We investigate the correlation harvesting protocol for mutual information
between two Unruh-DeWitt detectors in a static BTZ black hole spacetime. Here,
the effects coming from communication and change in proper separation of the
detectors are set to be negligible so that only a black hole affects the
extracted mutual information. We find that, unlike the entanglement harvesting
scenario, harvested mutual information is zero only when a detector reaches an
event horizon, and that although the Hawking effect and gravitational redshift
both affect the extraction of mutual information, it is extreme Hawking
radiation that inhibits the detectors from harvesting.Comment: 10 pages, 4 figures; v2: fixed typo