Two-qubit sweet spots for capacitively coupled exchange-only spin qubits

The implementation of high fidelity two-qubit gates is a bottleneck in the progress toward universal quantum computation in semiconductor quantum dot qubits. We study capacitive coupling between two triple quantum dot spin qubits encoded in the S = 1/2, Sz = −1/2 decoherence-free subspace—the exchan...

Full description

Saved in:
Bibliographic Details
Main Authors: Feng, MengKe, Zaw, Lin Htoo, Koh, Teck Seng
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2021
Subjects:
Online Access:https://hdl.handle.net/10356/152833
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
id sg-ntu-dr.10356-152833
record_format dspace
spelling sg-ntu-dr.10356-1528332023-02-28T19:54:42Z Two-qubit sweet spots for capacitively coupled exchange-only spin qubits Feng, MengKe Zaw, Lin Htoo Koh, Teck Seng School of Physical and Mathematical Sciences Science::Physics Quantum Mechanics Qubits The implementation of high fidelity two-qubit gates is a bottleneck in the progress toward universal quantum computation in semiconductor quantum dot qubits. We study capacitive coupling between two triple quantum dot spin qubits encoded in the S = 1/2, Sz = −1/2 decoherence-free subspace—the exchange-only (EO) spin qubits. We report exact gate sequences for CPHASE and CNOT gates, and demonstrate theoretically, the existence of multiple two-qubit sweet spots (2QSS) in the parameter space of capacitively coupled EO qubits. Gate operations have the advantage of being all-electrical, but charge noise that couple to electrical parameters of the qubits cause decoherence. Assuming noise with a 1/f spectrum, two-qubit gate fidelities and times are calculated, which provide useful information on the noise threshold necessary for fault-tolerance. We study two-qubit gates at single and multiple parameter 2QSS. In particular, for two existing EO implementations—the resonant exchange (RX) and the always-on exchange-only (AEON) qubits—we compare two-qubit gate fidelities and times at positions in parameter space where the 2QSS are simultaneously single-qubit sweet spots (1QSS) for the RX and AEON. These results provide a potential route to the realization of high fidelity quantum computation. Ministry of Education (MOE) Nanyang Technological University Published version M.K.F. was supported by a Singapore Ministry of Education AcRF Tier 1 grant (RG177/ 16), and acknowledges useful discussions with Jun Yoneda. L.H.Z. was supported by the SGUnited program (CP0002392). We thank the Nanyang Technological University (NTU) High Performance Computing Center for computing support, and the Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, NTU, for financial support. 2021-10-07T02:56:46Z 2021-10-07T02:56:46Z 2021 Journal Article Feng, M., Zaw, L. H. & Koh, T. S. (2021). Two-qubit sweet spots for capacitively coupled exchange-only spin qubits. Npj Quantum Information, 7, 112-. https://dx.doi.org/10.1038/s41534-021-00449-4 2056-6387 https://hdl.handle.net/10356/152833 10.1038/s41534-021-00449-4 2-s2.0-85110677758 7 112 en RG177/ 16 CP0002392 npj Quantum Information 10.21979/N9/TYUUVS © 2021 The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons. org/licenses/by/4.0/. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Science::Physics
Quantum Mechanics
Qubits
spellingShingle Science::Physics
Quantum Mechanics
Qubits
Feng, MengKe
Zaw, Lin Htoo
Koh, Teck Seng
Two-qubit sweet spots for capacitively coupled exchange-only spin qubits
description The implementation of high fidelity two-qubit gates is a bottleneck in the progress toward universal quantum computation in semiconductor quantum dot qubits. We study capacitive coupling between two triple quantum dot spin qubits encoded in the S = 1/2, Sz = −1/2 decoherence-free subspace—the exchange-only (EO) spin qubits. We report exact gate sequences for CPHASE and CNOT gates, and demonstrate theoretically, the existence of multiple two-qubit sweet spots (2QSS) in the parameter space of capacitively coupled EO qubits. Gate operations have the advantage of being all-electrical, but charge noise that couple to electrical parameters of the qubits cause decoherence. Assuming noise with a 1/f spectrum, two-qubit gate fidelities and times are calculated, which provide useful information on the noise threshold necessary for fault-tolerance. We study two-qubit gates at single and multiple parameter 2QSS. In particular, for two existing EO implementations—the resonant exchange (RX) and the always-on exchange-only (AEON) qubits—we compare two-qubit gate fidelities and times at positions in parameter space where the 2QSS are simultaneously single-qubit sweet spots (1QSS) for the RX and AEON. These results provide a potential route to the realization of high fidelity quantum computation.
author2 School of Physical and Mathematical Sciences
author_facet School of Physical and Mathematical Sciences
Feng, MengKe
Zaw, Lin Htoo
Koh, Teck Seng
format Article
author Feng, MengKe
Zaw, Lin Htoo
Koh, Teck Seng
author_sort Feng, MengKe
title Two-qubit sweet spots for capacitively coupled exchange-only spin qubits
title_short Two-qubit sweet spots for capacitively coupled exchange-only spin qubits
title_full Two-qubit sweet spots for capacitively coupled exchange-only spin qubits
title_fullStr Two-qubit sweet spots for capacitively coupled exchange-only spin qubits
title_full_unstemmed Two-qubit sweet spots for capacitively coupled exchange-only spin qubits
title_sort two-qubit sweet spots for capacitively coupled exchange-only spin qubits
publishDate 2021
url https://hdl.handle.net/10356/152833
_version_ 1759858316166561792