Dr Maximilian Saller

  Cavity enhanced charge transfer rate constants as a function of driving force obtained using a partially linearized LSC formulation of FGR, compared to exact results. A new paper has recently been published in The Journal of Physical Chemistry Letters, demonstrating two LSC based approaches for obtaining accurate FGR rate constants for charge transfer systems within microcavities. In previous work ( JPCL ) we showed that quantum dynamics methods based on LSC can yield accurate results for the populations of cavity bound systems. In this work we demonstrate that LSC based approaches can in fact also be used to obtain accurate charge transfer rate constants for such systems, by applying linearization to the FGR framework for calculating rates. We show that both partially and fully linearized LSC approaches can yield highly accurate rate constants, with the former actually yielding quantum-mechanically exact results for the Hamiltonian we investigated. We also highlight the importan...

Atom-in-cavity populations using a number of different quasiclassical mapping Hamiltonian methods, compared to quantum mechanically exact benchmark data, shown in black. A new paper has recently been published in the Journal of Physical Chemistry Letters, applying both traditional and improved mapping approaches to benchmark models describing the physics of molecules in cavities. As in our previous paper ( JCTC 2020 ) we compare the performance of mean field Ehrenfest, the traditional LSC I and LSC II mapping methods and three improved mLSC approaches, which we developed in previous papers ( JCP 2019 and Faraday Disc. 2019 ). In this work we study a Hamiltonian which models the physics of a two- or three-level atom within a cavity. We are able to show that, in line with our previous work, the mLSC approaches constitute a considerable improvement, not just over mean field, but also over the traditional LSC I and LSC II methods at no extra cost. The ability of mapping methods such as th...

Expectation values of the Pauli matrices for a Spin-Boson Hamiltonian in the critical damping parameter regime, computed with a variety of mapping methods and compared to numerically exact QUAPI results. A new paper has recently been published in the Journal of Chemical Theory and Computation, wherein we benchmark the performance of mapping approach based dynamics methods. We compare the accuracy of traditional LSC I and LSC II approaches to a selection of modified, mLSC, versions, which make use of the improved population operators developed in previous papers ( JCP 2019 and Faraday Disc. 2019 ). We also include the windowing, SQC, approach, which constitutes and alternative strategy for improving traditional mapping, as well as mean field Ehrenfest dynamics. We apply these seven approaches to a selection of benchmark models, namely the Spin-Boson, Frenkel Bi-exciton and Tully's scattering models I and II. We find that both the mLSC and SQC approaches consistently consti...

Time dependent population of state n following excitation of state m of the FMO model at 77K. Our traceless operator approach is shown with dashed lines, traditional PBME with dash-dotted lines and exact HEOM benchmark results as solid lines. We have submitted a new paper on our modification of the traditional mapping population operators. We split this operator into the identity and a traceless component and then treat the identity exactly, as we known how it behaves in quantum mechanics. The result of using our definition of the population operator is a drastic increase in accuracy over the traditional definition, which for the systems we study actually approaches the numerically exact benchmark. arXiv Link

Over the last week, I had the privilege to attend the "Non-adiabatic quantum dynamics: From theory to experiment" CECAM workshop hosted at EPFL Lausanne. The meeting featured a number of excellent talks by leading researchers in the field of non-adiabatic dynamics from around the world. In addition a number of highly interesting posters were presented by postdoctoral and graduate students. Meeting attendees, copyright CECAM 2018 I enjoyed a number of very illuminating discussions with other researchers, which gave me insightful new perspectives on my own work as well as highlighting potential avenues for future collaborations. I am looking forward to developing my ideas based on the comments and questions I received over the last week. I had the privilege to present a poster titled "Correlation functions from non-adiabatic ring polymer molecular dynamics", which highlighted some results of my recent work in the group of Prof. Richardson. I demonstrated the...