Enhancing qubit information with quantum thermal noise

Informational quantities characterizing the qubit are analyzed in the presence of quantum thermal noise modeling the decoherence process due to interaction with the environment represented as a heat bath at arbitrary temperature. Nontrivial regimes of variation are reported for the informational quantities, which do not necessarily degrade monotonically as the temperature of the thermal noise increases, but on the contrary can experience nonmonotonic variations where higher noise temperatures can prove more favorable. Such effects show that increased quantum decoherence does not necessarily entail poorer informational performance, and they are related to stochastic resonance or noise-enhanced efficiency in information processing.