Trapped-Ion Quantum Simulation of Multimode Electron Transfer Models with an Engineered Reservoir*

Electron transfer (ET) is a fundamental process that describes the relocation of an electron within or across physical, chemical, and biological systems. This mechanism plays a crucial role in chemical and biological reactions ranging from redox catalysis to photosynthesis. The minimal model of ET with one environmentally damped vibrational mode has been experimentally studied in [1] using a trapped-ion quantum simulator, which allows for precise control over the system parameters, giving access to different regimes of adiabaticity and optimal transfer. In this work, we investigate the ET model with two environmentally damped vibrational modes in the strong electronic coupling regime, where we assign the fast and slow vibrational modes to the local molecular and solvent modes of a biochemical system, respectively. We observe that the transfer rates are enhanced when the two vibrational modes have the same energy. Conversely, when the solvent mode is set to have a lower frequency than the molecular mode, it enables additional transfer pathways, making the process more robust. This finding provides insights into the multimode ET behaviors, which may lead to the design and development of efficient bioenergetics and molecular electronics.

[1] Visal So et al., Sci. Adv. 10, eads8011 (2024)