Next Article in Journal
The Non-Equilibrium Statistical Distribution Function for Electrons and Holes in Semiconductor Heterostructures in Steady-State Conditions
Previous Article in Journal
Passive Decoy-State Quantum Key Distribution with Coherent Light
Previous Article in Special Issue
Space-Time Quantum Imaging
Open AccessArticle

Losing Information Outside the Horizon

Department of Physics, The Ohio State University, Columbus, OH 43210, USA
Academic Editor: Hiromi Saida
Entropy 2015, 17(6), 4083-4109;
Received: 11 June 2014 / Accepted: 3 June 2015 / Published: 12 June 2015
(This article belongs to the Special Issue Entropy and Spacetime)
Suppose we allow a system to fall freely from infinity to a point near (but not beyond) the horizon of a black hole. We note that in a sense the information in the system is already lost to an observer at infinity. Once the system is too close to the horizon it does not have enough energy to send its information back because the information carrying quanta would get redshifted to a point where they get confused with Hawking radiation. If one attempts to turn the infalling system around and bring it back to infinity for observation then it will experience Unruh radiation from the required acceleration. This radiation can excite the bits in the system carrying the information, thus reducing the fidelity of this information. We find the radius where the information is essentially lost in this way, noting that this radius depends on the energy gap (and coupling) of the system. We look for some universality by using the highly degenerate BPS ground states of a quantum gravity theory (string theory) as our information storage device. For such systems one finds that the critical distance to the horizon set by Unruh radiation is the geometric mean of the black hole radius and the radius of the extremal hole with quantum numbers of the BPS bound state. Overall, the results suggest that information in gravity theories should be regarded not as a quantity contained in a system, but in terms of how much of this information is accessible to another observer. View Full-Text
Keywords: black holes; information; string theory black holes; information; string theory
MDPI and ACS Style

Mathur, S.D. Losing Information Outside the Horizon. Entropy 2015, 17, 4083-4109.

Show more citation formats Show less citations formats

Article Access Map by Country/Region

Only visits after 24 November 2015 are recorded.
Search more from Scilit
Back to TopTop