2014/01/31 by Myungseok Eune, Yongwan Gim, Wontae Kim · 12 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Black Holes and Theoretical Physics #Black hole (networking) #Event horizon #Horizon #Negative energy #Observer (physics) #Quantum Electrodynamics and Casimir Effect #Scalar field #Schwarzschild metric #Schwarzschild radius #Unruh effect #gr-qc #hep-th
paper · pdf · doi:10.1142/s0217732314502150
published in Modern Physics Letters A 29(40), 1450215 (World Scientific) · 11 pages, 3 figures, references added, version to appear in MPLA
openalex publication_date 2014/12/18 · arxiv created 2014/12/24 · arxiv updated 2014/12/25 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We revisit the free-fall energy density of scalar fields semiclassically by employing the trace anomaly on a two-dimensional Schwarzschild black hole with respect to various black hole states in order to clarify whether something special at the horizon happens or not. For the Boulware state, the energy density at the horizon is always negative divergent, which is independent of initial free-fall positions. However, in the Unruh state the initial free-fall position is responsible for the energy density at the horizon and there is a critical point to determine the sign of the energy density at the horizon. In particular, a huge negative energy density appears when the freely falling observer is dropped just near the horizon. For the Hartle–Hawking state, it may also be positive or negative depending on the initial free-fall position, but it is always finite. Finally, we discuss physical consequences of these calculations.