Quantum information cannot be completely hidden in correlations: Implications for the black-hole information paradox

Quantum information cannot be completely hidden in correlations: Implications for the black-hole information paradox

Braunstein, S.L. and Pati, A.K.
(2007): Physical Review Letters 98, 080502-1/4 (PDF)

ABSTRACT: Can quantum-information theory shed light on black-hole evaporation? By entangling the in-fallen matter with an external system we show that the black-hole information paradox becomes more severe, even for cosmologically sized black holes. We rule out the possibility that the information about the infallen matter might hide in correlations between the Hawking radiation and the internal states of the black hole. As a consequence, either unitarity or Hawking's semiclassical predictions must break down. Any resolution of the black-hole information crisis must elucidate one of these possibilities.