Please help solve the equation in black hole f(R) theories

In summary, the conversation discusses trying to solve an equation from a paper, but the approach taken does not match the results in the paper. The equation being solved involves multiple variables and derivatives, and the output shows a potential mistake in the calculations.
  • #1
Boy_saber
1
0
In the paper https://arxiv.org/abs/1210.4699. How to solve this equation?

1.jpg


I've tried it, it's not same as in this paper. Even zero order still not the same.
This is what I try to do at zero order.

input

$$E=E_0\left(r_0\right)$$
$$H=H_0\left(r_0\right)$$
$$b=b\left(r_0\right)$$
$$R=R_0\left(r_0\right)$$
$$\Phi =\Phi _0\left(r_0\right)$$
$$r=r_0$$
$$g^{11}=1-\frac{b}{r}$$
$$\Box f_R=H g^{11} \left(\frac{\partial R}{\partial r_0}\right){}^2+E \left(\left(1-\frac{b}{r}\right) \left(\frac{\partial R}{\partial r_0} \left(-\frac{\partial \Phi }{\partial r_0}\right)+\frac{\frac{\partial R}{\partial r_0}}{r}+\frac{\partial }{\partial r_0}\frac{\partial R}{\partial r_0}\right)+\frac{\left(1-\frac{\partial b}{\partial r_0}\right) \frac{\partial R}{\partial r_0}}{r}\right)$$

output

$$-\frac{b\left(r_0\right) H_0\left(r_0\right) R_0'\left(r_0\right){}^2}{r_0}+\frac{b\left(r_0\right) E_0\left(r_0\right) R_0'\left(r_0\right) \Phi _0'\left(r_0\right)}{r_0}-\frac{E_0\left(r_0\right) b_0'\left(r_0\right) R_0'\left(r_0\right)}{r_0}-\frac{b\left(r_0\right) E_0\left(r_0\right) R_0'\left(r_0\right)}{r_0^2}-\frac{b\left(r_0\right) E_0\left(r_0\right) R_0''\left(r_0\right)}{r_0}+H_0\left(r_0\right) R_0'\left(r_0\right){}^2-E_0\left(r_0\right) R_0'\left(r_0\right) \Phi _0'\left(r_0\right)+\frac{2 E_0\left(r_0\right) R_0'\left(r_0\right)}{r_0}+E_0\left(r_0\right) R_0''\left(r_0\right)$$

Where did I make a mistake?
 
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  • #2


It is difficult to pinpoint the exact mistake without more context and information about the specific equation and problem being solved. However, it is possible that there may be a missing term or a sign error in the output equation. It is also important to carefully check all the inputs and their derivatives to ensure they are correct. It may also be helpful to consult with a colleague or a subject expert for further assistance in solving the equation.
 

1. What is the equation in black hole f(R) theories?

The equation in black hole f(R) theories is a modified version of Einstein's field equations that describes the behavior of gravity in the presence of a black hole. It includes an additional term, f(R), which represents a modification to the theory of gravity.

2. How is the equation solved?

The equation in black hole f(R) theories can be solved using numerical methods or by making simplifying assumptions about the form of the f(R) term. In some cases, exact solutions can be found, but in most cases, numerical methods are necessary.

3. What is the significance of solving this equation?

Solving the equation in black hole f(R) theories can help us better understand the behavior of gravity in extreme environments, such as near a black hole. It can also provide insights into the nature of dark matter and dark energy, which are thought to play a role in the behavior of gravity at large scales.

4. Are there any applications of this equation?

Yes, there are potential applications of the equation in black hole f(R) theories in fields such as astrophysics and cosmology. It could also have implications for the development of new technologies, such as advanced propulsion systems.

5. What are the current challenges in solving this equation?

One of the main challenges in solving the equation in black hole f(R) theories is the complexity of the equation and the need for advanced mathematical and computational techniques. Another challenge is the lack of observational data to test the predictions of this theory, which makes it difficult to validate the solutions.

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