ENTANGLED STATE PREPARATION METHOD AND DEVICE BASED ON SUPERCONDUCTING QUBIT AND RYDBERG ATOM

摘要

An entangled state preparation method and device based on a superconducting qubit and a Rydberg atom. The method comprises: performing resonance coupling on a superconducting qubit and a selected mode of a superconducting transmission line cavity, performing, at the same time, resonance coupling on two Rydberg states of a Rydberg atom and a superconducting planar waveguide cavity/a superconducting planar LC resonant cavity, and performing resonance coupling on the superconducting planar waveguide cavity/the superconducting planar LC resonant cavity and the selected mode of the superconducting transmission line cavity; adjusting the coupling strength g1 between the superconducting qubit and the superconducting transmission line cavity, and adjusting the coupling strength g2 between the Rydberg atom and the superconducting planar waveguide cavity/the superconducting planar LC resonant cavity, such that the coupling strengths and the coupling strength J between the superconducting transmission line cavity and the superconducting planar waveguide cavity/the superconducting planar LC resonant cavity satisfy the relationship in (equation I); and by means of two strong microwave drive fields, realizing an unconventional geometric quantum gate, and completing the preparation of the maximum entangled state. The impact of a laser field and a magnetic field required by a Rydberg atom, and the radiation cooling of a superconducting coaxial cable on the coherence of a superconducting qubit can be reduced.