title: Vibronic origin of long-lived coherence in an artificial molecular light harvester.
abstract: Natural and artificial light-harvesting processes have recently gained new interest. Signatures of long-lasting coherence in spectroscopic signals of biological systems have been repeatedly observed, albeit their origin is a matter of ongoing debate, as it is unclear how the loss of coherence due to interaction with the noisy environments in such systems is averted. Here we report experimental and theoretical verification of coherent exciton-vibrational (vibronic) coupling as the origin of long-lasting coherence in an artificial light harvester, a molecular J-aggregate. In this macroscopically aligned tubular system, polarization-controlled 2D spectroscopy delivers an uncongested and specific optical response as an ideal foundation for an in-depth theoretical description. We derive analytical expressions that show under which general conditions vibronic coupling leads to prolonged excited-state coherence.
authors.affiliation: Institut für Theoretische Physik, Universität Ulm, Albert-Einstein Allee 11, 89069 Ulm, Germany.
authors.forename: James
authors.initials: J
authors.lastname: Lim
authors.affiliation: 1] Department of Chemical Physics, Lund University, PO Box 124, SE-22100 Lund, Sweden [2] Department of Chemical Physics, Charles University in Prague, Ke Karlovu 3, 121 16 Praha 2, Czech Republic.
authors.forename: David
authors.initials: D
authors.lastname: Paleček
authors.affiliation: Institut für Theoretische Physik, Universität Ulm, Albert-Einstein Allee 11, 89069 Ulm, Germany.
authors.forename: Felipe
authors.initials: F
authors.lastname: Caycedo-Soler
authors.affiliation: Photonics Institute, Vienna University of Technology, Gusshausstrasse 27, 1040 Vienna, Austria.
authors.forename: Craig N
authors.initials: CN
authors.lastname: Lincoln
authors.affiliation: Departamento de Física Aplicada, Universidad Politécnica de Cartagena, Cartagena 30202, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Prior
authors.affiliation: Forschungszentrum für Elektronenmikroskopie, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraβe 36a, D-14195 Berlin, Germany.
authors.forename: Hans
authors.initials: H
authors.lastname: von Berlepsch
authors.affiliation: Institut für Theoretische Physik, Universität Ulm, Albert-Einstein Allee 11, 89069 Ulm, Germany.
authors.forename: Susana F
authors.initials: SF
authors.lastname: Huelga
authors.affiliation: Institut für Theoretische Physik, Universität Ulm, Albert-Einstein Allee 11, 89069 Ulm, Germany.
authors.forename: Martin B
authors.initials: MB
authors.lastname: Plenio
authors.affiliation: Department of Chemical Physics, Lund University, PO Box 124, SE-22100 Lund, Sweden.
authors.forename: Donatas
authors.initials: D
authors.lastname: Zigmantas
authors.affiliation: Photonics Institute, Vienna University of Technology, Gusshausstrasse 27, 1040 Vienna, Austria.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Hauer