在暴胀期间通过间歇性违反零能条件和降低引力波传播速度产生增强的原初引力波
Generating enhanced primordial GWs during inflation with intermittent violation of NEC and diminishment of GW propagating speed
AI总结：
本文研究暴胀期间通过间歇性违反零能条件或降低引力波传播速度来增强原初引力波功率谱的两种机制，在有效场论框架下统一处理，计算了功率谱并给出NEC违反情形的模板，同时用disformal变换分析了两者的联系与差异。
摘要：
我们研究了在暴胀期间产生增强原初引力波功率谱的两种情形：违反零能条件（NEC）的情形和降低引力波传播速度 $c_T$ 的情形，其中 $c_T$ 是原初引力波的传播速度。这两种情形都可以在超越Horndeski的理论中稳定实现，因此可以在有效场论框架内统一处理。我们假设暴胀宇宙经历三个阶段，其中违反NEC或降低 $c_T$ 发生在中间阶段，由此计算了原初引力波的功率谱。针对违反NEC的情形，我们给出了功率谱的模板。我们还利用disformal变换讨论了这两种情形之间的内在联系与差异。
英文摘要：
We investigate both the null energy condition (NEC) violating scenario and the $c_T$-diminishing scenario for generating enhanced power spectrum of primordial gravitational waves (GWs) during inflation, where $c_T$ is the propagating speed of primordial GWs. Both of these two scenarios can be realized stably with theories beyond Horndeski, hence can be uniformly implemented within the framework of the effective field theory. We calculate the power spectrum of primordial GWs by assuming that the inflationary Universe undergoes three phases, where the violation of NEC or the diminishment of $c_T$ occurs in the intermediate phase. A template of the spectrum is given for the NEC-violating scenario. We also discuss the underlying relation and discrepancy between these two scenarios with a disformal transformation.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
