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Fabrication and Characterization of High-Q Silicon Nitride Membrane Resonators
Published on: August 8, 2025
Nonequilibrium steady-state fluctuations in actively cooled resonators.
M Bonaldi1, L Conti, P De Gregorio
1Istituto di Fotonica e Nanotecnologie, CNR-Fondazione Bruno Kessler, 38100 Povo, Trento, Italy. bonaldi@science.unitn.it
Physical Review Letters
|August 8, 2009
Summary
We studied heat and work fluctuations in the AURIGA gravitational wave detector. Experimental results match our Langevin model, showing how feedback cooling creates a nonequilibrium state.
Area of Science:
- Thermodynamics
- Statistical Mechanics
- Experimental Physics
Background:
- Gravitational wave detectors like AURIGA can be modeled as macroscopic oscillators.
- Understanding fluctuations is crucial for interpreting detector performance and fundamental physics.
- Active feedback cooling is used to enhance detector sensitivity.
Purpose of the Study:
- To analyze heat and work fluctuations in the AURIGA gravitational wave detector.
- To model the detector as an electromechanical oscillator interacting with a thermostat and feedback system.
- To investigate the nonequilibrium steady state induced by feedback cooling.
Main Methods:
- Modeling the AURIGA detector as a macroscopic electromechanical oscillator.
- Applying a Langevin system approach to analyze stochastic fluctuations.
- Comparing experimental measurements of fluctuations with theoretical predictions.
Main Results:
- Experimental fluctuations in AURIGA align with the theoretical Langevin system analysis.
- Feedback cooling drives the oscillator to a steady state, mimicking a viscous force.
- The asymmetry in heat fluctuations quantifies the system's departure from equilibrium.
Conclusions:
- The study validates the Langevin model for describing fluctuations in feedback-cooled systems.
- Feedback cooling in AURIGA creates a measurable nonequilibrium steady state.
- This work provides statistical mechanics insights into active cooling in sensitive detectors.
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