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Updated: Apr 26, 2026
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Induction of Microstreaming by Nonspherical Bubble Oscillations in an Acoustic Levitation System
Published on: May 9, 2021
2.5K
Acoustic interactions between inversion symmetric and asymmetric two-level systems.
A Churkin1, D Barash, M Schechter
1Department of Physics, Ben Gurion University of the Negev, Beer Sheva 84105, Israel. Department of Computer Science, Ben Gurion University of the Negev, Beer Sheva 84105, Israel.
Summary
Tunneling two-level systems (TLSs) explain universal low-temperature acoustic properties in disordered solids. This study numerically calculates TLS-TLS interactions, revealing how symmetry and disorder influence these interactions, supporting existing models.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Acoustics
Background:
- Amorphous solids and disordered lattices exhibit universal low-temperature acoustic properties.
- This universality is linked to phonon attenuation by tunneling two-level systems (TLSs).
- TLS-phonon interactions mediate effective TLS-TLS interactions, crucial for glassy phase properties.
Purpose of the Study:
- To numerically calculate effective TLS-TLS interactions in the archetypal disordered lattice KBr:CN.
- To investigate the influence of TLS symmetry (inversion symmetric vs. asymmetric) and disorder on these interactions.
- To characterize TLS-TLS interactions in disordered lattices across various dilutions.
Main Methods:
- Numerical calculations using the conjugate gradients method.
- Analysis of effective TLS-TLS interactions for both symmetric (CN flips) and asymmetric (CN rotations) TLSs.
- Simulation in two and three dimensions, with and without disorder.
Main Results:
- The magnitude and spatial power law of TLS-TLS interactions depend significantly on TLS symmetry.
- Disorder alters the characteristics of TLS-TLS interactions.
- Observed dependencies align with predictions for disordered lattices at different dilution levels.
Conclusions:
- The study provides a detailed characterization of TLS-TLS interactions in disordered systems like KBr:CN.
- Results support the two-TLS model in explaining quantitative universality in phonon attenuation.
- The findings clarify the energy scale (≈ 1-3 K) of low-temperature universality in disordered solids.
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