Background independence in a nutshell: the dynamics of a tetrahedron

@article{Rovelli2005BackgroundII,
  title={Background independence in a nutshell: the dynamics of a tetrahedron},
  author={Carlo Rovelli and Daniele Colosi and Luisa Doplicher and Winston J. Fairbairn and Leonardo Modesto and Karim Noui},
  journal={Classical and Quantum Gravity},
  year={2005},
  volume={22},
  pages={2971-2989}
}
We study how physical information can be extracted from a background-independent quantum system. We use an extremely simple 'minimalist' system that models a finite region of 3D Euclidean quantum spacetime with a single equilateral tetrahedron. We show that the physical information can be expressed as a boundary amplitude. We illustrate how the notions of 'evolution' in a boundary proper time and 'vacuum' can be extracted from the background-independent dynamics. 

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