A de Finetti representation for finite symmetric quantum states

@article{Koenig2004ADF,
  title={A de Finetti representation for finite symmetric quantum states},
  author={Robert Koenig and Renato Renner},
  journal={Journal of Mathematical Physics},
  year={2004},
  volume={46},
  pages={122108}
}
Consider a symmetric quantum state on an n-fold product space, that is, the state is invariant under permutations of the n subsystems. We show that, conditioned on the outcomes of an informationally complete measurement applied to a number of subsystems, the state in the remaining subsystems is close to having product form. This immediately generalizes the so-called de Finetti representation to the case of finite symmetric quantum states. 

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