Quantum Fourier transform is realized by the Hadamard gate in a quantum computer, which can also be considered as a Hadamard transform. We introduce the Hadamard transformed photon-added coherent state （HTPACS）, whi...Quantum Fourier transform is realized by the Hadamard gate in a quantum computer, which can also be considered as a Hadamard transform. We introduce the Hadamard transformed photon-added coherent state （HTPACS）, which is obtained by letting the photon-added coherent state （PACS） across the quantum Hadamard gate, from this result. It is found that the HTPACS can be considered as a coordinate-momentum mutual exchanging followed by a squeezing transform of the PACS. In addition, the non-classical statistical properties of HTPACS, such as squeezing coefficient, Mandel parameter, etc., are also discussed.展开更多
Non-classical states of light,which include squeezed and entangled states of light,are the cornerstone of quantum mechanics and quantum information sciences.To date,non-classical states of light with much higher quali...Non-classical states of light,which include squeezed and entangled states of light,are the cornerstone of quantum mechanics and quantum information sciences.To date,non-classical states of light with much higher quality than before are required to develop high-fidelity quantum information processing and high-precision quantum metrology.Squeezed and entangled states with approximately 10 dB noise below the corresponding shot noise limit have been generated using a series of methods,which means that the noise variance reaches a few percent of the vacuum noise.Quantum teleportation,which means transferring an unknown quantum state from a sending station to a distant receiving station supported by entangled states,is the foundation of quantum computation and quantum communication networks.Quantum teleportation in continuous variable regions is unconditional because the entangled states used are always deterministic.The quantum teleportation distance was recently extended to the order of kilometers,which paves the way for constructing a practical quantum information network.展开更多
We propose a method for transferring quantum entangled states of two photonic cat-state qubits(cqubits)from two microwave cavities to the other two microwave cavities.This proposal is realized by using four microwave ...We propose a method for transferring quantum entangled states of two photonic cat-state qubits(cqubits)from two microwave cavities to the other two microwave cavities.This proposal is realized by using four microwave cavities coupled to a superconducting flux qutrit.Because of using four cavities with different frequencies,the inter-cavity crosstalk is significantly reduced.Since only one coupler qutrit is used,the circuit resource is minimized.The entanglement transfer is completed with a singlestep operation only,thus this proposal is quite simple.The third energy level of the coupler qutrit is not populated during the state transfer,therefore decoherence from the higher energy level is greatly suppressed.Our numerical simulations show that high-fidelity transfer of two-cqubit entangled states from two transmission line resonators to the other two transmission line resonators is feasible with current circuit QED technology.This proposal is universal and can be applied to accomplish the same task in a wide range of physical systems,such as four microwave or optical cavities,which are coupled to a natural or artificial three-level atom.展开更多
基金Project supported by the Natural Science Foundation of the Anhui Provincial Higher Education Institutions of China (Grant Nos.KJ2011Z339 and KJ2011Z359)
文摘Quantum Fourier transform is realized by the Hadamard gate in a quantum computer, which can also be considered as a Hadamard transform. We introduce the Hadamard transformed photon-added coherent state （HTPACS）, which is obtained by letting the photon-added coherent state （PACS） across the quantum Hadamard gate, from this result. It is found that the HTPACS can be considered as a coordinate-momentum mutual exchanging followed by a squeezing transform of the PACS. In addition, the non-classical statistical properties of HTPACS, such as squeezing coefficient, Mandel parameter, etc., are also discussed.
基金The work was supported by the National Natural Science Foundation of China(Grants Nos.61925503,61775127,11654002,and 11834010)the Key Project of the National Key R&D program of China(Grant No.2016YFA0301402)the Program for the Innovative Talents of Higher Education Institutions of Shanxi,the Program for Sanjin Scholars of Shanxi Province,and the fund for Shanxi”1331 Project”Key Subjects Construction.
文摘Non-classical states of light,which include squeezed and entangled states of light,are the cornerstone of quantum mechanics and quantum information sciences.To date,non-classical states of light with much higher quality than before are required to develop high-fidelity quantum information processing and high-precision quantum metrology.Squeezed and entangled states with approximately 10 dB noise below the corresponding shot noise limit have been generated using a series of methods,which means that the noise variance reaches a few percent of the vacuum noise.Quantum teleportation,which means transferring an unknown quantum state from a sending station to a distant receiving station supported by entangled states,is the foundation of quantum computation and quantum communication networks.Quantum teleportation in continuous variable regions is unconditional because the entangled states used are always deterministic.The quantum teleportation distance was recently extended to the order of kilometers,which paves the way for constructing a practical quantum information network.
基金the Key-Area Research and Development Program of GuangDong Province(Grant No.2018B030326001)the National Natural Science Foundation of China(NSFC)(Grant Nos.11074062,11374083,and 11774076)+1 种基金the NKRDP of China(Grant No.2016YFA0301802)the Jiangxi Natural Science Foundation(Grant No.20192ACBL20051).
文摘We propose a method for transferring quantum entangled states of two photonic cat-state qubits(cqubits)from two microwave cavities to the other two microwave cavities.This proposal is realized by using four microwave cavities coupled to a superconducting flux qutrit.Because of using four cavities with different frequencies,the inter-cavity crosstalk is significantly reduced.Since only one coupler qutrit is used,the circuit resource is minimized.The entanglement transfer is completed with a singlestep operation only,thus this proposal is quite simple.The third energy level of the coupler qutrit is not populated during the state transfer,therefore decoherence from the higher energy level is greatly suppressed.Our numerical simulations show that high-fidelity transfer of two-cqubit entangled states from two transmission line resonators to the other two transmission line resonators is feasible with current circuit QED technology.This proposal is universal and can be applied to accomplish the same task in a wide range of physical systems,such as four microwave or optical cavities,which are coupled to a natural or artificial three-level atom.
