Superconducting quantum bit and Rydberg atom quantum state transfer method and device

Abstract

The invention discloses a superconducting quantum bit and Rydberg atom quantum state transfer method and a superconducting quantum bit and Rydberg atom quantum state transfer device. The superconducting quantum bit and Rydberg atom quantum state transfer method comprises the following steps of: S1, coupling a first superconducting quantum bit of a 50mK refrigeration platform with a superconductingtransmission line cavity of which the two ends are respectively and thermally anchored on the 50mK refrigeration platform and a 1K or 4K refrigeration platform; S2, the superconducting transmission line cavity is coupled with a superconducting planar waveguide cavity or a superconducting planar LC resonant cavity of a 1K or 4K refrigeration platform; S3, coupling a superconducting planar waveguide cavity or a superconducting planar LC resonant cavity of the 1K or 4K refrigeration platform with Rydberg atoms; and S4, extracting a number of hot photons in a coupled cavity system consisting of the superconducting transmission line cavity and the superconducting planar waveguide cavity or the superconducting planar LC resonant cavity by utilizing a second superconducting quantum bit. According to the superconducting quantum bit and Rydberg atom quantum state transfer method, quantum state transfer from superconducting quantum bits of different refrigeration platforms to Rydberg atoms is realized, the influence of hot photons in a coupled cavity system on quantum state transfer is broken through, and high-fidelity quantum state transfer from superconducting quantum bits to Rydberg atoms is realized.

Description

technical field [0001] The invention relates to the technical field of quantum networks, in particular to a method and a device for transferring a superconducting qubit and a Rydberg atom quantum state. Background technique [0002] Both superconducting circuits and Rydberg atoms can be used as qubits. Superconducting circuits as qubits have the advantages of fast operation speed and strong scalability; Rydberg atoms as qubits have advantages such as long coherence time. Quantum state transfer between superconducting qubits and Rydberg atoms, as one of the key technologies for atomic quantum memory, has broad applications in quantum communication, quantum networks, etc. [0003] The quantum state transfer between traditional superconducting qubits and Rydberg atoms is carried out in a refrigeration platform of tens of mK (milliKelvin) in a dilution refrigerator. When the optical window of the refrigerator is shielded, the temperature of the cooling platform can reach 14mK, ...

AI Technical Summary

Problems solved by technology

Affected by the optical window required to prepare cold atoms and the high-power laser required to excite cold atoms into the Rydberg state, mK's cooling platform is difficult to maintain at its lowest temperature, thus affecting the coherence of superconducting qubits Further, the scattered light of the high-power laser required to excite the cold atoms into the Rydberg state will destroy the Cooper pairs and lead to the increase of quasi-particles, thereby limiting the coherence time of superconducting qubits

In addition, the non-uniform gradient magnetic field required to prepare cold atoms will introduce additional magnetic field noise, which will also adversely affect the coherence of superconducting qubits

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