论文标题
显然是关于相互作用真空的扰动理论
Manifestly Causal In-In Perturbation Theory about the Interacting Vacuum
论文作者
论文摘要
扰动理论是宇宙学和非平衡物理学的重要工具。 Here, we reconcile an apparent conflict between two of its important aspects with particular relevance to De Sitter/inflationary contexts: (i) the need to slightly deform unitary time evolution with an i*epsilon prescription that projects the free ("Bunch-Davies") vacuum onto the interacting vacuum and renders vertex integrals well-defined, and (ii) Weinberg's "nested commutator" reformulation of in-in perturbation假设确切的单位性，使在本地运营商的期望值内表现出因果关系的限制的理论。我们表明，经过修改的i*epsilon处方保持（ii）的派生为基础的确切单位性，而非试图与（i）对所有扰动理论的顺序一致。
In-In perturbation theory is a vital tool for cosmology and nonequilibrium physics. Here, we reconcile an apparent conflict between two of its important aspects with particular relevance to De Sitter/inflationary contexts: (i) the need to slightly deform unitary time evolution with an i*epsilon prescription that projects the free ("Bunch-Davies") vacuum onto the interacting vacuum and renders vertex integrals well-defined, and (ii) Weinberg's "nested commutator" reformulation of in-in perturbation theory which makes manifest the constraints of causality within expectation values of local operators, assuming exact unitarity. We show that a modified i*epsilon prescription maintains the exact unitarity on which the derivation of (ii) rests, while nontrivially agreeing with (i) to all orders of perturbation theory.
