4 papers
Multi-soft theorems for cosmological correlators: Background wave method for scalars & gravitons
Farman Ullah
Cosmological soft theorems (or consistency relations) provide a powerful probe for the physics of inflation. These relations rely on minimal assumptions and hold very generally. Co…
Massive Exchange and the Sign of the Equilateral Bispectrum
Diptimoy Ghosh, Suvashis Maity, Farman Ullah
We study the inflationary bispectrum generated by the tree-level exchange of a massive hidden-sector scalar during inflation. When the interaction between the inflaton and the hidd…
Singularities in Cosmological Loop Correlators
Supritha Bhowmick, Mang Hei Gordon Lee, Diptimoy Ghosh +1
In this work we perform a systematic study of the singularity structure of inflationary correlations at 1-loop. We explicitly compute a few diagrams and find a pattern emerging in…
Cosmological cutting rules for Bogoliubov initial states: any mass and spin
Diptimoy Ghosh, Farman Ullah
The cosmological optical theorem and the cutting rules are well-known consequences of unitary time evolution in cosmology. The earlier works showed that assuming a Bunch-Davies ini…