论文标题
二次重力重力扰动的非平凡时间晶体状基态
Non-trivial time crystal-like ground state for gravitational perturbation in quadratic gravity
论文作者
论文摘要
我们考虑涉及二次曲率校正的重力理论的最大对称背景的重力扰动。这导致了标准横向，无可纹理重力模式和额外标量自由度的脱钩模型。后者的演变受拉格朗日的约束，该拉格朗日依赖于较高的衍生术语，该术语是从动作中的二次曲率校正继承的。事实证明，引力理论的稳定性使标量部门可以在可能在空间或时间上维持周期性不均匀形式的可能最低能量状态（或基态）之间进行选择。后者在时间翻译中具有限制形式的不变性形式，可能是时间晶体的变体形式。这种新型基态的存在，描绘了时间晶体，仅与动作中较高的曲率项的存在有关。特别是，这种非平凡的冷凝物样基态通过引入理论中的基本尺度来描述时空织物本身。还讨论了可能的含义。
We consider gravitational perturbation around maximally symmetric background of a theory of gravity involving quadratic curvature correction. This leads to a decoupled model of the standard transverse, traceless graviton mode and an additional scalar degree of freedom. Evolution of the latter is governed by a Lagrangian, which depends on higher derivative terms, inherited from the quadratic curvature correction in the action. It turns out that stability of the gravitational theory allows the scalar sector to choose between possible lowest energy states (or, ground states), that can sustain periodic form of inhomogeneity, either in space or in time. The latter, with a restricted form of invariance in time translation, is possibly a variant form of the time crystal. Existence of this novel ground state, depicting a time crystal, is solely related to the presence of higher curvature terms in the action. In particular, this non-trivial condensate-like ground state describe the spacetime fabric itself by introducing fundamental scales in the theory. Possible implications are also discussed.
