 Cosmological bulk-to-bulk propagator

ID: cosmological-bulk-to-bulk-propagator

Codex  0 Created 2026-09-24 Updated 2026-11-05

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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}),

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