Experimental Test of the Differential Fluctuation Theorem and a Generalized Jarzynski Equality for Arbitrary Initial...

Area of Science:

• Thermodynamics
• Statistical Mechanics
• Nanophysics

Background:

• Nonequilibrium processes in small systems are crucial in biology, chemistry, and physics.
• Fluctuation theorems, generalizations of the second law, offer insights into these processes.
• A unified differential fluctuation theorem has been proposed but lacked experimental verification.

Purpose of the Study:

• To perform the first experimental test of the differential fluctuation theorem.
• To validate generalized thermodynamic relations for nonequilibrium processes.
• To initiate experimental studies of stochastic energetics using instantaneous velocity measurements.

Main Methods:

• Utilizing an optically levitated nanosphere as a model system.
• Conducting experiments in both underdamped and overdamped regimes.
• Measuring both spatial and velocity dynamics of the nanosphere.

Main Results:

• Experimental verification of the differential fluctuation theorem.
• Confirmation of generalized Jarzynski equality and the Hummer-Szabo relation.
• Successful instantaneous velocity measurements for stochastic energetics.

Conclusions:

• The differential fluctuation theorem is experimentally validated.
• Fundamental theorems of stochastic thermodynamics are confirmed.
• This work opens new avenues for experimental investigations in nonequilibrium statistical physics.