- #1
snatchingthepi
- 148
- 38
- TL;DR Summary
- There's a step from one line to another that isn't clear to me.
If anyone could help me understand how Peebles gets from line one of the autocorrelation to the second line, I'd be most grateful. I don't understand what identity or property is being used to go from a product in the expectation value to a sum in the expectation value.