Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Physical Sciences and Mathematics
Ergoregion Instability Of Black Hole Mimickers, Paolo Pani, Vitor Cardoso, Mariano Cadoni, Marco Cavaglia
Ergoregion Instability Of Black Hole Mimickers, Paolo Pani, Vitor Cardoso, Mariano Cadoni, Marco Cavaglia
Physics Faculty Research & Creative Works
Ultra-compact, horizonless objects such as gravastars, boson stars, wormholes and superspinars can mimick most of the properties of black holes. Here we show that these "black hole mimickers" will most likely develop a strong ergoregion instability when rapidly spinning. Instability timescales range between ∼ 10-5s and ∼ weeks depending on the object, its mass and its angular momentum. For a wide range of parameters the instability is truly effective. This provides a strong indication that astrophysical ultra-compact objects with large rotation are black holes.
Electron Self-Energy In The Presence Of A Magnetic Field: Hyperfine Splitting And G Factor, Vladimir A. Yerokhin, Ulrich D. Jentschura
Electron Self-Energy In The Presence Of A Magnetic Field: Hyperfine Splitting And G Factor, Vladimir A. Yerokhin, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
A high-precision numerical calculation is reported for the self-energy correction to the hyperfine splitting and to the bound-electron g factor in hydrogenlike ions with low nuclear charge numbers. The binding nuclear Coulomb field is treated to all orders, and the nonperturbative remainder beyond the known Zα-expansion coefficients is determined. For the 3He+ ion, the nonperturbative remainder yields a contribution of -450Hz to the normalized difference of the 1S and 2S hyperfine-structure intervals, to be compared with the experimental uncertainty of 71 Hz and with the theoretical error of 50 Hz due to other contributions. In the case of …