In this talk, we establish a systematic framework to describe the vacuum decays in a radiation-dominated FLRW universe from the Schwinger-Keldysh formalism. By splitting the phase transition field Φ into the mean field ϕ and the short-wavelength modes σ and tracing over the latter as the environment, we obtain a classical Langevin-type equation-of-motion for the mean field ϕ, where the quantum effects are encoded in a non-Markov memory kernel and a non-Gaussian noise. As a phenomenological example, we consider a polynomial potential and study the structure of the memory kernel as well as the correlation functions of the noise term. With a less restrictive scale split by allowing ϕ to carry spatial dependence, further extensions remain possible to describe the whole dynamics of cosmological first-order phase transitions via numerical simulations.

Biography

宇文子炎，2020年本科毕业于西安交通大学，2025年博士毕业于中国科学院理论物理研究所，博士期间于2024年--2025年在南非Stellenbosch大学物理系访问。自2025年至今为亚太理论物理中心（APCTP）YST博士后。研究方向为引力理论与宇宙学。在RPD，PRR，JCAP等期刊发表论文十余篇，被引200余次，并担任EPJC，CPC等杂志审稿人。目前的研究兴趣为宇宙学一阶相变现象学，原初黑洞形成机制，以及与21cm宇宙学相关的射电天文学内容。

Inviter: Shao-Jiang Wang