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Updated: Jul 24, 2025
11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
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Current Noise of Hydrodynamic Electrons.
1Department of Physics, Ohio State University, Columbus, Ohio 43202, USA.
Physical Review Letters
|July 7, 2023
Summary
Researchers generalized Johnson-Nyquist noise theory for hydrodynamic electron systems. This advancement is crucial for accurate primary thermometry, enabling precise electron temperature measurements even with complex temperature profiles.
Area of Science:
- Condensed Matter Physics
- Thermodynamics
- Electron Transport
Background:
- Johnson-Nyquist noise arises from thermal fluctuations in resistors.
- Measuring this noise is a primary thermometry method for electron temperature.
- Existing theories are limited to Ohmic devices and do not cover hydrodynamic electron systems.
Purpose of the Study:
- To generalize the Johnson-Nyquist theorem for hydrodynamic electron systems.
- To address the need for accurate thermometry in systems where local conductivity is not applicable.
- To investigate low-frequency Johnson noise in a rectangular hydrodynamic electron system.
Main Methods:
- Theoretical analysis of low-frequency Johnson noise.
- Consideration of a rectangular geometry for hydrodynamic electron systems.
- Investigation of nonlocal viscous gradients.
Main Results:
- Johnson noise in hydrodynamic systems is geometry-dependent due to nonlocal viscous effects.
- The generalization accounts for the unique properties of hydrodynamic electrons.
- Ignoring geometric corrections results in a maximum error of 40% compared to the Ohmic approximation.
Conclusions:
- The study provides a necessary theoretical framework for Johnson noise thermometry in hydrodynamic electron systems.
- This work enables more accurate electron temperature measurements in novel electronic devices.
- The findings highlight the importance of geometric considerations in hydrodynamic transport phenomena.
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