Experimental test of the fluctuation theorem for a driven two-level system with time-dependent rates

Area of Science:

• Quantum physics
• Non-equilibrium statistical mechanics
• Diamond defect centers

Background:

• Fluctuation theorems describe the statistical properties of work and entropy in non-equilibrium systems.
• Nonthermal noise in quantum systems presents unique statistical behaviors.
• Diamond defect centers are promising quantum systems for studying fundamental physics.

Purpose of the Study:

• To experimentally realize a system obeying a fluctuation theorem with nonthermal noise.
• To investigate the statistical distribution of fluctuations in such a system.
• To compare the observed behavior with theoretical predictions for thermal and nonthermal noise.

Main Methods:

• Utilizing a single defect center in diamond as a quantum system.
• Periodically exciting the defect center with a laser.
• Analyzing the resulting noise and fluctuation distributions.
• Performing numerical calculations to verify experimental findings.

Main Results:

• The diamond defect center system successfully demonstrated a fluctuation theorem for nonthermal noise.
• The fluctuation distribution was found to be distinctly non-Gaussian.
• Numerical simulations confirmed the non-Gaussian nature of the fluctuations.
• A restricted form of the fluctuation theorem was observed for time-reversal symmetric driving protocols.

Conclusions:

• A single laser-excited diamond defect center provides a simple experimental platform for studying fluctuation theorems with nonthermal noise.
• The non-Gaussian nature of these fluctuations highlights differences from classical thermal noise systems.
• This work contributes to understanding non-equilibrium statistical mechanics in quantum systems.