在非最小耦合矢量引力中规避宇宙学强耦合
Evading Cosmological Strong Coupling in Non-minimally Coupled Vector Gravity
浏览论文内容
中文总结 AI 辅助
研究非最小耦合矢量引力中宇宙学强耦合问题，通过额外导数相互作用恢复标量微扰非简并二次动力学，消除相关强耦合特征，还发现非均匀极限及稳定德西特不动点等情况。
中文摘要 AI 辅助
最近对具有非最小曲率耦合的普罗卡理论的分析发现了一个额外的标量自由度，其传播速度恒为零，即\(c_s^2 = 0\)，这表明存在一个与尺度相关的强耦合问题。在本《快报》中，我们表明额外的导数相互作用可以消除这种零速度简并，并恢复标量微扰的非简并二次动力学。在参数空间的一个开放区域中，标量动力学矩阵是正定的，高频传播速度是实的且为正。在二次项阶，这消除了与\(c_s^2 = 0\)模式相关的强耦合的特定特征。我们还发现，当时间矢量凝聚态趋近于零时存在一个非均匀极限：在固定的非零\(A_0\)下，形式上的极紫外区域会出现一个鬼态，而精确消失凝聚态分支的动力学结构则不同。随着\(A_0\to0\)，出现这个鬼态的动量尺度被推向越来越高的值。这个鬼态尺度最终是否高于有效场论截断取决于对有效场论截断的独立确定。最后，我们确定了一个\(A_0\neq0\)的稳定德西特不动点，其周围有一个有限区域，在该区域中标量无鬼态和高频稳定性条件仍然满足。
英文摘要
Recent analyses of Proca theories with non-minimal curvature couplings have uncovered an additional scalar degree of freedom with an identically vanishing propagation speed, $c_s^2=0$, signaling a scale-dependent strong-coupling problem. In this {\it Letter}, we show that an additional derivative interaction can lift this zero-speed degeneracy and restore a non-degenerate quadratic dynamics for the scalar perturbations. In an open region of parameter space, the scalar kinetic matrix is positive definite and the high-frequency propagation speeds are real and positive. At quadratic order, this removes the specific signature of strong coupling associated with the $c_s^2=0$ mode. We also uncover a non-uniform limit as the temporal vector condensate approaches zero: at fixed nonzero $A_0$, the formal extreme-ultraviolet regime develops a ghost, while the kinetic structure of the exactly vanishing-condensate branch is different. The momentum scale at which this ghost appears is pushed toward increasingly high values as $A_0\to0$. Whether the ghost scale ultimately lies above the EFT cutoff depends on an independent determination of the EFT cutoff. Finally, we identify a stable de Sitter fixed point with $A_0\neq0$, surrounded by a finite region in which the scalar no-ghost and high-frequency stability conditions remain satisfied.
