NHEG Mechanics: Laws of Near Horizon Extremal Geometry (Thermo)Dynamics

Oct 14, 2013
32 pages
Published in:
  • JHEP 03 (2014) 014
  • Published: 2014
e-Print:
Report number:
  • IPM-P-2013-033

Citations per year

2012201520182021202402468
Abstract: (arXiv)
Near Horizon Extremal Geometries (NHEG) are solutions to gravity theories with SL(2,R)×U(1)N SL(2,R) \times U(1)^N (for some N) symmetry, are smooth geometries and have no event horizon, unlike black holes. Following the ideas by R. M. Wald, we derive laws of NHEG dynamics, the analogs of laws of black hole dynamics for the NHEG. Despite the absence of horizon in the NHEG, one may associate an entropy to the NHEG, as a Noether-Wald conserved charge. We work out entropy and entropy perturbation laws, which are respectively universal relations between conserved Noether charges corresponding to the NHEG and a system probing the NHEG. Our entropy law is closely related to Sen's entropy function. We also discuss whether the laws of NHEG dynamics can be obtained from the laws of black hole thermodynamics in the extremal limit.
Note:
  • 33 pages, No figures, To appear in JHEP
  • Black Holes
  • Space-Time Symmetries
  • Classical Theories of Gravity
  • Gauge Symmetry
  • entropy: perturbation
  • black hole: thermodynamics
  • charge: conservation law
  • conservation law: Noether
  • charge: Noether
  • horizon