Probability distribution for heat exchange in plastic deformation.

Area of Science:

• Thermodynamics
• Materials Science
• Statistical Mechanics

Background:

• Fluctuation theorems connect nonequilibrium experiments to equilibrium thermodynamics.
• Probability distribution functions (PDFs) are crucial for fluctuation theorems, but often non-Gaussian and asymmetric in small systems.
• Previous work on van Hove correlation functions yielded symmetric PDFs, hindering fluctuation theorem applications.

Purpose of the Study:

• To investigate the PDF of heat exchanged during plastic deformation of aluminum nanowires.
• To assess the applicability of fluctuation theorems to nonequilibrium processes in small systems.
• To reconcile the symmetry of van Hove correlation function PDFs with the asymmetry often observed in physical quantities.

Main Methods:

• Molecular dynamics calculations of heat exchange in aluminum nanowires.
• Analysis of the probability distribution function (PDF) of the exchanged heat.
• Calculation of a symmetry function to characterize the PDF's properties.

Main Results:

• The PDF of heat exchanged during plastic deformation is centrally Gaussian with asymmetric exponential tails.
• This distribution is consistent with fluctuation theorems.
• The symmetry function confirms the PDF's compatibility with theoretical predictions.

Conclusions:

• The PDF of heat exchanged provides a viable route for applying fluctuation theorems to nonequilibrium processes.
• This approach overcomes limitations posed by symmetric PDFs derived from correlation functions.
• Findings offer insights into thermodynamics of small systems and materials deformation.