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Persistent tunneling currents and magnetic-field effects in glasses
1Université Bordeaux 1, CPMOH, 351 cours de la Libération, 33405 Talence, France.
Physical Review Letters
|February 28, 2002
Summary
Researchers explain unexpected dielectric constant changes in insulating glasses using a two-level system model. This model reveals quantum states with circular currents, leading to oscillations linked to a magnetic flux quantum.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Mechanics
Background:
- Insulating glasses exhibit unusual dielectric constant variations under static magnetic fields.
- Observed oscillations suggest a connection to fundamental quantum phenomena, specifically a flux quantum.
Purpose of the Study:
- To propose a theoretical model explaining the observed magnetic field dependence of the dielectric constant in insulating glasses.
- To elucidate the underlying quantum mechanical principles governing these phenomena.
Main Methods:
- Development of a theoretical model based on pairs of two-level systems.
- Analysis of quantum states arising from weak interactions between these systems.
- Investigation of the dynamic susceptibility under experimental conditions.
Main Results:
- The model predicts quantum states with net circular currents.
- Energy levels demonstrate a linear dependence on the applied magnetic field.
- Simulated dynamic susceptibility exhibits oscillatory behavior with an effective flux quantum of approximately 10^-5 h/e.
Conclusions:
- The proposed two-level system model successfully explains the experimentally observed magnetic field-induced oscillations in the dielectric constant of insulating glasses.
- The findings highlight the role of quantum effects in the macroscopic properties of disordered materials.
- The study provides a theoretical framework for understanding complex phenomena in condensed matter systems.