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Continuous-time quantum walk on an extended star graph: Disorder-enhanced trapping process
Saad Yalouz1, Vincent Pouthier1
1Institut UTINAM, Université de Franche-Comté, CNRS UMR 6213, 25030 Besançon Cedex, France.
Physical Review. E
|February 20, 2020
Summary
Disorder in star graphs significantly enhances exciton absorption, leading to complete trapping. An optimal disorder level minimizes absorption time by restructuring exciton states, creating a superoptimized process.
Area of Science:
- Condensed matter physics
- Quantum mechanics
- Materials science
Background:
- Exciton dynamics are crucial for energy transfer in materials.
- Disorder in complex networks can significantly alter quantum phenomena.
- Star graphs provide a model for studying energy transport in branched structures.
Purpose of the Study:
- To investigate exciton dynamics on a disordered star graph with an energy-trapping central site.
- To compare the effects of disorder versus an ordered network on exciton absorption.
- To identify optimal conditions for minimizing exciton absorption time.
Main Methods:
- Utilizing a tight-binding model to simulate exciton behavior.
- Analyzing exciton dynamics on an extended star graph with a central trap.
- Comparing results from disordered and ordered network configurations.
Main Results:
- Disorder drastically improves and completes excitonic absorption compared to ordered networks.
- An optimal level of disorder is found to minimize absorption time due to exciton eigenstate restructuring.
- An optimal absorption rate further reduces trapping time, leading to a superoptimized process.
Conclusions:
- Disorder plays a critical role in enhancing and accelerating exciton trapping in star graphs.
- The interplay between disorder and superradiance transitions optimizes the energy trapping process.
- These findings have implications for designing efficient light-harvesting systems.
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