Gibbs probability density

The Gibbs probability density in a classical Klein-Gordon field was an equation marked on the blackboard by Coal Hill physics teacher Miss Quill. She asked the class to simplify the equation. Tanya was the only one in the class to recognise it for what it was.

Tanya later helped Ram Singh solve the equation over a Skype call, and he was successful. (TV: For Tonight We Might Die)