Conformation and dynamics of model polymer in connected chamber-pore system

Erica J. Saltzman and Murugappan Muthukumar

Single polymer chains under spatially heterogeneous confinement are investigated through simulation of a chain in an infinite linear series of chambers and pores. Conformational properties studied include the number of occupied chambers and the radius of gyration along the chamber axis, both of which vary with chain length and chamber size according to simple scaling predictions. The evolution of the dynamics is suggestive of a substantial barrier, independent of chain length, that controls the large-scale motion for short-enough chains in large-enough chambers. Other known signatures of anomalous, nondiffusive dynamics are also observed. The onset of barrier-controlled or anomalous dynamics is conjectured to be the result of chains occupying only a small number of chambers simultaneously.

J. Chem. Phys. 131, 214903 (2009)

Highly efficient energy excitation transfer in light-harvesting complexes: The fundamental role of noise-assisted transport

F. Caruso, A. W. Chin, A. Datta, S. F. Huelga, and M. B. Plenio

The uncontrollable interaction of the transmission network with a noisy environment is usually assumed to deteriorate its transport capacity, especially so when the system is fundamentally quantum mechanical. Here key mechanisms are identified through which noise such as dephasing, perhaps counter intuitively, may actually aid transport through a dissipative network by opening up additional pathways for excitation transfer. It is shown that these are processes that lead to the inhibition of destructive interference and exploitation of line broadening effects. Results indicate that, in general, it is the careful interplay of quantum mechanical features and the unavoidable environmental noise that will lead to an optimal system performance.

J. Chem. Phys. 131, 105106 (2009)