 Cosmological bulk-to-bulk propagator

ID: cosmological-bulk-to-bulk-propagator

For a free mode

f (k, η)

, the right-right bulk propagator is time ordered,

G_{RR} (η_{1}, η_{2}; k) = θ (η_{1} - η_{2}) f (η_{1}) f^{*} (η_{2}) + θ (η_{2} - η_{1}) f (η_{2}) f^{*} (η_{1}),

 New to topics? Read the docs here!