In a recent paper, PRL 114 100404, 2015, Raeisi and Mosca gave a limit for cooling with Heat-Bath Algorithmic Cooling (HBAC). Here we show how to exceed that limit by having correlation in the qubits-bath interaction.
Cite
@article{arxiv.1506.01778,
title = {Comments on: Asymptotic Bound for Heat-Bath Algorithmic Cooling},
author = {Nayeli Azucena Rodriguez-Briones and Jun Li and Xinhua Peng and Tal Mor and Yossi Weinstein and Raymond Laflamme},
journal= {arXiv preprint arXiv:1506.01778},
year = {2015}
}