Telecloning and its reverse process, referred to as remote quantum-information concentration (RQIC), have been attracting considerable interest because of their potential applications in quantum-information processing...Telecloning and its reverse process, referred to as remote quantum-information concentration (RQIC), have been attracting considerable interest because of their potential applications in quantum-information processing. The previous RQIC protocols were focused on the reverse process of the optimal universal telecloning. We here study the reverse process of ancilla-free phase-covariant telecloning (AFPCT). It is shown that the quantum information originally distributed into two spatially separated qubits from a single qubit via the optimal AFPCT procedure can be remotely concentrated back to a single qubit with a certain probability by using an asymmetric W state as the quantum channel.展开更多
The explicit transformations of the 1→ 3 optimal universal quantum cloning and the optimal phase-covariant quantum cloning in d-dimensions are presented, and the dimensionalities of their ancillary systems are both d...The explicit transformations of the 1→ 3 optimal universal quantum cloning and the optimal phase-covariant quantum cloning in d-dimensions are presented, and the dimensionalities of their ancillary systems are both d-dimensions. As d→∞ , their clone fidelities move toward 1/3, showing a classical limit for the fidelity of quantum cloning. Based on the reduction of the unitary transformation of quantum cloning, the transformation of the 1→M=d+1 optimal economical phase-covariant quantum cloning in d-dimensions is derived, and the clone fidelity is covered by the theoretical value.展开更多
This paper proposes a scheme for the implementation of 1→ 3 optimal phase-covariant quantum cloning with trapped ions. In the present protocol, the required time for the whole procedure is short due to the resonant i...This paper proposes a scheme for the implementation of 1→ 3 optimal phase-covariant quantum cloning with trapped ions. In the present protocol, the required time for the whole procedure is short due to the resonant interaction, which is important in view of decoherence. Furthermore, the scheme is feasible based on current technologies.展开更多
We propose a unified scheme to implement the optimal 1→ 3economical phase-covariant quantum cloning and optimal 1→3 economical real state cloning with superconducting quantum interference devices (SQUIDs) in a cavit...We propose a unified scheme to implement the optimal 1→ 3economical phase-covariant quantum cloning and optimal 1→3 economical real state cloning with superconducting quantum interference devices (SQUIDs) in a cavity.During this process,no transfer of quantum information between the SQUIDs and cavity is required.The cavity field is only virtually excited.The scheme is insensitive to cavity decay.Therefore,the scheme can be experimentally realized in the range of current cavity QED techniques.展开更多
This paper presents a very simple method to derive the explicit transformations of the optimal economical 1 to M phase-covariant cloning. The fidelity of clones reaches the theoretic bound [D＇Ar]ano G M and Macchiave...This paper presents a very simple method to derive the explicit transformations of the optimal economical 1 to M phase-covariant cloning. The fidelity of clones reaches the theoretic bound [D＇Ar]ano G M and Macchiavello C 2003 Phys. Rev. A 67 042306]. The derived transformations cover the previous contributions [Delgado Y, Lamata Let al, 2007 Phys. Rev. Lett. 98 150502] in which M must be odd.展开更多
By means of cavity-assisted photon interference, a simple scheme is proposed to implement a symmetric economical phase-covariant quantum cloning machine of two remote qubits, with each in a separate cavity. With our p...By means of cavity-assisted photon interference, a simple scheme is proposed to implement a symmetric economical phase-covariant quantum cloning machine of two remote qubits, with each in a separate cavity. With our present scheme, a high-fidelity cloning machine is realized. Our scheme may be quite useful in terms of distributed quantum information processing.展开更多
In this paper, we derive the explicit transformations of the optimal 1→3, 4, 5 phase-covariant cloning in three dimensions, and then generalize them to the cases of 1 → M = 3n, 3n ＋ 1, 3n ＋ 2 （n ≥ 1 integer） cl...In this paper, we derive the explicit transformations of the optimal 1→3, 4, 5 phase-covariant cloning in three dimensions, and then generalize them to the cases of 1 → M = 3n, 3n ＋ 1, 3n ＋ 2 （n ≥ 1 integer） cloning. The clone fidelities are coincident with the theoretical bounds found.展开更多
We propose an experimentally feasible scheme to implement the economical 1 → M phase-covariant telecloning based on cavity QED. By the resonant interaction of the atoms with cavity field of a high-Q cavity and the di...We propose an experimentally feasible scheme to implement the economical 1 → M phase-covariant telecloning based on cavity QED. By the resonant interaction of the atoms with cavity field of a high-Q cavity and the different coupling strength between atoms and cavity field, the scheme can generate quantum entanglement channel in one step. What is more, the operation time and steps do not increase with the increase of atoms.展开更多
We propose an experimentally feasible scheme to implement the optimal asymmetric economical 1→2 phase-covariant quantum cloning in two dimensions based on the cavity QED technique. The protocol is very simple and onl...We propose an experimentally feasible scheme to implement the optimal asymmetric economical 1→2 phase-covariant quantum cloning in two dimensions based on the cavity QED technique. The protocol is very simple and only two atoms are required. Our scheme is insensitive to the cavity field states and cavity decay. During the processes, the cavity is only virtually excited and it thus greatly prolongs the efficient decoherent time. Therefore, it may be realized in experiment.展开更多
We propose a simple scheme for the implementation of the ancillary-free 1→3 optimal phase-covariant quantum cloning for x-y equatorial qubits in ion-trap system. In the scheme, the vibrational mode is only virtually ...We propose a simple scheme for the implementation of the ancillary-free 1→3 optimal phase-covariant quantum cloning for x-y equatorial qubits in ion-trap system. In the scheme, the vibrational mode is only virtually excited, which is very important in view of decoherence. The present proposal can be realized based on current available technologies.展开更多
In this paper,we present the explicit transformations of the optimal 1 → 3,4,5 phase-covariant cloning in 3 dimensions.The cloning fidelities are covered by the theoretical bounds of the optimal 1 → 3k,3k + 1,3k + 2...In this paper,we present the explicit transformations of the optimal 1 → 3,4,5 phase-covariant cloning in 3 dimensions.The cloning fidelities are covered by the theoretical bounds of the optimal 1 → 3k,3k + 1,3k + 2 phase-covariant cloning of qutrits,where k ≥ 1 is the integral [Phys.Rev.A 67(2003) 042306].展开更多
文摘Telecloning and its reverse process, referred to as remote quantum-information concentration (RQIC), have been attracting considerable interest because of their potential applications in quantum-information processing. The previous RQIC protocols were focused on the reverse process of the optimal universal telecloning. We here study the reverse process of ancilla-free phase-covariant telecloning (AFPCT). It is shown that the quantum information originally distributed into two spatially separated qubits from a single qubit via the optimal AFPCT procedure can be remotely concentrated back to a single qubit with a certain probability by using an asymmetric W state as the quantum channel.
基金supported by the National Natural Science Foundation of China (Grant No.10704001)the Natural Science Foundation of the Education Department of Anhui Province of China (Grant Nos.KJ2010ZD08 and KJ2010B204)the Doctor Research Start-Up Program of Huainan Normal University
文摘The explicit transformations of the 1→ 3 optimal universal quantum cloning and the optimal phase-covariant quantum cloning in d-dimensions are presented, and the dimensionalities of their ancillary systems are both d-dimensions. As d→∞ , their clone fidelities move toward 1/3, showing a classical limit for the fidelity of quantum cloning. Based on the reduction of the unitary transformation of quantum cloning, the transformation of the 1→M=d+1 optimal economical phase-covariant quantum cloning in d-dimensions is derived, and the clone fidelity is covered by the theoretical value.
基金Project supported by the National Natural Science Foundation of China(Grant Nos10574022 and 10575022)the Funds of the Natural Science of Fujian Province,China(Grant Nos Z0512006 and A0210014)
文摘This paper proposes a scheme for the implementation of 1→ 3 optimal phase-covariant quantum cloning with trapped ions. In the present protocol, the required time for the whole procedure is short due to the resonant interaction, which is important in view of decoherence. Furthermore, the scheme is feasible based on current technologies.
基金supported by the National Natural Science Foundation of China (Grant No.10674001)the Program of the Education Department of Anhui Province (Grant No.KJ2007A002)
文摘We propose a unified scheme to implement the optimal 1→ 3economical phase-covariant quantum cloning and optimal 1→3 economical real state cloning with superconducting quantum interference devices (SQUIDs) in a cavity.During this process,no transfer of quantum information between the SQUIDs and cavity is required.The cavity field is only virtually excited.The scheme is insensitive to cavity decay.Therefore,the scheme can be experimentally realized in the range of current cavity QED techniques.
基金supported by the National Natural Science Foundation of China (Grant No 10674001)the Program of the Education Department of Anhui Province of China (Grant No KJ2007A002)
文摘This paper presents a very simple method to derive the explicit transformations of the optimal economical 1 to M phase-covariant cloning. The fidelity of clones reaches the theoretic bound [D＇Ar]ano G M and Macchiavello C 2003 Phys. Rev. A 67 042306]. The derived transformations cover the previous contributions [Delgado Y, Lamata Let al, 2007 Phys. Rev. Lett. 98 150502] in which M must be odd.
文摘By means of cavity-assisted photon interference, a simple scheme is proposed to implement a symmetric economical phase-covariant quantum cloning machine of two remote qubits, with each in a separate cavity. With our present scheme, a high-fidelity cloning machine is realized. Our scheme may be quite useful in terms of distributed quantum information processing.
基金supported by the National Natural Science Foundation of China(Grant Nos.11074002,61073048,and 11104057)the Natural Science Foundationof the Education Department of Anhui Province,China(Grant Nos.KJ2010ZD08 and KJ2012A245)the Postgraduate Program of Huainan NormalUniversity of China
文摘In this paper, we derive the explicit transformations of the optimal 1→3, 4, 5 phase-covariant cloning in three dimensions, and then generalize them to the cases of 1 → M = 3n, 3n ＋ 1, 3n ＋ 2 （n ≥ 1 integer） cloning. The clone fidelities are coincident with the theoretical bounds found.
基金Supported by the Special Funds of the National Natural Science Foundation of China under Grant No. 10947017/A05
文摘We propose an experimentally feasible scheme to implement the economical 1 → M phase-covariant telecloning based on cavity QED. By the resonant interaction of the atoms with cavity field of a high-Q cavity and the different coupling strength between atoms and cavity field, the scheme can generate quantum entanglement channel in one step. What is more, the operation time and steps do not increase with the increase of atoms.
基金National Natural Science Foundation of China under Grant No.10674001the Program of the Education Department of Anhui Province under Grant No.KJ2007A002
文摘We propose an experimentally feasible scheme to implement the optimal asymmetric economical 1→2 phase-covariant quantum cloning in two dimensions based on the cavity QED technique. The protocol is very simple and only two atoms are required. Our scheme is insensitive to the cavity field states and cavity decay. During the processes, the cavity is only virtually excited and it thus greatly prolongs the efficient decoherent time. Therefore, it may be realized in experiment.
基金National Natural Science Foundation under Grant Nos.1.0574022 and 10575022the Natural Science Foundation of Fujian Province under Grant Nos.Z0512006 and A0210014
文摘We propose a simple scheme for the implementation of the ancillary-free 1→3 optimal phase-covariant quantum cloning for x-y equatorial qubits in ion-trap system. In the scheme, the vibrational mode is only virtually excited, which is very important in view of decoherence. The present proposal can be realized based on current available technologies.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 11074002,61073048,and 11104057the Natural Science Foundation of the Education Department of Anhui Province of China under Grant Nos. KJ2010ZD08,KJ2012A245the Postgraduate Program of Huainan Normal University
文摘In this paper,we present the explicit transformations of the optimal 1 → 3,4,5 phase-covariant cloning in 3 dimensions.The cloning fidelities are covered by the theoretical bounds of the optimal 1 → 3k,3k + 1,3k + 2 phase-covariant cloning of qutrits,where k ≥ 1 is the integral [Phys.Rev.A 67(2003) 042306].
