Entanglement entropy of the black hole horizon - art. no. 104016

We examine the possibility that, when a black hole is formed, the informati on on the collapsed star is stored as the entanglement entropy between the outside and the thin region (of the order of the Planck length) of the insi de of the horizon. For this reason, we call this the entanglement entropy o f the black hole "horizon." We construct two models: one is in Minkowski sp acetime and the other is in the Rindler wedge. To calculate the entropy exp licitly, we assume that the thin regions of the order of the Planck length of the outside and the inside of the horizon are completely entangled by qu antum effects. We also use the property of the entanglement entropy that it is symmetric under an interchange of the observed and unobserved subsystem s. Our setting and this symmetric property substantially reduce the needed numerical calculations. As a result of our analysis, we can explain the Bek enstein-Hawking entropy itself (rather than its correction by matter fields ) in the context of entanglement entropy.