J4 ›› 2015, Vol. 32 ›› Issue (4): 438-444.

• Quantum Optics • Previous Articles     Next Articles

Optimal phase-covariant quantum cloning

Zhang Gang, Pan Guozhu, Yuan Hao   

  1. 1 School of Mechanical and Electronic Engineering, West Anhui University, Lu’ an 237012, China;
     2 School of Material and Chemical Engineering, West Anhui University, Lu’ an 237012, China
  • Received:2015-04-01 Revised:2015-04-07 Published:2015-07-28 Online:2015-08-04

Abstract:

In quantum information science, quantum cloning theory is a basic one that provides an absolute security of quantum cryptography. We derive the explicit transformations of the optimal 1→M=d+1 phase-covariant quantum cloning in d dimensions, and then generalize this kind of cloning machine to the 1→M=kd+1 (k integer) case and obtain the explicit transformation. By exploiting the formulation of the nonoptimal 2→M=2k+1 phase-covariant quantum cloning in 2 dimensions, we derive the optimal cloning transformation. The copy fidelities of the two kinds of cloning machines are coincident with the theoretical values found.

Key words: Quantum information, Quantum cryptography, Quantum cloning, Universal quantum cloning, Phase-covariant quantum cloning

CLC Number: