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JanG
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Your other metric is not a solution to Einstein field equation. The metric coefficients $g_{00}$ and $g_{rr}$ are related to each other through Einstein field equations. In static case one can usethe equation below (1$u\equiv r^2/R^2$) from the reference to. Using it one can check whether the new metric fulfills that equationsatisfies it. I expect $${\rm e}^{-\lambda}\frac{\rm d}{{\rm d} u} \left( {\rm e}^{-\lambda}\frac{\rm d}{{\rm d}u}{\rm e}^{\nu}\right) = \frac{1}{4}\frac{\rm d}{{\rm d}u}\left(\frac{1-{\rm e}^{-2\lambda}}{u}\right)~{\rm e}^{\nu}~.\tag{1}$$

The easiest way to do it will be notis to notice that both metrics satisfy ${\rm e}^{\nu}={\rm e}^{-\lambda}$ what simplifies the caseequation $(1)$ to
\begin{equation}\label{compactform2} \frac{\rm d}{{\rm d} u} \left(\frac{\rm d}{{\rm d}u}{\rm e}^{\nu}\right) = \frac{1}{2}\frac{\rm d}{{\rm d}u}\left(\frac{1-{\rm e}^{-2\lambda}}{u}\right),~\tag{2} \end{equation} The solution of equation $(2)$ reads $${\rm e}^{-2\lambda}=1+\frac{C_{1}}{\sqrt{u}}+C_{2}~u\equiv1+\frac{\tilde{C}_{1}}{r}+\tilde{C}_{2}~r^2.~\tag{3}$$ The vacuum solution (Schwarzschild solution) corresponds to $\tilde{C_{2}}\equiv0$. However

Concluding, please check it for yourself. I could possible made a mistake in my calculationthe only metric satisfying $~g_{00}\cdot g_{rr}=1$ relation is the Schwarzschild metric (with or without cosmological term).

The metric coefficients $g_{00}$ and $g_{rr}$ are related to each other through Einstein field equations. In static case one can use equation (1) from the reference to check whether the new metric fulfills that equation. I expect it will be not the case. However, please check it for yourself. I could possible made a mistake in my calculation.

Your other metric is not a solution to Einstein field equation. The metric coefficients $g_{00}$ and $g_{rr}$ are related to each other through the equation below ($u\equiv r^2/R^2$). Using it one can check whether the new metric satisfies it. $${\rm e}^{-\lambda}\frac{\rm d}{{\rm d} u} \left( {\rm e}^{-\lambda}\frac{\rm d}{{\rm d}u}{\rm e}^{\nu}\right) = \frac{1}{4}\frac{\rm d}{{\rm d}u}\left(\frac{1-{\rm e}^{-2\lambda}}{u}\right)~{\rm e}^{\nu}~.\tag{1}$$

The easiest way to do it is to notice that both metrics satisfy ${\rm e}^{\nu}={\rm e}^{-\lambda}$ what simplifies the equation $(1)$ to
\begin{equation}\label{compactform2} \frac{\rm d}{{\rm d} u} \left(\frac{\rm d}{{\rm d}u}{\rm e}^{\nu}\right) = \frac{1}{2}\frac{\rm d}{{\rm d}u}\left(\frac{1-{\rm e}^{-2\lambda}}{u}\right),~\tag{2} \end{equation} The solution of equation $(2)$ reads $${\rm e}^{-2\lambda}=1+\frac{C_{1}}{\sqrt{u}}+C_{2}~u\equiv1+\frac{\tilde{C}_{1}}{r}+\tilde{C}_{2}~r^2.~\tag{3}$$ The vacuum solution (Schwarzschild solution) corresponds to $\tilde{C_{2}}\equiv0$.

Concluding, the only metric satisfying $~g_{00}\cdot g_{rr}=1$ relation is the Schwarzschild metric (with or without cosmological term).

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JanG
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The metric coefficients $g_{00}$ and $g_{rr}$ are related to each other through Einstein field equations. In static case one can use equation (1) from the reference to check whether the new metric fulfills that equation. I expect it will be not the case because using your new metric the calculated pressure and energy density are both zero, and the only static spherically symmetric vacuum solution is the Schwarzschild one. However, please check it for yourself. I could possible made a mistake in themy calculation.

The metric coefficients $g_{00}$ and $g_{rr}$ are related to each other through Einstein field equations. In static case one can use equation (1) from the reference to check whether the new metric fulfills that equation. I expect it will be not the case because using your new metric the calculated pressure and energy density are both zero, and the only static spherically symmetric vacuum solution is the Schwarzschild one. However, please check it for yourself. I could possible made a mistake in the calculation.

The metric coefficients $g_{00}$ and $g_{rr}$ are related to each other through Einstein field equations. In static case one can use equation (1) from the reference to check whether the new metric fulfills that equation. I expect it will be not the case. However, please check it for yourself. I could possible made a mistake in my calculation.

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JanG
  • 2k
  • 6
  • 16

The metric coefficients $g_{00}$ and $g_{rr}$ are related to each other through Einstein field equations. In static case one can use equation (1) from the reference to check whether the new metric fulfills that equation. I expect it will be not the case because using your new metric the calculated pressure and energy density are both zero, and the only static spherically symmetric vacuum solution is the Schwarzschild one. However, please check it for yourself. I could possible made a mistake in the calculation.