arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1306.5090gr-qc
收藏

具有非最小动力学耦合和幂律势的宇宙学

Cosmology with nonminimal kinetic coupling and a power-law potential

Maria A. Skugoreva, Sergey V. Sushkov, Alexei V. Toporensky

摘要:

我们考虑了引力理论中的宇宙动力学,标量场与引力有非最小的动力学耦合$κG_{μν}ϕ^μϕ^ν$和幂律势$V(ϕ)=V_0ϕ^N$。利用动力系统方法,我们分析了所研究的模型的所有可能的渐近状态,并证明了对于具有$0<N<2$的倾斜势,存在一个对应于早期暴胀宇宙的准de Sitter渐近$H={1}/{\sqrt{9κ}}$.与标准暴胀情形相比,动力学耦合暴胀不依赖于标量场势,而仅由耦合参数$κ$决定。我们得到存在两个不同的后期渐近制度。第一个导致了通常的权力状宇宙学演化与$H=1/3t$,而第二个代表了晚期暴胀宇宙与$H=1/\sqrt{3κ}$。这个二次暴胀阶段只依赖于$κ$,并且是具有非最小动力学耦合的模型的一个特殊特征。另外,渐近分析表明,对于N=2的二次势,渐近态定性地保持不变,而对于N>2的陡势,动力学耦合暴胀是不可能的.使用数值分析,我们还构建了精确的宇宙学解,并找到初始条件导致初始动力学耦合通货膨胀其次是一个“优雅”的振荡出口或二次通货膨胀。

英文摘要:

We consider cosmological dynamics in the theory of gravity with the scalar field possessing a nonminimal kinetic coupling to gravity, $κG_{μν}ϕ^μϕ^ν$, and the power-law potential $V(ϕ)=V_0ϕ^N$. Using the dynamical system method, we analyze all possible asymptotical regimes of the model under investigation and show that for sloping potentials with $0<N<2$ there exists a quasi-de Sitter asymptotic $H={1}/{\sqrt{9κ}}$ corresponding to an early inflationary Universe. In contrast to the standard inflationary scenario, the kinetic coupling inflation does not depend on a scalar field potential and is only determined by the coupling parameter $κ$. We obtain that there exist two different late-time asymptotical regimes. The first one leads to the usual power-like cosmological evolution with $H=1/3t$, while the second one represents the late-time inflationary Universe with $H=1/\sqrt{3κ}$. This secondary inflationary phase depends only on $κ$ and is a specific feature of the model with nonminimal kinetic coupling. Additionally, an asymptotical analysis shows that for the quadric potential with N=2 the asymptotical regimes remain qualitatively the same, while the kinetic coupling inflation is impossible for steep potentials with N>2. Using a numerical analysis, we also construct exact cosmological solutions and find initial conditions leading to the initial kinetic coupling inflation followed either by a "graceful" oscillatory exit or by the secondary inflation.

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。

↑