Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review A

Generalized universal cloning and purification in quantum information by multistep state symmetrization

L. Masullo, Marco Ricci, F. De Martini

Published Dec 9, 2005• 8 citations
Publisher

Abstract

A general multistep linear state symmetrization device for photonic qubits is presented together with the experimental realizations of the $1\ensuremath{\rightarrow}3$ and $2\ensuremath{\rightarrow}3$ universal optimal quantum cloning machines and of a 3-qubit purification procedure. Since the present method exploits the bosonic nature of the photons, it can be applied to any particle obeying to the Bose statistics. On a technological perspective, the present protocol is expected to find relevant applications as a multiqubit symmetrization device to be used in modern quantum-information networks.

DOI
10.1103/physreva.72.060304

Related papers

Realization of a General Multi-step Quantum Cloning Machine

L. Masullo, Ricci, M., F. De Martini

A general multi-step N->M probabilistic optimal universal cloning protocol is presented together with the experimental realization of the (1 -> 3) and (2 -> 3) machines. Since the present method exploits the bosonic nature of the photons, it can be applied to any particle obeying to the Bose statistics. On a technological perspective, the present protocol is expected to find applications as a novel, multi-qubit symmetrizator device to be used in modern quantum information networks.

arXiv:quant-ph/0412040•Dec 6, 2004•0 citations

Optical realization of universal quantum cloning

Yun‐Feng Huang, Wanli Li, Chuan‐Feng Li +3 more

Beyond the no-cloning theorem, the universal symmetric quantum cloning machine was first addressed by Bu\ifmmode \check{z}\else \v{z}\fi{}ek and Hillery. Here, we realized the $\stackrel{\ensuremath{\rightarrow}}{1}$2 qubit Bu\ifmmode \check{z}\else \v{z}\fi{}ek-Hillery cloning machine with linear optical devices. This method relies on the representation of several qubits by a single photon. We showed that the fidelities between the two output qubits and the original qubit are both $\frac{5}{6}$ (which proved to be the optimal fidelity of $\stackrel{\ensuremath{\rightarrow}}{1}$2 qubit universal cloner) for arbitrary input pure states.

arXiv:quant-ph/0006032•Physical Review A•Jun 13, 2001•49 citations

Experimental linear-optical implementation of a multifunctional optimal qubit cloner

Karel Lemr, Karol Bartkiewicz, Antonín Černoch +2 more

We present the first experimental implementation of a multifunctional device for the optimal cloning of one to two qubits. Previous implementations have always been designed to optimize the cloning procedure with respect to one single type of a priori information about the cloned state. In contrast, our ``all-in-one'' implementation is optimal for several prominent regimes such as universal cloning, phase-covariant cloning, and also the first ever realized mirror phase-covariant cloning, when the square of the expected value of Pauli's $Z$ operator is known in advance. In all these regimes the experimental device yields clones with almost maximum achievable average fidelity (97.5$%$ of theoretical limit). Our device has a wide range of possible applications in quantum information processing, especially in quantum communication. For instance, one can use it for incoherent and coherent attacks against a variety of cryptographic protocols, including the Bennett-Brassard 1984 protocol of quantum key distribution through the Pauli damping channels. It can be also applied as a state-dependent photon multiplier in practical quantum networks.

arXiv:1201.6234•Physical Review A•May 25, 2012•31 citations

EXPERIMENTAL REALIZATIONS OF THE 1 → M UNIVERSAL CLONING MACHINE

L. Masullo, Marco Ricci, Fabio Sciarrino +2 more

We report the first experimental realizations of the 1 → M universal cloning machine. Two approaches are carefully described: the adoption of a state symmetrization linear optical procedure and of the quantum injected optical parametric amplifier. Furthermore, this device is adopted to generate optimally distinguishable multi-photon quantum superposition states.

International Journal of Quantum Information•Jun 1, 2006•0 citations

Realization of universal optimal quantum machines by projective operators and stochastic maps

Fabio Sciarrino, Carlo Sias, Marco Ricci +1 more

Optimal quantum machines can be implemented by linear projective operations. In the present work a general qubit symmetrization theory is presented by investigating the close links to the qubit purification process and to the programmable teleportation of any generic optimal antiunitary map. In addition, the contextual realization of the $N\ensuremath{\rightarrow}M$ cloning map and of the teleportation of the $N\ensuremath{\rightarrow}(M\ensuremath{-}N)$ universal-NOT (UNOT) gate is analyzed by a very general angular momentum theory. An extended set of experimental realizations by state symmetrization linear optical procedures is reported. These include the $1\ensuremath{\rightarrow}2$ cloning process, the UNOT gate and the quantum tomographic characterization of the optimal partial transpose map of polarization encoded qubits.

arXiv:quant-ph/0407176•Physical Review A•Nov 1, 2004•35 citations

Experimental demonstration of optimal universal asymmetric quantum cloning of polarization states of single photons by partial symmetrization

Antonín Černoch, Jan Soubusta, Lucie Čelechovská +2 more

We report on experimental implementation of the optimal universal asymmetric $1\ensuremath{\rightarrow}2$ quantum cloning machine for qubits encoded into polarization states of single photons. Our linear-optical machine performs asymmetric cloning by partially symmetrizing the input polarization state of signal photon and a blank copy idler photon prepared in a maximally mixed state. We show that the employed method of measurement of mean clone fidelities exhibits strong resilience to imperfect calibration of the relative efficiencies of single-photon detectors used in the experiment. Reliable characterization of the quantum cloner is thus possible even when precise detector calibration is difficult to achieve.

arXiv:0911.1227•Physical Review A•Dec 2, 2009•6 citations
A general multistep linear state symmetrization device for photonic qubits is presented together with the experimental realizations of the 1\ensuremath→31\ensuremath{\rightarrow}31\ensuremath→3 and 2\ensuremath→32\ensuremath{\rightarrow}32\ensuremath→3 universal optimal quantum cloning machines and of a 3-qubit purification procedure. Since the present method exploits the bosonic nature of the photons, it can be applied to any particle obeying to the Bose statistics. On a technological perspective, the present protocol is expected to find relevant applications as a multiqubit symmetrization device to be used in modern quantum-information networks.
Beyond the no-cloning theorem, the universal symmetric quantum cloning machine was first addressed by Bu\ifmmode \check{z}\else \v{z}\fi{}ek and Hillery. Here, we realized the $\stackrel{\ensuremath{\rightarrow}}{1}$2 qubit Bu\ifmmode \check{z}\else \v{z}\fi{}ek-Hillery cloning machine with linear optical devices. This method relies on the representation of several qubits by a single photon. We showed that the fidelities between the two output qubits and the original qubit are both 56\frac{5}{6}65​ (which proved to be the optimal fidelity of $\stackrel{\ensuremath{\rightarrow}}{1}$2 qubit universal cloner) for arbitrary input pure states.
We present the first experimental implementation of a multifunctional device for the optimal cloning of one to two qubits. Previous implementations have always been designed to optimize the cloning procedure with respect to one single type of a priori information about the cloned state. In contrast, our ``all-in-one'' implementation is optimal for several prominent regimes such as universal cloning, phase-covariant cloning, and also the first ever realized mirror phase-covariant cloning, when the square of the expected value of Pauli's ZZZ operator is known in advance. In all these regimes the experimental device yields clones with almost maximum achievable average fidelity (97.5% of theoretical limit). Our device has a wide range of possible applications in quantum information processing, especially in quantum communication. For instance, one can use it for incoherent and coherent attacks against a variety of cryptographic protocols, including the Bennett-Brassard 1984 protocol of quantum key distribution through the Pauli damping channels. It can be also applied as a state-dependent photon multiplier in practical quantum networks.
Optimal quantum machines can be implemented by linear projective operations. In the present work a general qubit symmetrization theory is presented by investigating the close links to the qubit purification process and to the programmable teleportation of any generic optimal antiunitary map. In addition, the contextual realization of the $N\ensuremath{\rightarrow}M$ cloning map and of the teleportation of the $N\ensuremath{\rightarrow}(M\ensuremath{-}N)$ universal-NOT (UNOT) gate is analyzed by a very general angular momentum theory. An extended set of experimental realizations by state symmetrization linear optical procedures is reported. These include the $1\ensuremath{\rightarrow}2$ cloning process, the UNOT gate and the quantum tomographic characterization of the optimal partial transpose map of polarization encoded qubits.
We report on experimental implementation of the optimal universal asymmetric $1\ensuremath{\rightarrow}2$ quantum cloning machine for qubits encoded into polarization states of single photons. Our linear-optical machine performs asymmetric cloning by partially symmetrizing the input polarization state of signal photon and a blank copy idler photon prepared in a maximally mixed state. We show that the employed method of measurement of mean clone fidelities exhibits strong resilience to imperfect calibration of the relative efficiencies of single-photon detectors used in the experiment. Reliable characterization of the quantum cloner is thus possible even when precise detector calibration is difficult to achieve.