Optimal phase-covariant cloning for qubits and qutrits
Abstract
We consider cloning transformations of equatorial qubits |ψφ>=1/(2)(|0>+eiφ|1>) and qutrits |ψφ,θ>=1/(3)(|0>+eiφ|1>+eiθ|2>), with the transformation covariant for rotation of the phases φ and θ. The optimal cloning maps are derived without simplifying assumptions from first principles, for any number of input and output qubits, and for a single-input qutrit and any number of output qutrits. We also compare the cloning maps for global and single-particle fidelities, and we show that the two criteria lead to different optimal maps.
- Publication:
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Physical Review A
- Pub Date:
- April 2003
- DOI:
- arXiv:
- arXiv:quant-ph/0301175
- Bibcode:
- 2003PhRvA..67d2306D
- Keywords:
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- 03.67.-a;
- 03.65.-w;
- Quantum information;
- Quantum mechanics;
- Quantum Physics
- E-Print:
- 8 pages