Scientific Highlights

Proposal for generating complex microwave graph states using superconducting circuits

March 16, 2022

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Figure: Generation circuits (top panels) and the microwave (MW) state quality for fixed frequency (middle panels) and tunable frequency (bottom panels). For MW 2D cluster states (left column), we find the number of photons with fidelity 0.8.

Accomplishment

We developed a protocol for the generation of microwave resource states. These are entangled ‘graph states’ that can be emitted from superconducting circuits. We calculated the fidelity of the resulting states, assuming current experimental parameters, and identified the main factors that limit performance. This work serves as a blueprint for experiments.

Significance and Impact

Microwave graph states are significant for robust quantum communication between superconducting quantum processors in a distributed architecture. The encodings we consider protect against loss.

Details

We designed generation protocols for 2D lattice and tree-like microwave graph states with realistic experimental parameters. We compared the performance using fixed-frequency versus tunable-frequency transmon qubits for different photonic qubit encodings. For both types of transmons, a 2D graph state with size 2×8 can be generated with fidelity 0.8, while the tree graph state (see the left column of the figure) can be generated with fidelity 0.87. We identified the main factors that limit the state fidelities for further improving the microwave state fidelities.

Authors: Chenxu Liu, Edwin Barnes, Sophia Economou
arXiv: 2201.00836
Work performed at Virginia Tech, Blacksburg, VA, USA

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