Optimal cloning of qubits given by an arbitrary axisymmetric distribution on the Bloch sphere

Journal Article · Fri Oct 15 04:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.82.042330· OSTI ID:21450748

Bartkiewicz, Karol; Miranowicz, Adam ^[1]

---

1. Faculty of Physics, Adam Mickiewicz University, 61-614 Poznan (Poland)

We find an optimal quantum cloning machine, which clones qubits of arbitrary symmetrical distribution around the Bloch vector with the highest fidelity. The process is referred to as phase-independent cloning in contrast to the standard phase-covariant cloning for which an input qubit state is a priori better known. We assume that the information about the input state is encoded in an arbitrary axisymmetric distribution (phase function) on the Bloch sphere of the cloned qubits. We find analytical expressions describing the optimal cloning transformation and fidelity of the clones. As an illustration, we analyze cloning of qubit state described by the von Mises-Fisher and Brosseau distributions. Moreover, we show that the optimal phase-independent cloning machine can be implemented by modifying the mirror phase-covariant cloning machine for which quantum circuits are known.

• OSTI ID: 21450748
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 82; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AXIAL SYMMETRY
DISTRIBUTION
FUNCTIONS
INFORMATION
MECHANICS
QUANTUM INFORMATION
QUANTUM MECHANICS
QUANTUM STATES
QUBITS
SYMMETRY
TENSORS
TRANSFORMATIONS
VECTORS