Physical Review A
Coherent dipole transport in a small grid of Rydberg atoms
Hui Yu, F. Robicheaux
Abstract
We calculated the motion of one or two excitons through a small grid of Rydberg atoms. Both one- and two-dimensional grids were studied with the number of sites in a direction between 4 and 10. To mimic the possibility of nonperfect filling, calculations were performed with atoms randomly missing from sites. Results are presented for four qualitatively different situations. (1) The corners and edges, with the randomness of nonperfect filling, strongly affects the exciton motion and can pin the exciton. (2) For the case where a single exciton is simultaneously generated at two sites, the direction in which the exciton moves can be controlled by imprinting a phase difference on the two adjacent sites. (3) For the case where two excitons are generated at adjacent sites, calculations where a pair of excitons move through the grid are compared to the one exciton case to see whether exciton-exciton correlations are measurable. (4) The grid version of an exciton current can be defined by analogy to a continuity equation in one dimension and by using the analogy to a velocity operator in one, two, or three dimensions; for one dimension, the two definitions give similar results which means the direct measurement of the current in one dimension is possible.