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dc.contributor.authorShim, Sangwoo
dc.contributor.authorAspuru-Guzik, Alan
dc.date.accessioned2013-02-13T16:48:37Z
dc.date.issued2012
dc.identifier.citationShim, Sangwoo, and Alán Aspuru-Guzik. 2012. Path integral Monte Carlo with importance sampling for excitons interacting with an arbitrary phonon bath. The Journal of Chemical Physics 137(22): 22A538.en_US
dc.identifier.issn0021-9606en_US
dc.identifier.issn1089-7690en_US
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:10288716
dc.description.abstractThe reduced density matrix of excitons coupled to a phonon bath at a finite temperature is studied using the path integral Monte Carlo method. Appropriate choices of estimators and importance sampling schemes are crucial to the performance of the Monte Carlo simulation. We show that by choosing the population-normalized estimator for the reduced density matrix, an efficient and physically-meaningful sampling function can be obtained. In addition, the nonadiabatic phonon probability density is obtained as a byproduct during the sampling procedure. For importance sampling, we adopted the Metropolis-adjusted Langevin algorithm. The analytic expression for the gradient of the target probability density function associated with the population-normalized estimator cannot be obtained in closed form without a matrix power series. An approximated gradient that can be efficiently calculated is explored to achieve better computational scaling and efficiency. Application to a simple one-dimensional model system from the previous literature confirms the correctness of the method developed in this manuscript. The displaced harmonic model system within the single exciton manifold shows the numerically exact temperature dependence of the coherence and population of the excitonic system. The sampling scheme can be applied to an arbitrary anharmonic environment, such as multichromophoric systems embedded in the protein complex. The result of this study is expected to stimulate further development of real time propagation methods that satisfy the detailed balance condition for exciton populations.en_US
dc.description.sponsorshipChemistry and Chemical Biologyen_US
dc.language.isoen_USen_US
dc.publisherAmerican Institute of Physicsen_US
dc.relation.isversionofdoi:10.1063/1.4751487en_US
dc.relation.hasversionhttp://arxiv.org/abs/1203.6674en_US
dash.licenseOAP
dc.subjectcoherenceen_US
dc.subjectdensity functional theoryen_US
dc.subjectimportance samplingen_US
dc.subjectphonon-exciton interactionsen_US
dc.subjectproteinsen_US
dc.titlePath Integral Monte Carlo with Importance Sampling for Excitons Interacting with an Arbitrary Phonon Bathen_US
dc.typeJournal Articleen_US
dc.description.versionAuthor's Originalen_US
dc.relation.journalThe Journal of Chemical Physicsen_US
dash.depositing.authorAspuru-Guzik, Alan
dc.date.available2013-02-13T16:48:37Z
dc.identifier.doi10.1063/1.4751487*
dash.contributor.affiliatedAspuru-Guzik, Alan


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