报告人：杨丰维，佛罗里达大学，博士后

主持人：夏力钢 老师

时间：2025年7月8日，星期二上午10:00

地点：物理楼  233  会议室

报告摘要：

The cosmic string can be superconducting, with fermionic or bosonic charged carriers propagating along the string. Fermionic superconducting strings emerge by introducing fermions that couple to the complex scalar field that constitutes the string. The fermion zero modes are bounded to the string as required by the index theorem. The Fermi pressure provided by fermion zero modes counterbalances the string weight, giving a stable string loop configuration, known as a vorton. The stability of vorton remains an open question. For example, the loop shrinkage may overshoot zero modes, the maximal Fermi energy of zero modes may not be large enough to avoid zero modes energetically jumping off of the string, the calculations of zero-mode decay rate are not consistent in the literature, and so on. In this talk, I will address these stability problems. Since the vorton stability depends on string dynamics (including string loop contraction and radiation), zero-mode decay, quantum tunneling, and scattering processes, I will tackle these problems at both classical and quantum levels. Our results show that the vorton can be cosmologically stable and thus it is intriguing to consider vorton dark matter.

报告人简介：Dr. Fengwei Yang is a postdoctoral associate in the Department of Physics at the University of Florida. He received his B.S. in Astronomy from Nanjing University in 2017 and completed his Ph.D. in Physics at the University of Utah in 2023. His research lies at the intersection of cosmology, gravitational wave (GW) physics, and beyond-the-Standard-Model (BSM) physics, with a particular focus on early-universe phenomena that offer insight into energy scales inaccessible to current colliders. His recent work centers on cosmic strings, encompassing model building, analytical studies, and data analysis using LIGO–Virgo observations. In addition, he has investigated the direct detection of BSM particles through precision experiments and explored astrophysical signatures of new physics. Dr. Yang integrates data from a range of sources—including laser interferometers, telescopes, and table-top experiments—to advance the search for fundamental physics beyond the Standard Model.