We present a way to transfer maximally-or partially-entangled states of n single-photon-state(SPS)qubits onto ncoherent-state(CS)qubits,by employing 2nmicrowave cavities coupled to a superconducting flux qutrit.The tw...We present a way to transfer maximally-or partially-entangled states of n single-photon-state(SPS)qubits onto ncoherent-state(CS)qubits,by employing 2nmicrowave cavities coupled to a superconducting flux qutrit.The two logic states of a SPS qubit here are represented by the vacuum state and the single-photon state of a cavity,while the two logic states of a CS qubit are encoded with two coherent states of a cavity.Because of using only one superconducting qutrit as the coupler,the circuit architecture is significantly simplified.The operation time for the state transfer does not increase with the increasing of the number of qubits.When the dissipation of the system is negligible,the quantum state can be transferred in a deterministic way since no measurement is required.Furthermore,the higher-energy intermediate level of the coupler qutrit is not excited during the entire operation and thus decoherence from the qutrit is greatly suppressed.As a specific example,we numerically demonstrate that the high-fidelity transfer of a Bell state of two SPS qubits onto two CS qubits is achievable within the present-day circuit QED technology.Finally,it is worthy to note that when the dissipation is negligible,entangled states of n CS qubits can be transferred back onto n SPS qubits by performing reverse operations.This proposal is quite general and can be extended to accomplish the same task,by employing a natural or artificial atom to couple 2nmicrowave or optical cavities.展开更多
基金This work was partly supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.11074062,11374083,and 11774076)the Key-Area Research and Development Program of GuangDong province(Grant No.2018B030326001)the NKRDP of China(Grant No.2016YFA0301802).
文摘We present a way to transfer maximally-or partially-entangled states of n single-photon-state(SPS)qubits onto ncoherent-state(CS)qubits,by employing 2nmicrowave cavities coupled to a superconducting flux qutrit.The two logic states of a SPS qubit here are represented by the vacuum state and the single-photon state of a cavity,while the two logic states of a CS qubit are encoded with two coherent states of a cavity.Because of using only one superconducting qutrit as the coupler,the circuit architecture is significantly simplified.The operation time for the state transfer does not increase with the increasing of the number of qubits.When the dissipation of the system is negligible,the quantum state can be transferred in a deterministic way since no measurement is required.Furthermore,the higher-energy intermediate level of the coupler qutrit is not excited during the entire operation and thus decoherence from the qutrit is greatly suppressed.As a specific example,we numerically demonstrate that the high-fidelity transfer of a Bell state of two SPS qubits onto two CS qubits is achievable within the present-day circuit QED technology.Finally,it is worthy to note that when the dissipation is negligible,entangled states of n CS qubits can be transferred back onto n SPS qubits by performing reverse operations.This proposal is quite general and can be extended to accomplish the same task,by employing a natural or artificial atom to couple 2nmicrowave or optical cavities.
