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SUMMARY:Crystalline gravity - 't Hooft\, G (Utrecht)
DTSTART:20090327T140000Z
DTEND:20090327T150000Z
UID:TALK17557@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:Matter interacting classically with gravity in 3+1 dimensions 
 usually gives rise to a continuum of degrees of freedom\, so that\, in any
  attempt to quantize the theory\, ultraviolet divergences are nearly inevi
 table. We now decided to investigate matter of a form that only displays a
  finite number of degrees of freedom in compact sections of space-time. In
  finite domains\, one has only exact\, analytic solutions. This is achieve
 d by limiting ourselves to straight pieces of string\, surrounded by local
 ly flat sections of space-time. We investigate the equations of motion for
  such forms of matter. Globally\, the model is not finite\, because soluti
 ons tend to generate infinite fractals. The model is not (yet) quantized\,
  but could serve as an interesting setting for\nanalytical approaches to c
 lassical general relativity\, as well as a possible stepping stone for qua
 ntum models. Details of its properties are explained\, but some problems r
 emain unsolved\, such as a complete description of all possible interactio
 ns.
LOCATION:Seminar Room 1 Newton Institute
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