Universal logic with encoded spin qubits in silicon

• URL: http://arxiv.org/abs/2202.03605v1
• Date: Tue, 8 Feb 2022 02:23:46 GMT
• Title: Universal logic with encoded spin qubits in silicon
• Authors: Aaron J. Weinstein, Matthew D. Reed, Aaron M. Jones, Reed W. Andrews, David Barnes, Jacob Z. Blumoff, Larken E. Euliss, Kevin Eng, Bryan Fong, Sieu D. Ha, Daniel R. Hulbert, Clayton Jackson, Michael Jura, Tyler E. Keating, Joseph Kerckhoff, Andrey A. Kiselev, Justine Matten, Golam Sabbir, Aaron Smith, Jeffrey Wright, Matthew T. Rakher, Thaddeus D. Ladd and Matthew G. Borselli
• Abstract summary: Qubits encoded in a decoherence-free subsystem and realized in exchange-coupled silicon quantum dots are promising candidates for fault-tolerant quantum computing. Key difficulties are that encoded entangling gates require a large number of control pulses and high-yielding quantum dot arrays. Here we show a device made using the single-layer etch-defined gate architecture that achieves both the required functional yield needed for full control and the coherence necessary for thousands of exchange pulses to be applied.
• Score: 1.5796098351442824
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Qubits encoded in a decoherence-free subsystem and realized in exchange-coupled silicon quantum dots are promising candidates for fault-tolerant quantum computing. Benefits of this approach include excellent coherence, low control crosstalk, and configurable insensitivity to certain error sources. Key difficulties are that encoded entangling gates require a large number of control pulses and high-yielding quantum dot arrays. Here we show a device made using the single-layer etch-defined gate electrode architecture that achieves both the required functional yield needed for full control and the coherence necessary for thousands of calibrated exchange pulses to be applied. We measure an average two-qubit Clifford fidelity of $97.1 \pm 0.2\%$ with randomized benchmarking. We also use interleaved randomized benchmarking to demonstrate the controlled-NOT gate with $96.3 \pm 0.7\%$ fidelity, SWAP with $99.3 \pm 0.5\%$ fidelity, and a specialized entangling gate that limits spreading of leakage with $93.8 \pm 0.7\%$ fidelity.

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