Global casual structure of space-time, well-behaved function

In summary, the conversation mentions a black hole solution with a metric function f(r) and scalar function ##\varphi(r)##. The solution is described by the equations ##f(r)=\frac{1}{4}+\left(\frac{Z^{2}}{2r^{2}}\right)^{2}-\frac{1}{3}\Lambda r^{2}## and ##\varphi(r)=\pm\left(\frac{1}{\sqrt{2}l}\right)r##, where ##Z##, ##\Lambda## and ##l## are constants. It is unclear from this information whether this solution actually describes a black hole. The global causal structure of this space-time solution and the
  • #1
dhalilsim
3
0
I obtained the black hole solution whose the metric function f(r) and scalar function ##\varphi(r)## are ;

##f(r)=\frac{1}{4}+\left(\frac{Z^{2}}{2r^{2}}\right)^{2}-\frac{1}{3}\Lambda r^{2}##
##\varphi(r)=\pm\left(\frac{1}{\sqrt{2}l}\right)r##
where ##Z##, ##\Lambda## and ##l## are just constants.

What is the global causal structure of this space-time solution described by Eqs. above?
Is the dilaton field well-behaved for r —-> infinity?

[Moderator's Note: deleted the second part of the post, needs to be posted in a separate thread.]
 
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  • #2
These look like two unrelated questions, which you should ask in two separate threads. Also, there is far too little information for anyone to be able to understand what you're actually asking about.
 
  • #3
dhalilsim said:
I obtained the black hole solution

Why do you think this solution describes a black hole?
 
  • #4
bcrowell said:
These look like two unrelated questions, which you should ask in two separate threads.

Agreed, so I deleted the second one from the OP of this thread. dhalilsim, please start a separate thread if you want an answer to the other question (and it would help if you actually gave the specific equations you are asking about).
 
  • #5
dhalilsim said:
whose the metric function f(r) and scalar function ##\varphi(r)##

What are these supposed to mean? As bcrowell says, there is far too little information here to understand what you are talking about. Please give a reference or quite a bit more context (preferably both).
 
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  • #6
Telling us f(r) and ##\varphi(r)## does not directly gives us the line element / metric. I'm not sure what I'll be able to say about the global causal structure given the metric, but the first step is to get the metric.
 

1. What is the global casual structure of space-time?

The global casual structure of space-time refers to the overall arrangement of events and how they are causally connected. This includes the concept of causality, which states that any event can only be affected by events that are within its past light cone, or in simpler terms, events that are close enough for a signal to reach them. This structure is an important aspect of understanding the behavior of objects and phenomena in the universe.

2. What is a well-behaved function?

A well-behaved function is a mathematical function that behaves in a predictable and smooth manner. This means that it has a continuous graph and follows certain rules, such as being differentiable at all points within its domain. In the context of the global casual structure of space-time, well-behaved functions are often used to describe the behavior of objects and phenomena within the framework of general relativity.

3. How do well-behaved functions relate to the global casual structure of space-time?

Well-behaved functions are used in the study of the global casual structure of space-time because they can help us understand how objects and phenomena behave within this framework. By using mathematical models and equations, scientists can make predictions and gain a deeper understanding of the causality and structure of the universe.

4. What are some examples of well-behaved functions?

Examples of well-behaved functions include polynomials, trigonometric functions, and exponential functions. These functions have smooth and continuous graphs and follow certain rules, making them useful in describing the behavior of objects and phenomena in space-time. Other examples include Gaussian functions, logarithmic functions, and rational functions.

5. Why is understanding the global casual structure of space-time important?

Understanding the global casual structure of space-time is important because it helps us make sense of the universe and its behavior. By studying the interactions between objects and phenomena, we can gain insights into the fundamental laws of physics and how the universe has evolved over time. This understanding also has practical applications, such as in the development of technologies like GPS and in predicting and mitigating potential hazards, such as black holes or gravitational waves.

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