title: Origin of long-lived quantum coherence and excitation dynamics in pigment-protein complexes.
abstract: We explore the mechanism for the long-lived quantum coherence by considering the discrete phonon modes: these vibrational modes effectively weaken the exciton-environment interaction, due to the new composite (polaron) formed by excitons and vibrons. This subsequently demonstrates the role of vibrational coherence which greatly contributes to long-lived feature of the excitonic coherence that has been observed in femtosecond experiments. The estimation of the timescale of coherence elongated by vibrational modes is given in an analytical manner. To test the validity of our theory, we study the pigment-protein complex in detail by exploring the energy transfer and coherence dynamics. The ground-state vibrational coherence generated by incoherent radiations is shown to be long-survived and is demonstrated to be significant in promoting the excitation energy transfer. This is attributed to the nonequilibriumness of the system caused by the detailed-balance-breaking, which funnels the downhill migration of excitons.
authors.affiliation: Department of Physics and Astronomy, SUNY Stony Brook, Stony Brook, NY 11794, USA.|Department of Chemistry, University of California Irvine, Irvine, CA 92697, USA.
authors.forename: Zhedong
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Physics and Astronomy, SUNY Stony Brook, Stony Brook, NY 11794, USA.|Department of Chemistry, SUNY Stony Brook, Stony Brook, NY 11794, USA.|State Key Laboratory of Electroanalytical Chemistry, Changchun Institute for Applied Chemistry, Chinese, Academy of Sciences, Changchun, Jilin 130022, P. R. China.
authors.forename: Jin
authors.initials: J
authors.lastname: Wang
mesh_terms: D004735:Energy Transfer; D008962:Models, Theoretical; D060739:Phonons; D010860:Pigments, Biological / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D011789:Quantum Theory; D014732:Vibration
chemical_list: D010860:Pigments, Biological; D011506:Proteins