Research Article

General Relativity and Gravitation

, Volume 42, Issue 6, pp 1457-1467

First online:

The effect of negative-energy shells on the Schwarzschild black hole

  • Jeffrey S. HazbounAffiliated withDepartment of Physics, Oregon State University Email author 
  • , Tevian DrayAffiliated withDepartment of Mathematics, Oregon State University

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We construct Penrose diagrams for Schwarzschild spacetimes joined by massless shells of matter, in the process correcting minor flaws in the similar diagrams drawn by Dray and ’t Hooft (Commun Math Phys 99:613–625, 1985), and confirming their result that such shells generate a horizon shift. We then consider shells with negative energy density, showing that the horizon shift in this case allows for travel between the heretofore causally separated exterior regions of the Schwarzschild geometry. These drawing techniques are then used to investigate the properties of successive shells, joining multiple Schwarzschild regions. Again, the presence of negative-energy shells leads to a causal connection between the exterior regions, even in (some) cases with two successive shells of equal but opposite total energy.


Black holes Negative energy Wormholes Shells