States of Low Energy (SLE) are exact Hadamard states defined on arbitrary Friedmann-Lemaitre spacetimes. They are constructed from a fiducial state by minimizing the Hamiltonian's expectation value after averaging with a temporal window function. We show the SLE to be expressible solely in terms of the (state independent) commutator function. They also admit a convergent series expansion in powers of the spatial momentum, both for massive and for massless theories. In the massless case the leading infrared behavior is found to be Minkowski-like for all scale factors. This provides a new cure for the infrared divergences in Friedmann-Lemaitre spacetimes with accelerated expansion. In consequence, massless SLE are viable candidates for pre-inflationary vacua and in a soluble model are shown to entail a qualitatively correct primordial power spectrum.

中文翻译：

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低能态的额外特性

低能态 (SLE) 是在任意弗里德曼-勒梅特时空上定义的精确哈达玛态。它们是通过在使用时间窗口函数平均后最小化哈密顿量的期望值而从基准状态构建的。我们展示了 SLE 仅根据（状态无关的）换向器函数可以表达。他们还承认空间动量的幂的收敛级数扩展，无论对于有质量的理论还是无质量的理论。在无质量的情况下，发现领先的红外行为对于所有比例因子都是类似 Minkowski 的。这为弗里德曼-勒梅特时空加速膨胀的红外发散提供了新的解决方法。结果，