发表机构
The University of Tokyo; RIKEN Nishina Center; Quark Nuclear Science Institute, The University of Tokyo（东京大学; 理化学研究所西村中心; 东京大学夸克核科学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过类比超冷费米气体的BEC-BCS交叉，研究强子-夸克交叉中的三重涨落机制，解释重子动量壳层和声速峰值，并联系唯象夸克物态方程。
AI 中文摘要
在中子星和稠密量子色动力学（QCD）物理中，理解重子物质在高密度下如何演化为夸克物质至关重要。连续的强子-夸克交叉是最有吸引力的候选机制之一，因为它可以调和核密度附近相对软的物态方程与支撑大质量中子星所需的快速硬化之间的矛盾。近期中子星观测推动了在中间密度区域快速硬化的物态方程，而夸克物质描述在该区域呈现出壳层状的重子动量分布。本文回顾了我们近期关于这些现象的微观描述和解释的工作，通过类比超冷费米气体和双色QCD中的玻色-爱因斯坦凝聚（BEC）到巴丁-库珀-施里弗（BCS）交叉展开讨论。由于配对涨落在BEC-BCS交叉中起着关键作用，我们讨论了其三体对应物——即与强子-夸克交叉中重子形成相关的三重涨落的作用。通过三重涨落的相移表示，三体束缚态极点与散射连续谱之间的相互作用抑制了低动量重子占据，产生了重子动量壳层，并降低了密度敏感性，从而在声速中产生峰值。我们回顾了在一维三分量费米气体中该机制的演示、其相对论推广及其与唯象夸克物态方程的联系。
英文摘要
In neutron-star and dense quantum chromodynamics (QCD) physics, it is important to understand how baryonic matter evolves into quark matter at high density. A continuous hadron--quark crossover is one of the most attractive candidates because it can reconcile the comparatively soft equation of state around nuclear density with the rapid stiffening required to support massive neutron stars. Recent neutron-star observations motivate equations of state that stiffen rapidly across the intermediate-density regime, while quarkyonic-matter descriptions feature a shell-like baryon momentum distribution there. In this paper, we review our recent work on the microscopic description and interpretation of these phenomena by drawing an analogy with the Bose--Einstein condensate (BEC) to Bardeen--Cooper--Schrieffer (BCS) crossover in ultracold Fermi gases and two-color QCD. As pairing fluctuations play a crucial role in the BEC--BCS crossover, we discuss the role of its three-body counterpart, that is, tripling fluctuations associated with baryon formation in the hadron--quark crossover. In terms of a phase-shift representation of tripling fluctuations, the interplay between a three-body bound-state pole and the scattering continuum suppresses low-momentum baryonic occupation, generates a baryonic momentum shell, and reduces the density susceptibility, thereby producing a peak in the speed of sound. We review the demonstration of this mechanism in a one-dimensional three-component Fermi gas, its relativistic extension, and its connection to phenomenological quarkyonic equations of state.
Comments10 pages, 3 figures, Review prepared for the QCS2026 proceedings; submitted to Journal of Subatomic Particles and Cosmology
