Process-optimized phase-covariant quantum cloning

Chloe Kim, Eric Chitambar

Research output: Contribution to journalArticlepeer-review


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 languageEnglish (US)
Article number022405
JournalPhysical Review A
Issue number2
StatePublished - Aug 2022

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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