Rapid High-Fidelity Spin-State Readout in Si/Si-Ge Quantum Dots via rf Reflectometry | doi.page

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Rapid High-Fidelity Spin-State Readout in Si/Si-Ge Quantum Dots via rf Reflectometry

Physical Review Applied2020Vol. 13(2)

Citations Over TimeTop 10% of 2020 papers

Elliot J. Connors, JJ Nelson, John M. Nichol

Abstract

Silicon spin qubits show great promise as a scalable qubit platform for fault-tolerant quantum computing. However, fast high-fidelity readout of charge and spin states, which is required for quantum error correction, has remained elusive. Radio-frequency reflectometry enables rapid high-fidelity readout of $\mathrm{Ga}\mathrm{As}$ spin qubits, but the large capacitances between accumulation gates and the underlying two-dimensional electron gas in accumulation-mode $\mathrm{Si}$ quantum-dot devices, as well as the relatively low two-dimensional electron gas mobilities, have made radio-frequency reflectometry challenging in these platforms. In this work, we implement radio-frequency reflectometry in a $\mathrm{Si}$/$\mathrm{Si}\text{\ensuremath{-}}\mathrm{Ge}$ quantum-dot device with overlapping gates by making minor device-level changes that eliminate these challenges. We demonstrate charge-state readout with a fidelity above $99.9\mathrm{%}$ in an integration time of $300\phantom{\rule{0.2em}{0ex}}\mathrm{ns}$. We measure the singlet and triplet states of a double quantum dot via both conventional Pauli spin blockade and a charge latching mechanism, and we achieve maximum fidelities of $82.9$ and $99.0\mathrm{%}$ in $2.08$- and $1.6$-$\ensuremath{\mu}\mathrm{s}$ integration times, respectively. We also use radio-frequency reflectometry to perform single-shot readout of single-spin states via spin-selective tunneling in microsecond-scale integration times.

Citations Over TimeTop 10% of 2020 papers

Abstract

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