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Magnetic-field-induced non-Gaussian fluctuations in macroscopic equilibrium systems.
K E Nagaev1, O S Ayvazyan, N Yu Sergeeva
1Institute of Radioengineering and Electronics, Mokhovaya 11-7, Moscow, 125009 Russia.
Physical Review Letters
|January 15, 2011
Summary
A magnetic field can create electrical current fluctuations in certain materials, even without applied voltage. This finding offers a new way to test theories about energy fluctuations in systems far from equilibrium.
Area of Science:
- Condensed matter physics
- Nonlinear dynamics
- Statistical mechanics
Background:
- Macroscopic inhomogeneous systems exhibit complex electrical properties.
- Understanding current fluctuations is crucial for characterizing electronic behavior.
- Nonequilibrium fluctuation relations provide fundamental insights into statistical mechanics.
Purpose of the Study:
- To investigate the magnetic-field-dependent nonlinear conductance and noise in 2D macroscopic inhomogeneous systems.
- To determine if a magnetic field can induce nonzero current fluctuations (third cumulant) in systems lacking specific symmetry, even at equilibrium.
- To explore the relationship between these fluctuations and system properties like spectral density and average current.
Main Methods:
- Theoretical calculation of nonlinear conductance and noise.
- Analysis of current cumulants in the presence of a magnetic field.
- Comparison with theoretical frameworks for mesoscopic quantum-coherent systems.
Main Results:
- A magnetic field induces a nonzero third cumulant of electric current in 2D inhomogeneous systems lacking specific symmetry, even at equilibrium.
- This induced cumulant is proportional to voltage derivatives of spectral density and average current.
- The magnitude of these quantities can be significantly larger than in mesoscopic systems.
Conclusions:
- The studied system provides a robust experimental platform for testing nonequilibrium fluctuation relations.
- The findings highlight the role of magnetic fields in generating nonequilibrium phenomena in macroscopic systems.
- This work bridges the understanding of fluctuations in mesoscopic and macroscopic electronic systems.
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