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Non-Gaussian noise in quantum spin glasses and interacting two-level systems
1Department of Physics, Indiana University, Bloomington, IN 47405, USA.
Physical Review Letters
|October 3, 2001
Summary
This study introduces a model for non-Gaussian 1/f noise using quantum Ising spin systems. A key interaction term generates this non-Gaussian noise, even in equilibrium, with a universal 1/f power spectrum.
Area of Science:
- Condensed matter physics
- Statistical mechanics
- Quantum systems
Background:
- 1/f noise is common in physical systems but often assumed to be Gaussian.
- Non-Gaussian noise is less understood and harder to model.
- Quantum Ising spin systems offer a platform to explore complex noise phenomena.
Purpose of the Study:
- To develop a general model for non-Gaussian 1/f noise.
- To investigate the origin of non-Gaussian noise in quantum systems.
- To analyze the spectral properties of this noise.
Main Methods:
- Utilizing a general model of an infinite-range quantum Ising spin system in the paramagnetic state.
- Identifying a dilatation interaction term in the system's dynamics.
- Applying a dynamical mean-field approximation for analysis.
Main Results:
- A dilatation interaction term was identified that generates non-Gaussian noise.
- This noise generation persists in the thermodynamic limit, bypassing the central limit theorem.
- The second-order spectrum (noise of the noise) exhibits a universal 1/f form.
Conclusions:
- The quantum Ising spin model provides a valid framework for generating non-Gaussian 1/f noise.
- The identified interaction mechanism offers a new route to understanding non-Gaussian noise in physical systems.
- The universal 1/f nature of the noise spectrum is a significant finding.