Persistent dynamic correlations in self-organized critical systems away from their critical point

16 pages, 12 figures.-- PACS nrs.: 05.65.+b, 05.40.-a, 52.25.Fi, 96.60.Rd.-- ArXiv pre-print available at: http://arxiv.org/abs/cond-mat/0503159We show that correlated dynamics and long time memory persist in self-organized criticality (SOC) systems even when forced away from the defined critical point that exists at vanishing drive strength. These temporal correlations are found for all levels of external forcing as long as the system is not overdriven. They arise from the same physical mechanism that produces the temporal correlations found at the vanishing drive limit, namely the memory of past events stored in the system profile. The existence of these correlations contradicts the notion that a SOC time series is simply a random superposition of events with sizes distributed as a power law, as has been suggested by previous studies.Support from DOE under grants DE-FG03-99ER54551 and DE-FG03-00ER54599 (a young investigator award) and NSF under grant ECS-0085647 are gratefully acknowledged.Publicad