# What does the average mean in Jarzynski equality?

Jarzynski equality: $$\left<\exp(-\beta W)\right> = \exp(-\beta \Delta F)$$ In Jarzynski's paper on Physics Review Letter on arxiv, he just said canonical ensemble average, but he mean which system's canonical ensemble? And the Jarzynski equality is confirmed by experiment, how do we comprehend ensemble distribution in real life?

This results in a probability distribution over $$W$$. You can average over that distribution, or equivalently average over an infinite number of trials. This is the average in the equality.
• Does the trails just have the same parameter change or the same parameter change process? ( that is, just $\lambda: A\to B$ or with the same $\lambda(t)$ function) Mar 30 '19 at 2:49