Quantum Effects in Biological System (QuEBS) in Vilnius

The group had a significant contribution at this year's QuEBS workshop held from July 10th to July 13th in Vilnius, Lithuania

Vilnius University tower

Church-laden panorama of Vilnius from the top of the university tower.

Traditionally, the presence of our research group at the QuEBS workshop is significant. This year we arrived with seven researchers presenting three oral contributions and three posters.

Joachim Seibt presented our recent work on method to treat non-adiabatic effects in resonance coupling in the frame-work of the hierarchical equations of motion (HEOM). One of the main results of this work (apart from the fact the HEOM description of the resonance coupling dependent on "bath" coordinates has been achieved) is the concept of operators on HEOM space. With this concept, one can evaluate action of operators depending on bath variables on the density matrix and auxiliary density operators of the hierarchy and e.g. evaluate expectation values of operators that nominally belong to the bath. This concept is of general interest beyond the particular application we demonstrated in the talk and our recently submitted paper.

Sayeh Rajabi presented a poster on her recent work on combining the standard perturbative approaches to the calculation of density matrix dynamics into one framework. In this work we extent the usual combined Redfield-Förster method so that in relatively wide range of parameters, it agrees with the numerically exact calculations performed by the HEOM method.

Vláďa Sláma came to QuEBS with his calculations of optical and energy transfer properties of Fluorographene, the 2D material we proposed some time ago as a good biomimetic medium. We are nearing a stage in which we would be able to perform reliable theoretical predictions of properties line energy gaps, spectral densities and resonance couplings between defects on Fluorographene.

Pavel Malý presented a poster on the problem of trapping of excitation in low-energy states. This issue has been marked during the last year's QuEBS in Jerusalem, Israel, as one of the largest mysteries of Quantum Biology. We believe that while a bit counter intuitive, the trap avoidance and detrapping are actually a part of the standard picture of photosynthetic energy transfer. Involvement of nuclear vibrations, which we study in our contribution, helps to speed up the process of detrapping (when trapping happens) or helps to avoid the trap.

Václav Perlík has delivered a lecture on his modeling of excitation energy transfer in perylene dyads. This work has be greatly aided by quantum chemical calculations by Vlaďa Sláma and it has been done in collaboration with Jürgen Hauer's lab now in TU München, Germany.

The last oral contribution of our extended group to the QuEBS conference was the presentation of František Šanda about finite pulse effects in non-linear spectroscopy. The experimentally very important issue of pulse overlap effects and finite pulse effects in general was discussed based on an analytical model.