发表机构
State Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences; University of Chinese Academy of Sciences; CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences; School of Physical Sciences, University of Chinese Academy of Sciences; School of Physics, Henan Normal University（中国科学院高能物理研究所粒子天体物理国家重点实验室; 中国科学院大学; 中国科学院理论物理研究所理论物理重点实验室; 中国科学院大学物理科学学院; 河南师范大学物理学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出一种新机制：多个非对齐对称性破缺源的微分热演化旋转pNGB有效真空方向，驱动其从静止最小处运动，并在I型跷跷板机制中实现，影响自发轻子生成。
AI 中文摘要
早期宇宙中轻标量场的相干运动通常归因于初始位移、原始速度或预设的温度相关势。我们识别出一种独特的微观机制，其中多个非对齐对称性破缺源的微分热演化会旋转赝南布-戈德斯通玻色子（pNGB）的有效真空方向，从而从初始静止的最小值驱动运动。该机制在I型跷跷板机制的马约拉纳扇区中实现，其中具有分离热阈值的重中微子提供了所需的微分热演化。对于一个代表性基准，热源方向旋转了$|\Delta\theta_T|\simeq0.76$弧度，并将马约拉纳子驱动至峰值速度$|\dot\theta|/H\simeq0.62$，而场以亚毫弧度精度跟踪移动的最小值。这确立了pNGB运动的微观有限温度起源，对自发轻子生成以及更普遍地，对任何具有多个非对齐且随温度不同演化的对称性破缺源的系统具有重要意义。
英文摘要
Coherent motion of light scalar fields in the early Universe is typically attributed to an initial displacement, a primordial velocity, or a prescribed temperature-dependent potential. We identify a distinct microscopic mechanism in which differential thermal evolution of multiple non-aligned symmetry-breaking sources rotates the effective vacuum direction of a pseudo-Nambu--Goldstone boson (pNGB), driving motion from an initially stationary minimum. The mechanism is realized in the Majoron sector of a Type-I seesaw mechanism, where heavy neutrinos with separated thermal thresholds supply the required differential thermal evolution. For a representative benchmark, the thermal source direction rotates by $|Δθ_T|\simeq0.76$~rad and drives the Majoron to a peak velocity $|\dotθ|/H\simeq0.62$, while the field tracks the moving minimum to sub-milliradian accuracy. This establishes a microscopic finite-temperature origin for pNGB motion, with implications for spontaneous leptogenesis and, more generally, for any system with multiple non-aligned symmetry-breaking sources that evolve differently with temperature.
Comments12 pages, 5 figures
