Deterministic Loading of Microwaves onto an Artificial Atom Using a Time-Reversed Waveform.

Lin, Wei-Ju; Lu, Yong; Wen, Ping Yi; Cheng, Yu-Ting; Lee, Ching-Ping; Lin, Kuan Ting; Chiang, Kuan Hsun; Hsieh, Ming Che et al. · Nano Lett · 2022

basic_science · Level V

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Abstract

Loading quantum information deterministically onto a quantum node is an important step toward a quantum network. Here, we demonstrate that coherent-state microwave photons with an optimal temporal waveform can be efficiently loaded onto a single superconducting artificial atom in a semi-infinite one-dimensional (1D) transmission-line waveguide. Using a weak coherent state (the number of photons (<i>N</i>) contained in the pulse ≪1) with an exponentially rising waveform, whose time constant matches the decoherence time of the artificial atom, we demonstrate a loading efficiency of 94.2% ± 0.7% from 1D semifree space to the artificial atom. The high loading efficiency is due to time-reversal symmetry: the overlap between the incoming wave and the time-reversed emitted wave is up to 97.1% ± 0.4%. Our results open up promising applications in realizing quantum networks based on waveguide quantum electrodynamics.