Achieving ultrafast topologically-protected vibrational energy transfer in a dimer chain

Abstract

Vibrational energy transfer through molecules plays a crucial role in many chemical and biological processes. Understanding the transfer rates and mechanisms may not only shed light on these processes, but may also lead to technological developments in the areas of quantum information processing and molecular electronics. Recently, it was shown that it is possible to induce robust long-range transfer of strongly correlated particles in a one-dimensional dimer chain model by tuning the chain’s topological phase. In the present work, we consider the effect of coupling this dimer chain to a chain of coupled harmonic oscillators on the energy transfer dynamics. This is accomplished by performing mixed quantum–classical dynamics simulations of the composite system, in which the dimer chain is treated quantum mechanically while the chain of coupled harmonic oscillators is treated classically. We investigate the energy transfer dynamics for a wide range of model parameters and disorders by monitoring the time-dependent population of each mode in the dimer chain. Interestingly, when the dimer chain is in its topologically non-trivial phase, we find that the population transfers from one end of the chain to the other (without passing through the intermediate sites) on a ∼100 fs timescale, in contrast to the ∼10 ps timescale observed in the original model. In addition, this transfer is found to be quite robust in the presence of weak disorder in the dimer chain. These results point to the possibility of achieving ultrafast, topologically-protected energy transfer in polymeric materials with appropriate molecular compositions and architectures.