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Parity-Time symmetric system based on the thermoacoustic effect
Gaelle Poignand1, Come Olivier1, Guillaume Penelet1
1Laboratoire d'Acoustique de l'Université du Mans (LAUM), UMR-CNRS 6613, Institut d'Acoustique-Graduate School (IA-GS), CNRS, Le Mans Université, France.
The Journal of the Acoustical Society of America
|March 26, 2021
Summary
Researchers experimentally studied an acoustic Parity-Time (PT) symmetric system using thermoacoustic amplification. They achieved PT-symmetry and observed characteristic behaviors like symmetry breaking and exceptional points within a specific frequency range.
Area of Science:
- Acoustics
- Non-Hermitian Physics
- Wave Phenomena
Background:
- Parity-Time (PT) symmetry offers unique properties in non-Hermitian systems.
- Thermoacoustic amplification provides a mechanism for active gain in acoustic systems.
- Experimental realization of PT-symmetric acoustic systems is crucial for exploring novel wave phenomena.
Purpose of the Study:
- To experimentally investigate an acoustic Parity-Time (PT) symmetric system.
- To demonstrate the balance of gain and loss using thermoacoustic amplification.
- To explore PT-symmetry breaking and exceptional points in an acoustic waveguide.
Main Methods:
- Constructed a PT-symmetric acoustic system with two units connected via side branches to a waveguide.
- Utilized a thermoacoustic core in one unit for acoustic gain, balancing losses in the other.
- Adjusted two control parameters (unit impedance) to achieve PT-symmetry condition.
- Analyzed system behavior within a specific frequency range (45-60 Hz).
Main Results:
- Achieved a balanced gain-loss condition within the 45-60 Hz frequency range.
- Observed spontaneous Parity-Time (PT) symmetry breaking.
- Identified the existence of exceptional points characteristic of PT-symmetric systems.
- Demonstrated that the distance between units can tune the frequency of exceptional points.
Conclusions:
- The experimental acoustic PT-symmetric system successfully balances gain and loss.
- The system exhibits key PT-symmetric behaviors, including symmetry breaking and exceptional points.
- The distance between acoustic units serves as a parameter to control exceptional point frequencies.
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