Christopher Miller Grayson, Physics Graduate Student
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Abstract: The primary motivation for this research was to explore the strong electromagnetic fields generated during heavy ion collisions. These fields are among the strongest in the natural world, with a magnetic field of approximately $|B| \approx 10^{14}\,$T and an electric field of around $|E| \approx 10^{23}\,$V/m in the collision of gold nuclei at the Relativistic Heavy Ion Collider. Understanding the conductive properties of the quark-gluon plasma (QGP) formed between the colliding ions is essential to describe these huge electromagnetic fields. To analyze the influence of QGP polarization on these fields, we developed the covariant kinetic theory detailed in this dissertation.
Dense relativistic matter-antimatter plasmas are states of matter prevalent in extreme astrophysical environments and achievable through high-energy particle collisions. This dissertation studies these plasmas by developing a covariant kinetic theory with collisional scattering, delving into the linear responses of dense electron-positron and quark-gluon plasmas to electromagnetic fields, elucidating some underlying mechanisms governing their behavior.
We begin by solving the kinetic theory for plasma response, considering spatial and temporal dispersion, and focusing on electron-positron plasmas. We then discuss how the covariant polarization tensor, incorporating collisional damping, influences the self-consistent electromagnetic fields within the medium, particularly highlighting the dynamics and damping within the plasma.
We then extend our investigation to the quark-gluon plasma, emphasizing the magnetic field response during heavy ion collisions. By examining the ultrarelativistic electromagnetic polarization tensor using different conductivity models, we find that the conductivity evaluated on the light-cone accurately describes the evolution of magnetic fields in the QGP during heavy ion collisions. We use this insight to provide an analytic formula predicting the freeze-out magnetic field in the QGP, possibly allowing for the experimental determination of QGP's electromagnetic conductivity.
Next, we address the effects of damped-dynamic screening in electron-positron plasmas during the Big Bang Nucleosynthesis (BBN), demonstrating how screening influences internuclear potentials and nuclear fusion reaction rates, thereby impacting the synthesis of light elements in the early Universe. We find an analytic formula predicting the nuclear reaction rate enhancement during BBN due to damped-dynamic screening. Due to the significant damping and temperature during BBN, this enhancement represents a small correction ($10^{-5}$) to the usual screening enhancement.
Zoom information: https://arizona.zoom.us/my/chrisgray1044