In one minute

Alhambra, Styliaris, Rodríguez-Briones, Sikora and Martín-Martínez ask when energy can be extracted locally from a two-part quantum system that is strongly coupled and entangled. The task is expected to be restricted by the entanglement present in the system's low-energy eigenstates. Using semidefinite programming for the first time in this context, they find necessary and sufficient conditions for when such local extraction is impossible. They strengthen an earlier result by Frey and colleagues with a quantitative bound on the temperature threshold where this passivity sets in. The limit also holds for thermal states in the thermodynamic limit when spatial correlations decay fast enough, and they give numerical examples.

Fundamental Limitations to Local Energy Extraction in Quantum Systems