What are some examples of dynamical systems in General Relativity?

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Discussion Overview

The discussion revolves around identifying examples of dynamical systems within the framework of General Relativity, particularly in relation to advanced differential geometry. Participants explore how to formulate dynamical systems from physical problems, such as the dynamics of particles in Schwarzschild geometry.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks examples of dynamical systems in General Relativity, specifically related to analyzing a massive particle outside a black hole using the Schwarzschild metric.
  • Another participant suggests using a Hamiltonian approach with kinetic and effective potential energy to model the dynamics of a free massive particle in Schwarzschild geometry.
  • A participant notes that the Schwarzschild metric cannot be used for a two-body problem unless modeling a test mass and recommends looking into Chris Hillman's introduction and the double Kerr solution.
  • There is a mention that a full analytical solution for a two-body problem is impossible, necessitating approximations or numerical solutions.
  • One participant expresses interest in analyzing behaviors within local neighborhoods rather than seeking full solutions.
  • Another participant proposes using the field equations to derive a metric, suggesting that the coupled non-linear differential equations can be analyzed for metric behavior in local neighborhoods.
  • A later reply indicates skepticism about the simplicity of deriving metrics from field equations.
  • Critical phenomena in General Relativity is highlighted as a relevant example, with a reference to a review by Gundlach for further exploration.

Areas of Agreement / Disagreement

Participants express various approaches to modeling dynamical systems, with some disagreement on the feasibility of certain methods, such as using the Schwarzschild metric for two-body problems. The discussion remains unresolved regarding the best approach to formulate these systems.

Contextual Notes

Participants acknowledge limitations in their approaches, such as the complexity of two-body problems and the challenges in deriving metrics from field equations. There is also a recognition of the need for approximations or numerical methods in certain scenarios.

Kreizhn
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I'm doing a research project for a class in advanced differential geometry, and have chosen to cover dynamical systems. However, I've found that the relationship between dynamical systems is limited to exploring flows on manifolds in the most abstract sense. As a result, I was hoping on expand on my topic by including general relativity (since it seems to be strongly based on differential geometry).

Can anybody think of any dynamical systems in General Relativity that I can play around with? Even suggestions on how to formulate dynamical systems out of problems that have been solved in a purely physical sense would be helpful.

For example, I'm working on trying to analyze the dynamics of a massive particle outside of a black hole using the Schwarzschild metric. I know how to do this physically, but am not entirely sure as how to form the corresponding dynamical system.

Any ideas?
 
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In fact, in particular I would be content to find a way to transform this situation into a dynamical system

A free massive particle with proper time \tau is evolving in a Schwarzschild geometry produced by a massive object of mass M, located at r = 0

I'm really not sure how I should go about this though. Could I perhaps use a Hamiltonian approach with Kinetic and (Effective) potential energy?
 
Kreizhn said:
For example, I'm working on trying to analyze the dynamics of a massive particle outside of a black hole using the Schwarzschild metric. I know how to do this physically, but am not entirely sure as how to form the corresponding dynamical system.
Unless you are modeling a test mass you cannot use the Schwarzschild metric for a two body problem. To approach a two body problem you might want to take a look at Chris Hillman's short introduction over here: http://www.mountainman.com.au/news98_x.htm
You also might want to lookup the double Kerr solution.

Be aware though that a full analytical solution for a two body problem is impossible. One either makes an approximation or resort to numerical solutions.

For those who are interested here is a link to some visualisations derived from numerical solutions: http://jean-luc.aei.mpg.de/Movies/
 
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I don't necessarily want full solutions. I'd be more than content to analyze behaviours within local neighbourhoods.

Thanks for the link.
 
I'm not too terribly concerned with the complexity of the problem so long as I have something I can play around with
 
I've realized I've been thinking about this the wrong way. Instead of modeling particles, I can just use the field equations to 'derive' a metric. That is, the field equations yield a set of coupled non-linear differential equations which I can use to analyze the behaviour of a metric in local neighbourhoods.
 
If only it were that simple...
 
Critical phenomena is general relativity is an excellent example that can be described in the terms of what you want. The review by Gundlach is a good place to start.

http://arxiv.org/abs/0711.4620
 

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