An unknown quantum state is prohibited from perfect cloning due to the principles of quantum mechanics,while approximate cloning of an unknown quantum state can be achieved by constructing quantum cloning machines.In ...An unknown quantum state is prohibited from perfect cloning due to the principles of quantum mechanics,while approximate cloning of an unknown quantum state can be achieved by constructing quantum cloning machines.In the continuous variable regime,to effectively improve the cloning fidelity,an N+N'→M+M'phaseconjugate inputs(PCI)quantum cloning scheme is proposed based on an optical parametric amplifier and beam splitter network.However,due to the difficulties in constructing an optical parametric amplifier approaching the quantum noise limit,such quantum cloning scheme has not been experimentally realized.In this work,we present all-optical N+N'→M+M'PCI quantum cloning of coherent states by utilizing a phase-sensitive amplifier based on a four-wave mixing process.In particular,we experimentally realize deterministic all-optical1+1→M+M'(M=M'=2,4)and 2+2→M+M'(M=M'=3,4,6,8)PCI quantum cloning.The maximum cloning fidelities experimentally achieved are 96.76%±0.57%and 96.80%±0.58%in the2+2→3+3 case,which are the maximum cloning fidelities in deterministic continuous variable quantum cloning,to our knowledge.Our results provide an effective scheme for enhancing cloning fidelity and can find applications in achieving high-fidelity quantum information protocols.展开更多
基金National Natural Science Foundation of China(12225404,12434014,11874155,91436211,11374104,12174110,12474357,12574390,12521003)Innovation Program for Quantum Science and Technology(2024ZD0-302402)+10 种基金Innovation Program of Shanghai Municipal Education Commission(2021-01-07-00-08-E00100)Program of Shanghai Academic Research Leader(22XD1400700)Basic Research Project in Quantum Science of Shanghai Action Plan for Science Technology and Innovation(24LZ1400700)Basic Research Project of Shanghai Science and Technology Commission(20JC1416100)Natural Science Foundation of Shanghai(17ZR1442900,24ZR141-8700)Minhang Leading Talents(201971)Fundamental Research Funds for the Central UniversitiesShanghai Sailing Program(21YF1410800)Natural Science Foundation of Chongqing Municipality(CSTB2022NSCQ-MSX0893)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)111 Project(B12024)。
文摘An unknown quantum state is prohibited from perfect cloning due to the principles of quantum mechanics,while approximate cloning of an unknown quantum state can be achieved by constructing quantum cloning machines.In the continuous variable regime,to effectively improve the cloning fidelity,an N+N'→M+M'phaseconjugate inputs(PCI)quantum cloning scheme is proposed based on an optical parametric amplifier and beam splitter network.However,due to the difficulties in constructing an optical parametric amplifier approaching the quantum noise limit,such quantum cloning scheme has not been experimentally realized.In this work,we present all-optical N+N'→M+M'PCI quantum cloning of coherent states by utilizing a phase-sensitive amplifier based on a four-wave mixing process.In particular,we experimentally realize deterministic all-optical1+1→M+M'(M=M'=2,4)and 2+2→M+M'(M=M'=3,4,6,8)PCI quantum cloning.The maximum cloning fidelities experimentally achieved are 96.76%±0.57%and 96.80%±0.58%in the2+2→3+3 case,which are the maximum cloning fidelities in deterministic continuous variable quantum cloning,to our knowledge.Our results provide an effective scheme for enhancing cloning fidelity and can find applications in achieving high-fidelity quantum information protocols.
