Coherent exciton transport and trapping on long-range interacting cycles
X. P. Xu · Physical Review E · 2009
We consider coherent exciton transport modeled by continuous-time quantum walks 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) approximately t;{-0.5} and pi(t) approximately t;{-1} , respectively. However, for large values of m , the classical and quantum efficiency scales as p(t) approximately t;{-1} and pi(t) approximately t;{-2} . We give a theoretical explanation of this transition using the method of stationary phase approximation. In the long time limit, depending on the network size N and parameter m , the limiting probability distributions of quantum transport show various patterns. When the network size N is an even number, we find an asymmetric transition probability of quantum transport between the initial node and its opposite node. This asymmetry depends on the precise values of N and m . Finally, we study the transport processes in the presence of traps and find that the survival probability decays faster on networks of large m .