Tidal response and near-horizon boundary conditions for spinning exotic compact objects

Baoyi Chen; Qingwen Wang; Yanbei Chen

doi:10.1103/physrevd.103.104054

Tidal response and near-horizon boundary conditions for spinning exotic compact objects

Physical Review D ◽

10.1103/physrevd.103.104054 ◽

2021 ◽

Vol 103 (10) ◽

Author(s):

Baoyi Chen ◽

Qingwen Wang ◽

Yanbei Chen

Keyword(s):

Boundary Conditions ◽

Compact Objects ◽

Tidal Response

Download Full-text

A WKB formula for echoes

International Journal of Geometric Methods in Modern Physics ◽

10.1142/s0219887819501810 ◽

2019 ◽

Vol 16 (12) ◽

pp. 1950181 ◽

Cited By ~ 1

Author(s):

Lorenzo Sebastiani ◽

Luciano Vanzo ◽

Sergio Zerbini

Keyword(s):

Black Holes ◽

Boundary Conditions ◽

Quantum Effects ◽

Compact Objects ◽

Quantum Level ◽

Unified Approach ◽

Classical Level

We present a unified approach for the study of idealized gravitational compact objects like wormholes (WHs) and horizonless stars, here simulated by the presence of boundary conditions at a deeply inner wall. At the classical level, namely neglecting quantum effects, the presence of the wall leads to characteristic echoes following the usual ringdown phase, such that it can discriminate black holes from other horizonless, and probably exotic, compact objects. With regard to this issue, an analytical though approximated expression for the complex frequencies of the quasinormal echoes is found and discussed. At the quantum level, we show that static WHs do not radiate.

Download Full-text

Use of the Magnetostatic Analogue In Electromagnetic Lens Engineering

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100068795 ◽

1970 ◽

Vol 28 ◽

pp. 360-361

Author(s):

John W. Coleman

Keyword(s):

Boundary Conditions ◽

High Performance ◽

Force Fields ◽

Optical Design ◽

Direct Conversion ◽

Design Engineering ◽

Design Data ◽

Scalar Potentials ◽

Geometric Elements ◽

At Will

In the design engineering of high performance electromagnetic lenses, the direct conversion of electron optical design data into drawings for reliable hardware is oftentimes difficult, especially in terms of how to mount parts to each other, how to tolerance dimensions, and how to specify finishes. An answer to this is in the use of magnetostatic analytics, corresponding to boundary conditions for the optical design. With such models, the magnetostatic force on a test pole along the axis may be examined, and in this way one may obtain priority listings for holding dimensions, relieving stresses, etc..The development of magnetostatic models most easily proceeds from the derivation of scalar potentials of separate geometric elements. These potentials can then be conbined at will because of the superposition characteristic of conservative force fields.

Download Full-text