极化物质中中子自旋旋转对挠率与非度量性的约束
Torsion and Nonmetricity Constraints From Neutron Spin Rotation in Polarized Matter
- Indiana University（印第安纳大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究应用有效场论方法表征粒子算符与时空挠率、非度量性的耦合，利用补偿铁氧体的中子自旋旋转数据，首次对相关物质内组合施加约束。
AI中文摘要：
许多修正引力框架采用非黎曼联络自由度，包括挠率（torsion）和非度量性（nonmetricity）。在爱因斯坦-嘉当型理论中，挠率与自旋密度相关，而更广义的度量-仿射框架可通过对物质内挠率与非度量性背景的唯象学搜索开展研究。本研究应用有效场论方法，表征电子与中子算符至质量维度6的时空挠率和非度量性的一般耦合，预测在电子背景下的新型中子极化信号。利用补偿铁氧体内部极化电子集合的中子自旋旋转数据，首次对轴向对称、方向依赖的物质内挠率与非度量性组合施加约束。
英文摘要：
Many modified-gravity frameworks employ non-Riemannian connection degrees of freedom, including torsion and nonmetricity. In Einstein-Cartan-type theories, torsion is associated with spin density, while more general metric-affine frameworks can be investigated through phenomenological searches for in-matter torsion and nonmetricity backgrounds. This work applies an effective field theory approach to characterize general couplings of electron and neutron operators to spacetime torsion and nonmetricity up to mass dimension six, predicting novel neutron-polarization signatures in the presence of an electron background. Neutron spin-rotation data from a polarized-electron ensemble inside a compensated ferrimagnet are used to constrain for the first time axially symmetric, direction-dependent in-matter torsion and nonmetricity combinations.
