Cosmological cutting rules for Bogoliubov initial states
The field theoretic wavefunction in cosmological spacetimes has received much attention as a fundamental object underlying the generation of primordial perturbations in our universe. Assuming an initial Bunch-Davies state, unitary time evolution implies an infinite set of cutting rules for the wavef...
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2025-01-01
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| Series: | SciPost Physics |
| Online Access: | https://scipost.org/SciPostPhys.18.1.005 |
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| author | Diptimoy Ghosh, Enrico Pajer, Farman Ullah |
| author_facet | Diptimoy Ghosh, Enrico Pajer, Farman Ullah |
| author_sort | Diptimoy Ghosh, Enrico Pajer, Farman Ullah |
| collection | DOAJ |
| description | The field theoretic wavefunction in cosmological spacetimes has received much attention as a fundamental object underlying the generation of primordial perturbations in our universe. Assuming an initial Bunch-Davies state, unitary time evolution implies an infinite set of cutting rules for the wavefunction to all orders in perturbation theory, collectively known as the cosmological optical theorem. In this work, we generalise these results to the case of Bogoliubov initial states, accounting for both parity-even and parity-odd interactions. We confirm our findings in a few explicit examples, assuming IR-finite interactions. In these examples, we preserve scale invariance by adiabatically turning on interactions in the infinite past rather than imposing a Bogoliubov state at some finite initial time. Finally, we give a prescription for computing Bogoliubov wavefunction coefficients from the corresponding Bunch-Davies coefficients for both $n$-point contact and four-point exchange diagrams. |
| format | Article |
| id | doaj-art-37677936cf5e402096928f93af7e3b1c |
| institution | Kabale University |
| issn | 2542-4653 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | SciPost |
| record_format | Article |
| series | SciPost Physics |
| spelling | doaj-art-37677936cf5e402096928f93af7e3b1c2025-01-07T11:45:42ZengSciPostSciPost Physics2542-46532025-01-0118100510.21468/SciPostPhys.18.1.005Cosmological cutting rules for Bogoliubov initial statesDiptimoy Ghosh, Enrico Pajer, Farman UllahThe field theoretic wavefunction in cosmological spacetimes has received much attention as a fundamental object underlying the generation of primordial perturbations in our universe. Assuming an initial Bunch-Davies state, unitary time evolution implies an infinite set of cutting rules for the wavefunction to all orders in perturbation theory, collectively known as the cosmological optical theorem. In this work, we generalise these results to the case of Bogoliubov initial states, accounting for both parity-even and parity-odd interactions. We confirm our findings in a few explicit examples, assuming IR-finite interactions. In these examples, we preserve scale invariance by adiabatically turning on interactions in the infinite past rather than imposing a Bogoliubov state at some finite initial time. Finally, we give a prescription for computing Bogoliubov wavefunction coefficients from the corresponding Bunch-Davies coefficients for both $n$-point contact and four-point exchange diagrams.https://scipost.org/SciPostPhys.18.1.005 |
| spellingShingle | Diptimoy Ghosh, Enrico Pajer, Farman Ullah Cosmological cutting rules for Bogoliubov initial states SciPost Physics |
| title | Cosmological cutting rules for Bogoliubov initial states |
| title_full | Cosmological cutting rules for Bogoliubov initial states |
| title_fullStr | Cosmological cutting rules for Bogoliubov initial states |
| title_full_unstemmed | Cosmological cutting rules for Bogoliubov initial states |
| title_short | Cosmological cutting rules for Bogoliubov initial states |
| title_sort | cosmological cutting rules for bogoliubov initial states |
| url | https://scipost.org/SciPostPhys.18.1.005 |
| work_keys_str_mv | AT diptimoyghoshenricopajerfarmanullah cosmologicalcuttingrulesforbogoliubovinitialstates |