Gravity, Chaos and Time Machines
نویسندگان
چکیده
2+1 gravity for spacetimes with topology R × T has been much studied. We add a description of how to extend these spacetimes across a Cauchy horizon into a region where the torus becomes Lorentzian. The result is a one parameter family of tori given by a geodesic in the ”Teichmüller space” of Lorentzian tori. We describe this in detail. We also point out that if the modular group is regarded as part of the gauge group then these spacetimes offer a nice toy model for the dynamics of Bianchi IX models; in the region where the tori are spacelike the dynamics is described exactly by a hyperbolic billiard. On the other hand the modular group acts ergodically on the Teichmüller space of Lorentzian tori. Email address: [email protected]. Supported by NFR. Email address: [email protected]
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