Demonstration of an always-on exchange-only spin qubit

• URL: http://arxiv.org/abs/2508.01033v1
• Date: Fri, 01 Aug 2025 19:20:09 GMT
• Title: Demonstration of an always-on exchange-only spin qubit
• Authors: Joseph D. Broz, Jesse C. Hoke, Edwin Acuna, Jason R. Petta,
• Abstract summary: We demonstrate high-fidelity quantum control of an always-on exchange-only qubit, operated using simultaneous exchange pulses.<n> Extensions of this work may enable more efficient EO two-qubit entangling gates as well as the implementation of native $i$-Toffoli gates in Loss-DiVincenzo single-spin qubits.
• Score: 0.027042267806481293
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: In conventional exchange-only (EO) spin qubit demonstrations, quantum gates have been implemented using sequences of individually pulsed pairwise exchange interactions with only one exchange coupling active at a time. Alternatively, multiple non-commuting exchange interactions can be pulsed simultaneously, reducing circuit depths and providing protection against leakage. We demonstrate high-fidelity quantum control of an always-on exchange-only (AEON) qubit, operated using simultaneous exchange pulses in a triangular quantum dot (QD) array. We use blind randomized benchmarking to characterize the performance of the full AEON single-qubit Clifford gate set, achieving an average Clifford gate fidelity $F_{\rm C1}$ = 99.86\%. Extensions of this work may enable more efficient EO two-qubit entangling gates as well as the implementation of native $i$-Toffoli gates in Loss-DiVincenzo single-spin qubits.

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