ارتجاف الفضاء الفارغ سريع

الملخص الأصلي

كما كتبه المؤلفون، بالإنجليزية arXiv:2606.16296

We study the real-time linear response of gravitational waves in a time-dependent resonant scalar field in a Minkowski background. In the Schwinger-Keldysh formalism, we develop an adiabatic regularization scheme for unequal-time correlation functions and use it to extract the ultraviolet structure of the one-loop response. The leading divergence reproduces the familiar $$\Box^2 h_{ij}$$ structure, whereas the time-dependent background induces additional local divergences proportional to $$\Box h_{ij}$$, $$\partial_0 h_{ij}$$, and $$h_{ij}$$. These are renormalized by local counterterms associated with the Weyl-squared term, a time-dependent Ricci-scalar term, and a time-dependent cosmological constant. We also compare the renormalization of the linear response with that of the tadpole stress tensor and find a mismatch beyond leading adiabatic order in the present toy model. By considering a covariant completion of the resonance, we further argue that this mismatch is tied to the off-shell nature of the fixed background, and is expected to disappear once the background is treated on shell.