The figure plots the average energy of a quantum mechanical oscillator (in red) for different temperatures, and compares it with the value predicted by the equipartition theorem (in black).  Made by me today (18 April 2007) using my own GPL software, and plotted using xmgrace, another GPL program.  Released by me today under the GFDL.
No machine-readable author provided. <a href="//commons.wikimedia.org/wiki/User:WillowW" title="User:WillowW">WillowW</a> assumed (based on copyright claims).
CC BY-SA 3.0
No machine-readable source provided. Own work assumed (based on copyright claims).