题 目：Fate of Z2 symmetric scalar condensates in the early Universe
报告人：艾稳元 博士后 伦敦国王学院
时 间：2023年9月8号（星期五）下午15：00
地 点：腾讯会议：490-873-418
邀请人：边立功
报告摘要：Scalar condensates are common objects in cosmology, existing in various forms (strings, domain walls, oscillating condensates). In this talk, I will discuss the evolution of Z_2 symmetric, oscillating homogeneous scalar condensates in the early Universe from first principles (non-equilibrium quantum field theory). We show that the decay of such scalar condensates cannot be complete because their decay rates always decrease faster than the Hubble parameter at sufficiently late times. This is due to either the amplitude dependence or the temperature dependence in the condensate decay rates. This incomplete decay of Z_2 scalar condensates is reminiscent of the freeze-out process of ordinary particles. Consequently, such oscillating scalar condensates make an irreducible contribution to the dark matter relic abundance unless they fragment.
报告人介绍：艾稳元，本科硕士毕业于兰州大学，2019年博士毕业于慕尼黑工业大学。此后，分别于2019年至2021年在法语鲁汶大学（UC Louvain, CP3)，2021年至今在伦敦国王学院从事博士后工作。主要研究兴趣为宇宙粒子物理学，特别是热场论和非平衡态场论在早期宇宙（比如重加热和一级相变）的应用。对其它理论问题如强CP破坏问题等也非常感兴趣。
