Parity and singlet-triplet high fidelity readout in a silicon double quantum dot at 0.5 K

TL;DR

This paper demonstrates high-fidelity singlet-triplet and parity spin readout in a silicon double quantum dot at 0.5 K, achieving over 99.9% fidelity in a 20 microsecond readout time.

Contribution

It introduces a method for high-fidelity spin state readout and initialization in silicon quantum dots at relatively high temperature, advancing quantum dot qubit technology.

Findings

Achieved >99.9% fidelity in 20 microseconds for spin readout.

Successfully initialized singlet states with >99% fidelity.

Maintained spin state separation with approximately 95.6% fidelity.

Abstract

We demonstrate singlet-triplet readout and parity readout allowing to distinguish T0 and the polarized triplet states. We achieve high fidelity spin readout with an average fidelity above $99.9\%$ for a readout time of $20~\mu$s and $99\%$ for $4~\mu$s at a temperature of $0.5~K$. We initialize a singlet state in a single dot with a fidelity higher than $99\%$ and separate the two electrons while keeping the same spin state with $a \approx 95.6\%$ fidelity.