Quantum cloning and the capacity of the Pauli channel

  title={Quantum cloning and the capacity of the Pauli channel},
  author={Nicolas J. Cerf},
  • N. Cerf
  • Published 22 March 1998
  • Physics
A family of quantum cloning machines is introduced that produce two approximate copies from a single quantum bit, while the overall input-to-output operation for each copy is a Pauli channel. A no-cloning inequality is derived, describing the balance between the quality of the two copies. This also provides an upper bound on the quantum capacity of the Pauli channel with probabilities $p_x$, $p_y$ and $p_z$. The capacity is shown to be vanishing if $(\sqrt{p_x},\sqrt{p_y},\sqrt{p_z})$ lies… 
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