论文标题
Horndeski理论中的鬼魂的出现
Emergence of ghosts in Horndeski theory
论文作者
论文摘要
我们表明，从具有稳定的扰动的初始条件开始，Galileon标量场的演变会导致后来出现鬼魂。为了证明这一点，我们认为在固定的Minkowski背景下，具有K essence和Cubic Galileon Lagrangians的理论。构建了简单波的显式分析解决方案，其最重要的是，健康的标量自由度被证明转化为幽灵。这种转化是平稳的，而且扰动一直保持双曲线（直到苛性形式）。我们讨论了此类解决方案的幽灵与封闭因果曲线的出现之间的关系。
We show that starting from initial conditions with stable perturbations, evolution of a galileon scalar field results in the appearance of a ghost later on. To demonstrate this, we consider a theory with k-essence and cubic galileon Lagrangians on a fixed Minkowski background. Explicit analytical solutions of simple waves are constructed, on top of which a healthy scalar degree of freedom is shown to be converted onto a ghost. Such a transformation is smooth and moreover perturbations remain hyperbolic all the time (until a caustic forms). We discuss a relation between the ghost and the appearance of closed causal curves for such solutions.
