变物理常数与锂问题
Varying physical constants and the lithium problem
摘要：
我们使用最近发表的变物理常数（VPC）方法来解决原始锂丰度问题。我们用这种方法计算的$7Li$与氢$7Li/H=1.400(\pm 0.023){\times}10^{-10}$的比值比用标准λ冷暗物质（$Λ$ CDM）宇宙学模型估计的值低约4倍，并且与$1.6(\pm 0.3){\times}10^{-10}$最一致的观测值一致。在VPC方法中，爱因斯坦方程被修改为包括光速$c$，引力常数$G$和宇宙学常数$Λ$的变化，使用Einstein-Hilbert作用。这种方法应用于宇宙学自然会导致普朗克常数$\hbar$和玻尔兹曼常数PDMATHAMT的变化。它们在比例因子$a\ll 1$处接近固定值：$c=c_0/e$、$G=G_0/e^3$、$\hbar=\hbar_0/e$和$k_B=k_{B0}/e^{5/4}$，其中$e$是欧拉数（=2.7183）。由于VPC宇宙学在非常小的尺度因子下简化为与$Λ$ CDM宇宙学相同的形式，因此我们可以使用现有的大爆炸核合成（BBN）代码AlterBBN进行上述更改来计算VPC宇宙学下的轻元素丰度。在重子光子比$η=6.1{\times}10^{-10}$下计算的其他丰度中，有：$4He/H =0.2478 (\pm 0.041)$、$D/H =2.453(\pm 0.041){\times}10^{-5}$和$3 He/H=2.940(\pm 0.049){\times}10^{-5}$。
英文摘要：
We have used the recently published varying physical constants (VPC) approach to resolve the primordial lithium abundance problem. The value of the ratio of $7Li$ to hydrogen $7Li/H=1.400(\pm 0.023){\times}10^{-10}$ we have calculated using this approach is about four times lower than that estimated using the standard lambda cold dark matter ($Λ$CDM) cosmological model, and is consistent with the most agreed observational value of $1.6(\pm 0.3){\times}10^{-10}$. In the VPC approach Einstein equations are modified to include the variation of the speed of light $c$, gravitational constant $G$ and cosmological constant $Λ$ using the Einstein-Hilbert action. Application of this approach to cosmology naturally leads to the variation of the Plank constant $\hbar$ and the Boltzmann constant $k_B$ as well. They approach fixed values at the scale factor $a\ll 1$: $c=c_0/e$, $G=G_0/e^3$, $\hbar=\hbar_0/e$ and $k_B=k_{B0}/e^{5/4}$, where $e$ is the Euler's number (=2.7183). Since the VPC cosmology reduces to the same form as the $Λ$CDM cosmology at very small scale factors, we could use an existing Big-Bang nucleosynthesis (BBN) code AlterBBN with the above changes to calculate the light element abundances under the VPC cosmology. Among other abundances we have calculated at baryon to photon ratio $η=6.1{\times}10^{-10}$ are: $4He/H =0.2478 (\pm 0.041)$, $D/H =2.453(\pm 0.041){\times}10^{-5}$ and $3 He/H=2.940(\pm 0.049){\times}10^{-5}$.
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