scholarly journals Quasinormal mode analysis in BEC acoustic black holes

2007 ◽  
Vol 75 (8) ◽  
Author(s):  
C. Barceló ◽  
A. Cano ◽  
L. J. Garay ◽  
G. Jannes
Keyword(s):  
Black Holes ◽  
Quasinormal Mode ◽  
Mode Analysis ◽  
Acoustic Black Holes

scholarly journals Supersonic velocities in noncommutative acoustic black holes

2012 ◽  
Vol 85 (2) ◽  
Author(s):  
M. A. Anacleto ◽  
F. A. Brito ◽  
E. Passos
Keyword(s):  
Black Holes ◽  
Supersonic Velocities ◽  
Acoustic Black Holes

Sound absorption based on Micro-perforated panels and Acoustic Black Hole principle

2021 ◽  
Vol 263 (6) ◽  
pp. 548-555
Author(s):  
Xiaoqi Zhang ◽  
Li Cheng
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Sound Absorption ◽  
Practical Application ◽  
Inner Radius ◽  
Simulation Results ◽  
Structural Configurations ◽  
Acoustic Black Holes ◽  
Sound Reduction ◽  
Bending Wave

Acoustic black holes (ABHs) have been so far investigated mainly for bending wave ma-nipulation in mechanical structures such as beams or plates. The investigations on ABHs for sound wave manipulation, referred to as Sonic black holes (SBHs) are scarce. Existing SBH structure for sound reduction in air is typically formed by putting a set of rings inside a duct wall with decreasing inner radius according to a power law. As such, the structure is very complex and difficult to be practically realized, which hampers the practical application of SBHs for sound reduction. This study explores the possibilities of achieving SBH effects using other types of structural configurations. In particular, micro-perforated panels are proposed to be introduced into the conventional SBH structure, and the simulation results show that the new formed SBH structure is simpler in configuration in terms of number of rings and more efficient in terms of sound energy trapping and dissipation.

scholarly journals Quasinormal modes and van der Waals-like phase transition of charged AdS black holes in Lorentz symmetry breaking massive gravity

2019 ◽  
Vol 28 (09) ◽  
pp. 1950113 ◽  
Author(s):  
Bin Liang ◽  
Shao-Wen Wei ◽  
Yu-Xiao Liu
Keyword(s):  
Phase Transition ◽  
Black Holes ◽  
Black Hole ◽  
Symmetry Breaking ◽  
Quasinormal Modes ◽  
Massive Gravity ◽  
Quasinormal Mode ◽  
Large Black Hole ◽  
Sign Change ◽  
Lorentz Symmetry Breaking

Using the quasinormal modes of a massless scalar perturbation, we investigate the small/large black hole phase transition in the Lorentz symmetry breaking massive gravity. We mainly focus on two issues: (i) the sign change of slope of the quasinormal mode frequencies in the complex-[Formula: see text] diagram; (ii) the behaviors of the imaginary part of the quasinormal mode frequencies along the isobaric or isothermal processes. For the first issue, our result shows that, at low fixed temperature or pressure, the phase transition can be probed by the sign change of slope. While increasing the temperature or pressure to certain values near the critical point, there will appear the deflection point, which indicates that such method may not be appropriate to test the phase transition. In particular, the behavior of the quasinormal mode frequencies for the small and large black holes tend to be the same at the critical point. For the second issue, it is shown that the nonmonotonic behavior is observed only when the small/large black hole phase transition occurs. Therefore, this property can provide us with an additional method to probe the phase transition through the quasinormal modes.

scholarly journals Low reflection effect by 3D printed functionally graded acoustic black holes

2019 ◽  
Vol 450 ◽  
pp. 96-108 ◽  
Author(s):  
Wei Huang ◽  
Hui Zhang ◽  
Daniel J. Inman ◽  
Jinhao Qiu ◽  
Carlos E.S. Cesnik ◽  
...  
Keyword(s):  
Black Holes ◽  
Functionally Graded ◽  
Reflection Effect ◽  
3D Printed ◽  
Acoustic Black Holes

scholarly journals QUASINORMAL MODES AND LATE-TIME TAILS OF CANONICAL ACOUSTIC BLACK HOLES

2007 ◽  
Vol 16 (07) ◽  
pp. 1211-1218 ◽  
Author(s):  
PING XI ◽  
XIN-ZHOU LI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Wave Propagation ◽  
Angular Momentum ◽  
Numerical Method ◽  
Time Scale ◽  
Quasinormal Modes ◽  
Late Time ◽  
Classical Wave ◽  
Acoustic Black Holes

In this paper, we investigate the evolution of classical wave propagation in the canonical acoustic black hole by a numerical method and discuss the details of the tail phenomenon. The oscillating frequency and damping time scale both increase with the angular momentum l. For lower l, numerical results show the lowest WKB approximation gives the most reliable result. We also find that the time scale of the interim region from ringing to tail is not affected obviously by changing l.

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