Amplification and suppression of system-bath correlation effects in an open many-body system

Understanding the rich dynamics of open quantum systems is of fundamental interest to quantum control and quantum information processing. By considering an open system of many identical two-level atoms interacting with a common bath, we show that effects of system-bath correlations are amplified in a many-body system via the generation of a short time scale inversely proportional to the number of atoms. Effects of system-bath correlations are therefore considerable even when each individual atom interacts with the bath weakly. We further show that correlation-induced dynamical effects may still be suppressed via the dynamical decoupling approach, but they present a challenge for quantum state protection as the number of atom increases.