Amendola Luca
INAF/Osservatorio Astronomico di Roma, Viale Frascati 33, 00040 Monteporzio Catone, Rome, Italy.
Phys Rev Lett. 2004 Oct 29;93(18):181102. doi: 10.1103/PhysRevLett.93.181102.
Scalar field models with nonstandard kinetic terms have been proposed in the context of k inflation, of Born-Infeld Lagrangians, of phantom energy and, more in general, of low-energy string theory. In general, scalar fields are expected to couple to matter inducing a new interaction. In this Letter I derive the cosmological perturbation equations and the Yukawa correction to gravity for such general models. I find three interesting results: first, when the field behaves as phantom energy (equation of state less than -1), then the coupling strength is negative, inducing a long-range repulsive force; second, the dark-energy field might cluster on astrophysical scales; third, applying the formalism to a Brans-Dicke theory with a general kinetic term it is shown that its Newtonian effects depend on a single parameter that generalizes the Brans-Dicke constant.
具有非标准动能项的标量场模型已在暴胀、玻恩-因费尔德拉格朗日量、幻能以及更一般的低能弦理论的背景下被提出。一般而言，标量场预计会与物质耦合从而引发一种新的相互作用。在这篇快报中，我推导了此类一般模型的宇宙学微扰方程以及对引力的汤川修正。我发现了三个有趣的结果：第一，当场表现为幻能（状态方程小于 -1）时，耦合强度为负，会引发长程排斥力；第二，暗能量场可能在天体物理尺度上聚集；第三，将该形式体系应用于具有一般动能项的布兰斯 - 迪克理论时表明，其牛顿效应取决于一个推广了布兰斯 - 迪克常数的单一参数。
