arXiv 1108.08762011-08astro-ph.COgr-qchep-phhep-th

标量场暗能量参数化

Scalar Field Dark Energy Parametrization

Axel de la Macorra

备注：: 10 Pages, 9 figures

摘要：

我们提出了一种新的基于标量场动力学的暗能量参数化。我们使用状态方程$w=(x-1)/(x+1)$，其中$x=E_k/V$是动能$E_k=\dotϕ^2/2$和势能$V$的比值。的EQ。给出了$x=(L/6)(V/3H^2)$和一个解$x=([1+2 L/3(1+y)]^{1/2}-1)(1+y)/2$，其中$y\equiv \rm/V$和$L\equiv (V'/V)^2 (1+q)^2,\, q\equiv\ddot\p/V'$。由于宇宙目前正在加速，我们使用慢滚近似，在这种情况下，我们有$|q|\ll 1$和$L\simeq (V'/V)^2$。然而，$L$的推导是精确的，没有近似。通过选择一个适当的对$L$，我们得到了广泛的一类行为的暗能量的演变，而不需要指定潜在的$V$。事实上，$w$可以作为红移的函数增长，然后减少，或者相反，对于任何只有引力相互作用的正则标量场，它是$-1\leq w\leq 1$之间的约束。此外，我们还计算了DE的微扰，由于DE的演化是由标量场的动力学激发的，因此可以使用齐次的和它的微扰来确定潜在的形式和暗能量的性质。由于我们的参数化是在$L$上，我们可以很容易地将它与标量势$V(ϕ)$联系起来。

英文摘要：

We propose a new Dark Energy parametrization based on the dynamics of a scalar field. We use an equation of state $w=(x-1)/(x+1)$, with $x=E_k/V$, the ratio of kinetic energy $E_k=\dotϕ^2/2$ and potential $V$. The eq. of motion gives $x=(L/6)(V/3H^2)$ and with a solution $x=([1+2 L/3(1+y)]^{1/2}-1)(1+y)/2$ where $y\equiv \rm/V$ and $L\equiv (V'/V)^2 (1+q)^2,\, q\equiv\ddot\p/V'$. Since the universe is accelerating at present time we use the slow roll approximation in which case we have $|q|\ll 1$ and $L\simeq (V'/V)^2$. However, the derivation of $L$ is exact and has no approximation. By choosing an appropriate ansatz for $L$ we obtain a wide class of behavior for the evolution of Dark Energy without the need to specify the potential $V$. In fact $w$ can either grow and later decrease, or other way around, as a function of redshift and it is constraint between $-1\leq w\leq 1$ as for any canonical scalar field with only gravitational interaction. Furthermore, we also calculate the perturbations of DE and since the evolution of DE is motivated by the dynamics of a scalar field the homogenous and its perturbations can be used to determine the form of the potential and the nature of Dark Energy. Since our parametrization is on $L$ we can easily connect it with the scalar potential $V(ϕ)$.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

摘要：

英文摘要：

相关论文