标题： 密集核物质中的体积粘滞系数 显示英文标题

标题： Bulk Viscosity in Dense Nuclear Matter

摘要： 在本章中，我描述了体积粘度作为一个一般概念，然后专注于致密物质中存在的体积粘度，这些物质存在于致密天体中。 虽然本综述重点在于中子星合并条件下的体积粘度，但我介绍了致密物质中体积粘度研究的历史，从其在中子星径向振荡中的阻尼作用到其在中子星合并中的当前应用。 本章的大部分内容是计算从通用中子星-质子-电子（$npe$）物质中的Urca过程得到的体积粘度，以及在包含μ子（$npe\mu$物质）的致密物质中的体积粘度。 在这些计算中，我做了几个近似，以保持对概念的聚焦。 文献中存在更精确的计算，我将读者引向这些文献。 我试图阐明的一个概念是流体元素在整个振荡中的热力学行为，以及这如何导致体积粘性耗散。 最后，我讨论了最近关于弱相互作用和体积粘度在中子星合并中的作用的研究。 显示英文摘要

摘要： In this chapter, I describe bulk viscosity as a general concept, and then focus on bulk viscosity in the dense matter present in compact objects. While this review is focused on bulk viscosity in the conditions present in neutron star mergers, I present a history of bulk viscosity research in dense matter, from its role in damping radial oscillations in neutron stars through its current applications in neutron star mergers. The majority of the chapter consists of calculations of the bulk viscosity from Urca processes in generic neutron-proton-electron ($npe$) matter, and then in dense matter containing muons ($npe\mu$ matter) as well. I make several approximations in these calculations to keep the focus on the concepts. More precise calculations exist in the literature, to which I refer the reader. One concept I attempt to elucidate is the thermodynamic behavior of a fluid element throughout an oscillation and how that leads to bulk-viscous dissipation. I conclude with a discussion of the recent research into the role of weak interactions and bulk viscosity in neutron star mergers.