The thermodynamic meaning of negative entropy

          @misc{ scivideos_PIRSA:10100086,
            doi = {10.48660/10100086},
            url = {https://pirsa.org/10100086},
            author = {},
            keywords = {Quantum Foundations},
            language = {en},
            title = {The thermodynamic meaning of negative entropy },
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2010},
            month = {oct},
            note = {PIRSA:10100086 see, \url{https://scivideos.org/index.php/pirsa/10100086}}
          }
          

Abstract

Landauer's erasure principle states that there is an inherent work cost associated with all irreversible operations, like the erasure of the data stored in a system. The necessary work is determined by our uncertainty: the more we know about the system, the less it costs to erase it. Here, we analyse erasure in a general setting where our information about that system can be quantum mechanical. In this scenario, our uncertainty, measured by a conditional entropy, may become negative. We establish a general relation between quantum conditional entropies and a physical quantity, the work cost of erasure. As a consequence, we obtain a thermodynamic interpretation of negative entropies: they quantify the work that can be gained by a quantum observer erasing a system. (arXiv: 1009.1630)