arXiv:1610.05995 · Scientific Reports

Transferring arbitrary d-dimensional quantum states of a superconducting transmon qudit in circuit QED

Tong Liu, Qi-Ping Su, Jin-Hu Yang, Yu Zhang, Shao-Jie Xiong, Jin-Ming Liu, Chui-Ping Yang

Published Jul 26, 2017• 17 citations

Abstract

A qudit (d-level quantum system) has a large Hilbert space and thus can be used to achieve many quantum information and communication tasks. Here, we propose a method to transfer arbitrary d-dimensional quantum states (known or unknown) between two superconducting transmon qudits coupled to a single cavity. The state transfer can be performed by employing resonant interactions only. In addition, quantum states can be deterministically transferred without measurement. Numerical simulations show that high-fidelity transfer of quantum states between two superconducting transmon qudits (d ≤ 5) is feasible with current circuit QED technology. This proposal is quite general and can be applied to accomplish the same task with natural or artificial atoms of a ladder-type level structure coupled to a cavity or resonator.

DOI: 10.1038/s41598-017-07225-5

Related papers

Efficient transfer of an arbitrary qutrit state in circuit quantum electrodynamics

Tong Liu, Shao-Jie Xiong, Xiao-Zhi Cao +2 more

Compared with a qubit, a qutrit (i.e., three-level quantum system) has a larger Hilbert space and thus can be used to encode more information in quantum information processing and communication. Here, we propose a method to transfer an arbitrary quantum state between two flux qutrits coupled to two resonators. This scheme is simple because it only requires two basic operations. The state-transfer operation can be performed fast because only resonant interactions are used. Numerical simulations show that the high-fidelity transfer of quantum states between the two qutrits is feasible with current circuit-QED technology. This scheme is quite general and can be applied to accomplish the same task for other solid-state qutrits coupled to resonators.

arXiv:1610.02679Optics LettersNov 23, 201519 citations

Transferring entangled states of photonic cat-state qubits in circuit QED

Tong Liu, Zhen-Fei Zheng, Yu Zhang +2 more

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.

arXiv:2003.14168Frontiers of PhysicsJan 13, 202013 citations

Transferring quantum entangled states of photonic qubits via a quantum switch

Wen-Hao Kong, Jia-Heng Ni, Yifan Kang +5 more

The controlled transfer of quantum entangled states is a fascinating topic in quantum physics, and has potential applications in fields such as quantum network communication, distributed quantum information processing, and development of quantum functional devices. This study focuses on a circuit quantum electrodynamics (QED) system, comprising an input port, two output ports, and a quantum switch. The input port or each output port contains n microwave cavities. The switch is a superconducting transmon qutrit (three-level quantum system). The vacuum and single-photon states in each cavity encode a photonic qubit. We demonstrate that the single-excitation symmetric (SES) entangled state of n photonic qubits can be transferred from the n cavities at the input port to the n cavities at either of the two output ports, controlled by the switch. Remarkably, the operational time decreases as the number n increases. The only use of qutrit-cavity resonant interaction enables rapid quantum state transfer while effectively suppressing system decoherence. This proposal can be used to achieve the controlled transfer of both Bell states and W states of photonic qubits via a quantum switch. To validate the experimental feasibility, we numerically simulate two scenarios: (i) transferring the Bell state of two photonic qubits, and (ii) transferring the W state of three photonic qubits. This proposal may be extended to accomplish the same task in other physical systems, where the switch is implemented with a three-level artificial atom of different types while each cavity is a microwave or optical cavity.

Frontiers of PhysicsJan 1, 20260 citations

Transferring quantum entangled states between multiple single-photon-state qubits and coherent-state qubits in circuit QED

Qi-Ping Su, Hanyu Zhang, Chui‐Ping Yang

We present a way to transfer maximally- or partially-entangled states of n single-photon-state (SPS) qubits onto n coherent-state (CS) qubits, by employing 2 n microwave 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 2 n microwave or optical cavities.

arXiv:2107.04203Frontiers of PhysicsJul 31, 202110 citations

Transfer of arbitrary quantum states between separated superconducting cavities via an ensemble of nitrogen-vacancy centers

Jin Xia Xu, Tong Liu

Transfer of quantum states between distant nodes is one of the most important preconditions for realizing large-scale quantum information processing. We here propose two ways to transfer an arbitrary quantum state between two separated superconducting cavities coupled to an ensemble of nitrogen-vacancy centers (NV ensemble). By using the double-swap scheme and theory of the dispersive regime, quantum states can be deterministically transferred between two superconducting cavities. With current hybrid circuit QED technology, the numerical simulations are performed to demonstrate that the single-photon state and cat state can be high-fidelity transferred between two superconducting cavities.

Results in PhysicsDec 12, 20227 citations

Transfer of quantum entangled states between superconducting qubits and microwave field qubits

Tong Liu, Bao-qing Guo, Y. H. Zhou +4 more

Transferring entangled states between matter qubits and microwave-field (or optical-field) qubits is of fundamental interest in quantum mechanics and necessary in hybrid quantum information processing and quantum communication. We here propose a way for transferring entangled states between superconducting qubits (matter qubits) and microwave-field qubits. This proposal is realized by a system consisting of multiple superconducting qutrits and microwave cavities. Here, “qutrit” refers to a three-level quantum system with the two lowest levels encoding a qubit while the third level acting as an auxiliary state. In contrast, the microwave-field qubits are encoded with coherent states of microwave cavities. Because the third energy level of each qutrit is not populated during the operation, decoherence from the higher energy levels is greatly suppressed. The entangled states can be deterministically transferred because measurement on the states is not needed. The operation time is independent of the number of superconducting qubits or microwave-field qubits. In addition, the architecture of the circuit system is quite simple because only a coupler qutrit and an auxiliary cavity are required. As an example, our numerical simulations show that high-fidelity transfer of entangled states from two superconducting qubits to two microwave-field qubits is feasible with present circuit QED technology. This proposal is quite general and can be extended to transfer entangled states between other matter qubits (e.g., atoms, quantum dots, and NV centers) and microwave- or optical-field qubits encoded with coherent states.

Frontiers of PhysicsJul 9, 20226 citations