Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

A dephasing sweet spot with enhanced dipolar coupling

Ungerer, Jann H. ; Pally, Alessia ; Bosco, Stefano ; Kononov, Artem ; Sarmah, Deepankar ; Lehmann, Sebastian LU ; Thelander, Claes LU ; Maisi, Ville F. LU ; Scarlino, Pasquale and Loss, Daniel , et al. (2025) In Communications Physics 8(1).
Abstract

Two-level systems (TLSs) are the basic units of quantum computers but face a trade-off between operation speed and coherence due to shared coupling paths. Here, we investigate a TLS given by a singlet-triplet (ST+) transition. We identify a magnetic-field configuration that maximizes dipole coupling while minimizing total dephasing, forming a compromise-free sweet spot that mitigates this fundamental trade-off. The TLS is implemented in a crystal-phase-defined double-quantum dot in an InAs nanowire. Using a superconducting resonator, we measure the spin-orbit interaction (SOI) gap, the spin-photon coupling strength, and the total TLS dephasing rate as a function of the in-plane magnetic-field orientation. Our theoretical description... (More)

Two-level systems (TLSs) are the basic units of quantum computers but face a trade-off between operation speed and coherence due to shared coupling paths. Here, we investigate a TLS given by a singlet-triplet (ST+) transition. We identify a magnetic-field configuration that maximizes dipole coupling while minimizing total dephasing, forming a compromise-free sweet spot that mitigates this fundamental trade-off. The TLS is implemented in a crystal-phase-defined double-quantum dot in an InAs nanowire. Using a superconducting resonator, we measure the spin-orbit interaction (SOI) gap, the spin-photon coupling strength, and the total TLS dephasing rate as a function of the in-plane magnetic-field orientation. Our theoretical description postulates phonons as the dominant noise source. The compromise-free sweet spot originates from the SOI, suggesting that it is not restricted to this material platform but might find applications in any material with SOI. These findings pave the way for enhanced nanomaterial engineering for next-generation qubit technologies.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; ; ; ; and , et al. (More)
; ; ; ; ; ; ; ; ; ; and (Less)
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Communications Physics
volume
8
issue
1
article number
306
publisher
Nature Publishing Group
external identifiers
  • scopus:105011354061
  • pmid:40717727
ISSN
2399-3650
DOI
10.1038/s42005-025-02216-9
language
English
LU publication?
yes
id
ebb5d08c-80a1-449c-b518-166921f61f8c
date added to LUP
2025-10-27 11:45:25
date last changed
2025-11-24 14:19:12
@article{ebb5d08c-80a1-449c-b518-166921f61f8c,
  abstract     = {{<p>Two-level systems (TLSs) are the basic units of quantum computers but face a trade-off between operation speed and coherence due to shared coupling paths. Here, we investigate a TLS given by a singlet-triplet (ST+) transition. We identify a magnetic-field configuration that maximizes dipole coupling while minimizing total dephasing, forming a compromise-free sweet spot that mitigates this fundamental trade-off. The TLS is implemented in a crystal-phase-defined double-quantum dot in an InAs nanowire. Using a superconducting resonator, we measure the spin-orbit interaction (SOI) gap, the spin-photon coupling strength, and the total TLS dephasing rate as a function of the in-plane magnetic-field orientation. Our theoretical description postulates phonons as the dominant noise source. The compromise-free sweet spot originates from the SOI, suggesting that it is not restricted to this material platform but might find applications in any material with SOI. These findings pave the way for enhanced nanomaterial engineering for next-generation qubit technologies.</p>}},
  author       = {{Ungerer, Jann H. and Pally, Alessia and Bosco, Stefano and Kononov, Artem and Sarmah, Deepankar and Lehmann, Sebastian and Thelander, Claes and Maisi, Ville F. and Scarlino, Pasquale and Loss, Daniel and Baumgartner, Andreas and Schönenberger, Christian}},
  issn         = {{2399-3650}},
  language     = {{eng}},
  number       = {{1}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Communications Physics}},
  title        = {{A dephasing sweet spot with enhanced dipolar coupling}},
  url          = {{http://dx.doi.org/10.1038/s42005-025-02216-9}},
  doi          = {{10.1038/s42005-025-02216-9}},
  volume       = {{8}},
  year         = {{2025}},
}