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arXiv 1503.06768gr-qcastro-ph.CO
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球对称时空中的自调谐标量场

Self Tuning Scalar Fields in Spherically Symmetric Spacetimes

Stephen Appleby

摘要:

我们寻找自调谐解决方案的爱因斯坦-标量场方程的最简单的一类“Fab-Four”模型与恒定的潜力。我们首先回顾的条件下,自调谐发生在宇宙时空,并通过引入一个小的修改,原来的理论-引入第二和第三Galileon条款-显示如何可以获得德西特状态的膨胀率是独立的真空能量。然后,我们考虑是否同样的自调谐机制可以持续在一个球对称的非均匀时空。我们表明,有没有渐近平坦的解决方案,在真空能量被屏蔽的场方程,除了平凡的(闵可夫斯基空间)。然后,我们考虑的可能性,构建Schwarzschild德西特时空的修改Fab四加Galileon理论。我们认为,唯一的模型,可以成功地屏蔽真空能量在FLRW和史瓦西德西特时空是一个包含“约翰”$\sim G^μ{}_ν \partial_μϕ\partial^νϕ$和一个典型的动力学项$\sim \partial_αϕ\partial^αϕ$。这种行为首次在(Babichev & Charmousis,2013)中观察到。屏蔽机制要求“真空”中的标量场方程具有冗余性,但在非均匀时空中,“保罗”项是不成立的。

英文摘要:

We search for self tuning solutions to the Einstein-scalar field equations for the simplest class of `Fab-Four' models with constant potentials. We first review the conditions under which self tuning occurs in a cosmological spacetime, and by introducing a small modification to the original theory - introducing the second and third Galileon terms - show how one can obtain de Sitter states where the expansion rate is independent of the vacuum energy. We then consider whether the same self tuning mechanism can persist in a spherically symmetric inhomogeneous spacetime. We show that there are no asymptotically flat solutions to the field equations in which the vacuum energy is screened, other than the trivial one (Minkowski space). We then consider the possibility of constructing Schwarzschild de Sitter spacetimes for the modified Fab Four plus Galileon theory. We argue that the only model that can successfully screen the vacuum energy in both an FLRW and Schwarzschild de Sitter spacetime is one containing `John' $\sim G^μ{}_ν \partial_μϕ\partial^νϕ$ and a canonical kinetic term $\sim \partial_αϕ\partial^αϕ$. This behaviour was first observed in (Babichev&Charmousis,2013). The screening mechanism, which requires redundancy of the scalar field equation in the `vacuum', fails for the `Paul' term in an inhomogeneous spacetime.

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