Origin of Quasinormal Modes in Semi-Open Systems

Area of Science:

• Astrophysics
• Experimental Physics
• Acoustics

Background:

• Astrophysical black holes are open systems radiating quasinormal modes (QNMs) to infinity.
• Laboratory analogs of black holes are finite-sized, posing challenges for experimental QNM excitation.

Purpose of the Study:

• To investigate how enclosing a toy black hole model with a partially reflecting wall influences its QNM spectrum.
• To establish a connection between the QNM spectra of open and finite-sized systems.
• To explore the excitation of QNMs in laboratory settings with unavoidable noise and finite-size effects.

Main Methods:

• A toy-model black hole system was simulated.
• The effect of a partially reflecting wall with adjustable reflectivity on the QNM spectrum was analyzed.
• The excitation of QNMs by incoherent background noise was demonstrated.

Main Results:

• A continuous connection was found between the QNM spectra of open and finite-sized systems.
• QNMs in the enclosed system were shown to be easily excited by background noise.
• The study provides a framework for understanding QNMs in realistic laboratory conditions.

Conclusions:

• Enclosing a system with a partially reflecting wall allows for the study of QNMs in finite-sized analogs.
• Incoherent background noise can effectively excite QNMs, suggesting experimental feasibility.
• This work paves the way for laboratory studies of black hole quasinormal modes and compact objects.