Achieving very long lifetimes in optical lattices with pulsed cooling
  We have realized a one dimensional optical lattice for individual atoms with a lifetime >300 s, which is 5 times longer than previously reported. In order to achieve this long lifetime, it is necessary to laser cool the at-oms briefly every 20 s to overcome heating due to technical fluctuations in the trapping potential. Without cooling, we observe negligible atom loss within the first 20 s followed by an exponential decay with a 62 s time constant. We obtain quantitative agreement with the measured fluctuations of the trapping potential and the corresponding theoretical heating rates. 
Michael J. Gibbons, Soo Y. Kim, Kevin M. Fortier, Peyman Ahmadi, and   Michael S. Chapman