Abstract
The ground-state density matrix for a massless free field is traced over the degrees of freedom residing inside an imaginary sphere; the resulting entropy is shown to be proportional to the area (and not the volume) of the sphere. Possible connections with the physics of black holes are discussed.
- Received 15 March 1993
DOI:https://doi.org/10.1103/PhysRevLett.71.666
©1993 American Physical Society