Exchange-Coupled Spins for Robust High-Temperature Qubits

Fuente: arXiv
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Main Authors: Chakraborty, Aniruddha, Chowdhury, Md. Fahim F., Niknam, Mohamad, Bouchard, Louis S., Atulasimha, Jayasimha
Format: Preprint
Published: 2025
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author Chakraborty, Aniruddha
Chowdhury, Md. Fahim F.
Niknam, Mohamad
Bouchard, Louis S.
Atulasimha, Jayasimha
author_facet Chakraborty, Aniruddha
Chowdhury, Md. Fahim F.
Niknam, Mohamad
Bouchard, Louis S.
Atulasimha, Jayasimha
contents We show that Heisenberg exchange interactions between the neighboring spins comprising an ensemble spin qubit (E-qubit) can act as an intrinsic error mitigator, increasing gate fidelity even at high temperatures. As an example, the fidelity of a π gate applied to E-qubits above 1 K was studied by tuning the ferromagnetic exchange strength to show an exchange coupled E-qubit exhibits higher fidelity than a single-spin based qubit. We also investigate the coherence properties of E-qubits and find that the coherence time of an E-qubit extends linearly with the number of spins in the ensemble. This suggests that exchange interactions effectively suppress decoherence induced by thermal noise, achieving a coherence time greater than 1 ms at 1 K with an ensemble of only seven spins. Additionally, the ferromagnetic isotropic exchange prevents fidelity loss induced by spatial field gradients/inhomogeneity in Zeeman and/or control fields. Therefore, exchange-coupled spin qubits could enable fault-tolerant quantum operations and long-coherence times at elevated temperatures (>1 K).
format Preprint
id arxiv_https___arxiv_org_abs_2503_12071
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Exchange-Coupled Spins for Robust High-Temperature Qubits
Chakraborty, Aniruddha
Chowdhury, Md. Fahim F.
Niknam, Mohamad
Bouchard, Louis S.
Atulasimha, Jayasimha
Mesoscale and Nanoscale Physics
Quantum Physics
We show that Heisenberg exchange interactions between the neighboring spins comprising an ensemble spin qubit (E-qubit) can act as an intrinsic error mitigator, increasing gate fidelity even at high temperatures. As an example, the fidelity of a π gate applied to E-qubits above 1 K was studied by tuning the ferromagnetic exchange strength to show an exchange coupled E-qubit exhibits higher fidelity than a single-spin based qubit. We also investigate the coherence properties of E-qubits and find that the coherence time of an E-qubit extends linearly with the number of spins in the ensemble. This suggests that exchange interactions effectively suppress decoherence induced by thermal noise, achieving a coherence time greater than 1 ms at 1 K with an ensemble of only seven spins. Additionally, the ferromagnetic isotropic exchange prevents fidelity loss induced by spatial field gradients/inhomogeneity in Zeeman and/or control fields. Therefore, exchange-coupled spin qubits could enable fault-tolerant quantum operations and long-coherence times at elevated temperatures (>1 K).
title Exchange-Coupled Spins for Robust High-Temperature Qubits
topic Mesoscale and Nanoscale Physics
Quantum Physics
url https://arxiv.org/abs/2503.12071