Negative Quantum Vacuum Entropy is Puzzling
Conducting sphere interacting with conducting plane, and two conducting spheres interacting
Negative entropy for perfectly conducting and Drude spheres (a Drude nanoparticle has vanishing magnetic polarizability)
It has recently been discovered that nearby objects, such as conducting spheres, atoms, or nanoparticles, interacting through the quantum vacuum, exhibit regions where the entropy of the system goes negative. This occurs when the temperature times the separation distance (in natural units) is of order one. The physical significance of this surprising result is still under investigation, and was the subject of two recent papers of Kim Milton with prominent German and French theorists.
Whether the negative entropy discovered has anything to do with that occuring with living systems (Schrodinger) or that which might occur in black holes is a matter of speculation.
See also: "Negative Casimir Entropies in Nanoparticle Interactions," by K. A. Milton, Romain Guerout, Gert-Ludwig Ingold, Astrid Lambrecht, and Serge Reynaud, arXiv:1405.0311, J. Phys.: Condens. Matter 27, 214003 (2015), and "Geometric origin of negative Casimir entropies: A scattering channel analysis," by Gert-Ludwig Ingold, Stefan Umrath, Michael Hartmann, Romain Guerout, Astrid Lambrecht, Serge Reynaud, and Kimball A. Milton, arXiv:1411.1866, Phys. Rev. E. 91, 033203 (2015).