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Title: Engineering Vibrationally Assisted Energy Transfer in a Trapped-Ion Quantum Simulator

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Journal Article: Published Article
Journal Name:
Physical Review X
Additional Journal Information:
Journal Volume: 8; Journal Issue: 1; Related Information: CHORUS Timestamp: 2018-03-07 10:03:58; Journal ID: ISSN 2160-3308
American Physical Society
Country of Publication:
United States

Citation Formats

Gorman, Dylan J., Hemmerling, Boerge, Megidish, Eli, Moeller, Soenke A., Schindler, Philipp, Sarovar, Mohan, and Haeffner, Hartmut. Engineering Vibrationally Assisted Energy Transfer in a Trapped-Ion Quantum Simulator. United States: N. p., 2018. Web. doi:10.1103/PhysRevX.8.011038.
Gorman, Dylan J., Hemmerling, Boerge, Megidish, Eli, Moeller, Soenke A., Schindler, Philipp, Sarovar, Mohan, & Haeffner, Hartmut. Engineering Vibrationally Assisted Energy Transfer in a Trapped-Ion Quantum Simulator. United States. doi:10.1103/PhysRevX.8.011038.
Gorman, Dylan J., Hemmerling, Boerge, Megidish, Eli, Moeller, Soenke A., Schindler, Philipp, Sarovar, Mohan, and Haeffner, Hartmut. 2018. "Engineering Vibrationally Assisted Energy Transfer in a Trapped-Ion Quantum Simulator". United States. doi:10.1103/PhysRevX.8.011038.
title = {Engineering Vibrationally Assisted Energy Transfer in a Trapped-Ion Quantum Simulator},
author = {Gorman, Dylan J. and Hemmerling, Boerge and Megidish, Eli and Moeller, Soenke A. and Schindler, Philipp and Sarovar, Mohan and Haeffner, Hartmut},
abstractNote = {},
doi = {10.1103/PhysRevX.8.011038},
journal = {Physical Review X},
number = 1,
volume = 8,
place = {United States},
year = 2018,
month = 3

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevX.8.011038

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  • An energy transfer probability distribution function, P(E,E), for the collisional relaxation of a highly vibrationally excited donor molecule (C{sub 6}F{sub 6}, pyrazine) is constructed for the first time from experimental data on the bath (CO{sub 2}) energy gain. A prescription for mapping bath quantum state resolved data onto P(E,E) is described in detail. Analysis of earlier experimental data allows a calculation of the high {Delta}E=E{minus}E region ({minus}7000 cm{sup {minus}1}{lt}E{minus}E{lt}{minus}1500 cm{sup {minus}1}) of P(E,E) for the above systems. Comparison of the P(E,E) functions reveals that C{sub 6}F{sub 6} is a more efficient donor molecule than pyrazine, in agreement with previous experimentsmore » and trajectory calculations. In addition, resonance like structures in the P(E,E) functions arising from long range force mediated, V{endash}V excitation of the carbon dioxide {nu}{sub 3} mode are discussed. These results indicate that accurate P(E,E) functions can be determined from experiments involving probes of the bath energy gain. This technique can be expected to provide stringent tests of current energy transfer theory and can, in principle, be used in conjunction with measurements of thermal kinetics to obtain energy dependent unimolecular rate constants, k{sub E}. {copyright} {ital 1997 American Institute of Physics.}« less
  • Energy transfer within photosynthetic systems can display quantum effects such as delocalized excitonic transport. Recently, direct evidence of long-lived coherence has been experimentally demonstrated for the dynamics of the Fenna-Matthews-Olson (FMO) protein complex [Engel et al., Nature (London) 446, 782 (2007)]. However, the relevance of quantum dynamical processes to the exciton transfer efficiency is to a large extent unknown. Here, we develop a theoretical framework for studying the role of quantum interference effects in energy transfer dynamics of molecular arrays interacting with a thermal bath within the Lindblad formalism. To this end, we generalize continuous-time quantum walks to nonunitary andmore » temperature-dependent dynamics in Liouville space derived from a microscopic Hamiltonian. Different physical effects of coherence and decoherence processes are explored via a universal measure for the energy transfer efficiency and its susceptibility. In particular, we demonstrate that for the FMO complex, an effective interplay between the free Hamiltonian evolution and the thermal fluctuations in the environment leads to a substantial increase in energy transfer efficiency from about 70% to 99%.« less
  • Collisional energy transfer between vibrational ground state CO{sub 2} and highly vibrationally excited monofluorobenzene (MFB) was studied using narrow bandwidth (0.0003 cm{sup −1}) IR diode laser absorption spectroscopy. Highly vibrationally excited MFB with E′ = ∼41 000 cm{sup −1} was prepared by 248 nm UV excitation followed by rapid radiationless internal conversion to the electronic ground state (S{sub 1}→S{sub 0}*). The amount of vibrational energy transferred from hot MFB into rotations and translations of CO{sub 2} via collisions was measured by probing the scattered CO{sub 2} using the IR diode laser. The absolute state specific energy transfer rate constants and scatteringmore » probabilities for single collisions between hot MFB and CO{sub 2} were measured and used to determine the energy transfer probability distribution function, P(E,E′), in the large ΔE region. P(E,E′) was then fit to a bi-exponential function and extrapolated to the low ΔE region. P(E,E′) and the biexponential fit data were used to determine the partitioning between weak and strong collisions as well as investigate molecular properties responsible for large collisional energy transfer events. Fermi's Golden rule was used to model the shape of P(E,E′) and identify which donor vibrational motions are primarily responsible for energy transfer. In general, the results suggest that low-frequency MFB vibrational modes are primarily responsible for strong collisions, and govern the shape and magnitude of P(E,E′). Where deviations from this general trend occur, vibrational modes with large negative anharmonicity constants are more efficient energy gateways than modes with similar frequency, while vibrational modes with large positive anharmonicity constants are less efficient at energy transfer than modes of similar frequency.« less
  • A three-dimensional quantum mechanical study of vibrational state resolved differential cross sections for the direct inelastic and charge transfer channels of the H{sup +}+H{sub 2} system has been carried out at {ital E}{sub cm} =20 eV using the infinite order sudden approximation (IOSA). Steric factors, opacity functions, angular distributions, and integral cross sections are calculated. The integral cross sections are in very good agreement with recent experimental results, whereas the angular distributions agree only partially with the experiments. A further comparison of both the theoretical and experimental results with semi-classical calculations based on the usual trajectory surface hopping method revealedmore » that the present quantum results provide a better description of the experimental observations. The likely shortcomings of the semiclassical method are discussed.« less
  • A three-dimensional quantum-mechanical study of vibrational, state-resolved differential cross sections (DCS) for the direct inelastic and for the charge-transfer scattering channels has been carried out for the H{sup +}+O{sub 2} system. The collision energy considered was {ital E}{sub c.m.}=23.0 eV, which is the same as that examined by Noll and Toennies in their experiments (J. Chem. Phys. 85, 3313 (1986)). The scattering treatment employed was the charge-transfer infinite-order sudden approximation (CT IOSA) with the vibrational states correctly expanded over the relevant adiabatic basis for each of the two electronic channels. The state-to-state DCS are found to follow closely the behaviormore » of the experimental quantities, both in the inelastic and the charge-transfer channels. Moreover, a careful comparison between the measured relative probabilities and computed values allows us to test in minute detail the efficiency of the scattering model and the reliability of the potential-energy surfaces employed. It is found that vibrational energy transfer is overestimated in the vibrational inelastic channels while in the charge-transfer inelastic channels the same energy transfer is slightly underestimated by the calculations. The total flux distribution, however, is found to be in very good accord with experiments. Angular distributions are also well reproduced both by the DCS and by the average energy-transfer values. The study of some of the CT IOSA quantities also allows us to establish clearly the importance of nonadiabatic transitions in enhancing vibrational inelasticity in the present system.« less