Tensile Strength and the Mining of Black Holes
Abstract
There are a number of important thought experiments that involve raising and lowering boxes full of radiation in the vicinity of black hole horizons. This Letter looks at the limitations placed on these thought experiments by the null energy condition, which imposes a fundamental bound on the tensilestrengthtoweight ratio of the materials involved, makes it impossible to build a box near the horizon that is wider than a single wavelength of the Hawking quanta, and puts a severe constraint on the operation of “space elevators” near black holes. In particular, it is shown that proposals for mining black holes by lowering boxes near the horizon, collecting some Hawking radiation, and dragging it out to infinity cannot proceed nearly as rapidly as has previously been claimed. As a consequence of this limitation, the boxes and all the moving parts are superfluous and black holes can be destroyed equally rapidly by threading the horizon with strings.
 Publication:

Physical Review Letters
 Pub Date:
 November 2013
 DOI:
 10.1103/PhysRevLett.111.211301
 arXiv:
 arXiv:1207.3342
 Bibcode:
 2013PhRvL.111u1301B
 Keywords:

 04.70.Dy;
 04.70.Bw;
 Quantum aspects of black holes evaporation thermodynamics;
 Classical black holes;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Theory
 EPrint:
 23 pages