IAS Program on Particle Theory:- Is Genesis Possible in the Framework of Horndeski Gravity?
In scalar-tensor Horndeski theories, nonsingular cosmological models—Bounce and Genesis—are problematic because of potential ghost and/or gradient instabilities. One way to get around this obstacle is to send the effective Planck mass to zero in the asymptotic past (“strong gravity in the past”). One may suspect that this feature is a signal of a strong coupling problem at early times. However, the classical treatment of the cosmological background is legitimate, provided that the strong coupling energy scale remains at all times much higher than the scale associated with the classical evolution. After that observation the research team and the speaker construct a novel model of Horndeski Genesis with strong gravity in the past. Within this model they show that the correct spectra of cosmological perturbations may be generated during the Genesis epoch. After that they discuss the tension between the experimental requirements for scalar spectrum index and the requirement of validity of the classical description. Nevertheless, they show that it is truly possible to obtain red-tilted spectrum and simultaneously generate perturbations in a controllable way, i.e. in the regime where the background evolution and perturbations are legitimately described within classical field theory and weakly coupled quantum theory, respectively.
時間：2024.12.11(三) 14:00~15:00
地點：香港科技大學 李兆基校園 盧家驄薈萃樓* 高研院2042室
講者：Dr. Pavel PETROV Павел (Institute for Basic Science(IBS), South Korea)
語言：英語
免費講座。座位先到先得
【此屬轉載信息，以主事單位發布為準】
*Lo Ka Chung Building, Lee Shau Kee Campus
**기초과학연구원
此活動由香港科技大學 賽馬會高等研究院主辦。
https://ias.hkust.edu.hk/events/is-genesis-possible-in-the-framework-of-horndeski-gravity
