In this paper, the translation invariant massless Nelson model with ultraviolet cutoff is investigated. It is proven that the fiber operators does not have a ground state if the interaction is not infrared regular. Similar results have been obtained by other authors under severe assumptions on the regularity of the mass shell. The method introduced in this paper works under very general conditions and relies only on rotation invariance of the mass shell, non-degeneracy of ground states and the HVZ theorem.

中文翻译：

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平移不变的无质量纳尔逊模型中基态的缺乏

本文研究了具有紫外线截止的平移不变无质量尼尔森模型。事实证明，如果相互作用不是红外规律的，光纤操作员就不会具有基态。在严格假设质量壳的规则的前提下，其他作者也获得了类似的结果。本文介绍的方法在非常普通的条件下工作，并且仅取决于质量壳的旋转不变性，基态的非简并性和HVZ定理。