利用单极矩减除从慢滚多场背景发生的隧穿
Tunneling from a Slowly Rolling Multifield Background Using Tadpole Subtraction
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中文总结 AI 辅助
该研究结合单极矩减除与绝热展开构建慢滚多场背景下的隧穿问题，针对慢滚暴胀场景分析隧穿指数的演化规律，揭示切向曲率消失时隧穿指数的非解析极限特性。
中文摘要 AI 辅助
我们研究具有缓慢演化均匀背景的标量场理论中的半经典隧穿问题。我们通过结合单极矩减除（tadpole subtraction）与绝热展开来构建该问题：前者将滚动系统映射为瞬时多场隧穿问题，后者则系统地追踪背景的缓慢演化。该构建对慢滚暴胀期间的隧穿尤为有用，此时隧穿方向可与滚动的暴胀子方向垂直。对于固定壳上几何上的时间反射对称 bounce，我们证明实隧穿指数不会受到滚动速度的线性直接修正。不过，隧穿率会沿滚动轨迹漂移，因为冻结的单极矩减除势会发生演化。我们还发现，当切向曲率消失时，指数趋近于有限但非解析的极限，这表明弱快子型切向方向可产生同量级的指数。
英文摘要
We study semiclassical tunneling in scalar field theories with slowly evolving homogeneous backgrounds. We formulate the problem by combining tadpole subtraction with an adiabatic expansion: the former maps the rolling system to an instantaneous multi-field tunneling problem, while the latter systematically tracks the slow evolution of the background. This formulation is particularly useful for tunneling during slow-roll inflation, where the tunneling direction may be transverse to the rolling inflaton direction. For a time-reflection-symmetric bounce on a fixed on-shell geometry, we show that the real tunneling exponent receives no direct correction linear in the rolling velocity. The tunneling rate nevertheless drifts along the rolling trajectory because the frozen tadpole-subtracted potential evolves. We also find that the exponent approaches a finite but nonanalytic limit as the tangential curvature vanishes, suggesting that a weakly tachyonic tangential direction can yield an exponent of the same order.
