ICTS:30647

Video URL

Primary and scalar-induced, secondary gravitational waves from the early universe

Primary and scalar-induced, secondary gravitational waves from the early universe

(2024). Primary and scalar-induced, secondary gravitational waves from the early universe. SciVideos. https://youtube.com/live/W4Io1HQm83E

Primary and scalar-induced, secondary gravitational waves from the early universe. SciVideos, Dec. 31, 2024, https://youtube.com/live/W4Io1HQm83E 

          @misc{ scivideos_ICTS:30647,
            doi = {},
            url = {https://youtube.com/live/W4Io1HQm83E},
            author = {},
            keywords = {},
            language = {en},
            title = {Primary and scalar-induced, secondary gravitational waves from the early universe},
            publisher = {},
            year = {2024},
            month = {dec},
            note = {ICTS:30647 see, \url{https://scivideos.org/index.php/icts-tifr/30647}}
          }
L Sriramkumar
Talk numberICTS:30647
Source RepositoryICTS-TIFR
Collection

Abstract

In these two lectures, I shall discuss the generation of primary gravitational waves (GWs) during inflation and secondary GWs sourced by enhanced scalar perturbations during the epoch of radiation domination. In the first lecture, after a quick introduction to inflation and reheating, I shall describe the origin of GWs from the quantum vacuum during inflation and also discuss their evolution post inflation. I shall begin the second lecture by describing the generation of scalar spectra with enhanced power on small scales due to a brief phase of ultra slow roll during the later stages of inflation. Thereafter, I shall outline the manner in which the enhanced scalar power on small scales can generate secondary GWs of strengths comparable to the sensitivities of the ongoing and forthcoming GW observatories. I shall conclude by highlighting that the scalar-induced, secondary GWs generated during reheating can possibly explain the recent observations by the pulsar timing arrays that suggest a stochastic background of GWs.