Abstract
After the appearance of the no-cloning theorem, approximate quantum cloning machines (QCMs) has become a well-studied subject in quantum information theory. Among several measures to quantify the performance of a QCM, single-qudit fidelity and global fidelity have been most widely used. In this paper we compute the optimal global fidelity for phase-covariant cloning machines via semidefinite programming optimization, thereby completing a remaining gap in the previous results on QCMs. We also consider optimal simulations of the cloning and transpose cloning map, both by a direct optimization and by a composition of component-wise optimal QCMs. For the cloning map the composition method is suboptimal whereas for the transpose cloning map the method is asymptotically optimal.
Original language | English (US) |
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Article number | 022405 |
Journal | Physical Review A |
Volume | 106 |
Issue number | 2 |
DOIs | |
State | Published - Aug 2022 |
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics