title: Non-Hermitian exciton dynamics in a photosynthetic unit system.
abstract: The non-Hermitian quantum dynamics of excitonic energy transfer in photosynthetic systems is investigated using a dissipative two-level dimer model. The approach is based on Green's function formalism which permits consideration of decoherence and intersite transfer processes on comparable terms. The results indicate a combination of coherent and incoherent behavior at higher temperatures with the possibility of exceptional points occurring at the coherent-incoherent crossover regime at critical temperatures. When each dimer site is coupled equally to the environmental sources of dissipation, the excitonic wavepacket evolves with time with a coherent component, which can be attributed to the indistinguishability of the sources of dissipation. The time evolution characteristics of the B850 Bchls dimer system is analysed using typical parameter estimates in photosynthetic systems, and the quantum brachistochrone passage times are obtained for a range of parameters.
authors.affiliation: Minerals and Materials Science and Technology, Mawson Institute, Division of ITEE, University of South Australia, Adelaide, South Australia 5095, Australia. thilaphys@gmail.com
authors.forename: A
authors.initials: A
authors.lastname: Thilagam
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D019414:Chlorobi / Q000737:chemistry*; D004735:Energy Transfer; D008954:Models, Biological; D010788:Photosynthesis; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D055503:Protein Multimerization; D011789:Quantum Theory; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D045322:Photosynthetic Reaction Center Complex Proteins