Trapping of Vibrational Excitons in an Optical Cavity

本文研究了光学腔中光-物质耦合对振动激子能量局域化的影响，揭示了非线性相互作用引发的量子自囚现象，发现光腔可增强传输并稳定能量局域化。

Coherent exciton transport and trapping on long-range interacting cycles

We consider coherent exciton transport modeled by continuous-time quantum walks (CTQWs) on long-range interacting cycles (LRICs), which are constructed by connecting all the two nodes of distance $m$ in the cycle graph. LRIC has a symmetric structure and can be regarded as the extensions of the cycle graph (nearest-neighboring lattice). For small values of $m$, the classical and quantum return probabilities show power law behavior $p(t)\sim t^{-0.5}$ and $π(t)\sim t^{-1}$, respectively. However, for large values of $m$, the classical and quantum efficiency scales as $p(t)\sim t^{-1}$ and $π(t)…

偶极莫尔激子的玻色离域化

Bosonic Delocalization of Dipolar Moiré Excitons

本文发展了外势中相互作用激子的微观理论，揭示莫尔激子间相互作用导致中等密度下的离域化，并可由扭转角和温度调控，为控制莫尔材料能量输运提供新途径。

光合作用能量传递中相干性和非局域性的时域作用：基于扩展的激子模型

Time-resolved role of coherence and delocalization in photosynthetic energy transfer from an extended exciton model

本文基于扩展的激子模型，研究光合作用中相干性和非局域性的时间依赖性作用，揭示内部电子结构与量子传输性能的微观联系。

Generic Mechanism of Optimal Energy Transfer Efficiency: A Scaling Theory of the Mean First Passage Time in Exciton Systems

An asymptotic scaling theory is presented using the conceptual basis of trapping-free subspace (i.e., orthogonal subspace) to establish the generic mechanism of optimal efficiency of excitation energy transfer (EET) in light-harvesting systems. Analogous to Kramers' turnover in classical rate theory, the enhanced efficiency in the weak damping limit and the suppressed efficiency in the strong damping limit define two asymptotic scaling regimes, which are interpolated to predict the functional form of optimal efficiency of the trapping-free subspace. In the presence of static disorder, the scal…

Trapping of Continuous-Time Quantum walks on Erdos-Renyi graphs

We consider the coherent exciton transport, modeled by continuous-time quantum walks, on Erdös-Rény graphs in the presence of a random distribution of traps. The role of trap concentration and of the substrate dilution is deepened showing that, at long times and for intermediate degree of dilution, the survival probability typically decays exponentially with a (average) decay rate which depends non monotonically on the graph connectivity; when the degree of dilution is either very low or very high, stationary states, not affected by traps, get more likely giving rise to a survival probability …

Coherent Population Trapping of Electron Spins in a Semiconductor

In high-purity n-type GaAs under strong magnetic field, we are able to isolate a lambda system composed of two Zeeman states of neutral-donor bound electrons and the lowest Zeeman state of bound excitons. When the two-photon detuning of this system is zero, we observe a pronounced dip in the excited-state photoluminescence indicating the creation of the coherent population-trapped state. Our data are consistent with a steady-state three-level density-matrix model. The observation of coherent population trapping in GaAs indicates that this and similar semiconductor systems could be used for var…

一维Dexter型激子拓扑相变

One-dimensional Dexter-type excitonic topological phase transition

该研究针对一维激子拓扑性质研究不足的问题，计算了一维二聚化激子模型的Zak相位，提出复合手性格点概念解释相关结果，证实拓扑边缘态，首次发现Dexter电子交换过程辅助的拓扑相变。