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MON: Monday Contributed Sessions
MON 14: QIP Implementations: Solid-State Devices I
MON 14.1: Vortrag
Montag, 8. September 2025, 16:30–16:45, ZHG002
Fast quantum gates for exchange-only qubits using simultaneous exchange pulses — •Irina Heinz1, Felix Borjans2, Matthew J. Curry2, Roza Kotlyar2, Florian Luthi2, Mateusz T. Mądzik2, Fahd A. Mohiyaddin2, Nathaniel Bishop2, and Guido Burkard1 — 1Department of Physics, University of Konstanz, Konstanz, Germany — 2Intel Technology Research, Intel Corporation, Hillsboro, OR, USA
The benefit of exchange-only qubits compared to other spin qubit types is the universal control using only voltage controlled exchange interactions between neighboring spins. As a compromise, qubit operations have to be constructed from non-orthogonal rotation axes of the Bloch sphere and result in rather long pulsing sequences. We theoretically develop a faster implementation of single-qubit gates using simultaneous exchange pulses and manifests their potential for the construction of two-qubit gates. We introduce faster pulse sequences and show that subsequences on three spins in two-qubit gates could be implemented in fewer steps. We experimentally demonstrate and characterize a simultaneous exchange implementation of X rotations in a SiGe quantum dot device and compare to the state of the art with sequential exchange pulses. Our findings can particularly speed up gate sequences for realistic idle times between sequential pulses and we show that this advantage increases with more interconnectivity of the quantum dots. We further demonstrate how a phase operation can introduce a relative phase between the computational and some of the leakage states, which can be advantageous for the construction of two-qubit gates.
Keywords: spin qubits; exchange-only qubits