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arXiv · 1511.04309

Quantum-phase synchronization

Lukas J. Fiderer·Marek Kuś·Daniel Braun
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Abstract

We study mechanisms that allow one to synchronize the quantum phase of two qubits relative to a fixed basis. Starting from one qubit in a fixed reference state and the other in an unknown state, we find that contrary to the impossibility of perfect quantum cloning, the quantum-phase can be synchronized perfectly through a joined unitary operation. When both qubits are initially in a pure unknown state, perfect quantum-phase synchronization through unitary operations becomes impossible. In this situation we determine the maximum average quantum-phase synchronization fidelity, the distribution of relative phases and fidelities, and identify optimal quantum circuits that achieve this maximum fidelity. A subset of these optimal quantum circuits enable perfect quantum-phase synchronization for a class of unknown initial states restricted to the equatorial plane of the Bloch sphere.

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Lukas J. Fiderer, Marek Kuś, Daniel Braun. 2016-11-03. Quantum-phase synchronization. https://doi.org/10.1103/physreva.94.032336

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