---
_id: '14517'
abstract:
- lang: eng
text: 'State-of-the-art transmon qubits rely on large capacitors, which systematically
improve their coherence due to reduced surface-loss participation. However, this
approach increases both the footprint and the parasitic cross-coupling and is
ultimately limited by radiation losses—a potential roadblock for scaling up quantum
processors to millions of qubits. In this work we present transmon qubits with
sizes as low as 36 × 39 µm2 with 100-nm-wide vacuum-gap capacitors that are micromachined
from commercial silicon-on-insulator wafers and shadow evaporated with aluminum.
We achieve a vacuum participation ratio up to 99.6% in an in-plane design that
is compatible with standard coplanar circuits. Qubit relaxationtime measurements
for small gaps with high zero-point electric field variance of up to 22 V/m reveal
a double exponential decay indicating comparably strong qubit interaction with
long-lived two-level systems. The exceptionally high selectivity of up to 20 dB
to the superconductor-vacuum interface allows us to precisely back out the sub-single-photon
dielectric loss tangent of aluminum oxide previously exposed to ambient conditions.
In terms of future scaling potential, we achieve a ratio of qubit quality factor
to a footprint area equal to 20 µm−2, which is comparable with the highest T1
devices relying on larger geometries, a value that could improve substantially
for lower surface-loss superconductors. '
acknowledged_ssus:
- _id: NanoFab
acknowledgement: "This work was supported by the Austrian Science Fund (FWF) through
BeyondC (F7105), the European Research Council under Grant Agreement No. 758053
(ERC StG QUNNECT) and a NOMIS foundation research grant. M.Z. was the recipient
of a SAIA scholarship, E.R. of\r\na DOC fellowship of the Austrian Academy of Sciences,
and M.P. of a Pöttinger scholarship at IST Austria. S.B. acknowledges support from
Marie Skłodowska Curie Program No. 707438 (MSC-IF SUPEREOM). J.M.F. acknowledges
support from the Horizon Europe Program HORIZON-CL4-2022-QUANTUM-01-SGA via Project
No. 101113946 OpenSuperQPlus100 and the ISTA Nanofabrication Facility."
article_number: '044054'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Martin
full_name: Zemlicka, Martin
id: 2DCF8DE6-F248-11E8-B48F-1D18A9856A87
last_name: Zemlicka
orcid: 0009-0005-0878-3032
- first_name: Elena
full_name: Redchenko, Elena
id: 2C21D6E8-F248-11E8-B48F-1D18A9856A87
last_name: Redchenko
- first_name: Matilda
full_name: Peruzzo, Matilda
id: 3F920B30-F248-11E8-B48F-1D18A9856A87
last_name: Peruzzo
orcid: 0000-0002-3415-4628
- first_name: Farid
full_name: Hassani, Farid
id: 2AED110C-F248-11E8-B48F-1D18A9856A87
last_name: Hassani
orcid: 0000-0001-6937-5773
- first_name: Andrea
full_name: Trioni, Andrea
id: 42F71B44-F248-11E8-B48F-1D18A9856A87
last_name: Trioni
- first_name: Shabir
full_name: Barzanjeh, Shabir
id: 2D25E1F6-F248-11E8-B48F-1D18A9856A87
last_name: Barzanjeh
orcid: 0000-0003-0415-1423
- first_name: Johannes M
full_name: Fink, Johannes M
id: 4B591CBA-F248-11E8-B48F-1D18A9856A87
last_name: Fink
orcid: 0000-0001-8112-028X
citation:
ama: 'Zemlicka M, Redchenko E, Peruzzo M, et al. Compact vacuum-gap transmon qubits:
Selective and sensitive probes for superconductor surface losses. Physical
Review Applied. 2023;20(4). doi:10.1103/PhysRevApplied.20.044054'
apa: 'Zemlicka, M., Redchenko, E., Peruzzo, M., Hassani, F., Trioni, A., Barzanjeh,
S., & Fink, J. M. (2023). Compact vacuum-gap transmon qubits: Selective and
sensitive probes for superconductor surface losses. Physical Review Applied.
American Physical Society. https://doi.org/10.1103/PhysRevApplied.20.044054'
chicago: 'Zemlicka, Martin, Elena Redchenko, Matilda Peruzzo, Farid Hassani, Andrea
Trioni, Shabir Barzanjeh, and Johannes M Fink. “Compact Vacuum-Gap Transmon Qubits:
Selective and Sensitive Probes for Superconductor Surface Losses.” Physical
Review Applied. American Physical Society, 2023. https://doi.org/10.1103/PhysRevApplied.20.044054.'
ieee: 'M. Zemlicka et al., “Compact vacuum-gap transmon qubits: Selective
and sensitive probes for superconductor surface losses,” Physical Review Applied,
vol. 20, no. 4. American Physical Society, 2023.'
ista: 'Zemlicka M, Redchenko E, Peruzzo M, Hassani F, Trioni A, Barzanjeh S, Fink
JM. 2023. Compact vacuum-gap transmon qubits: Selective and sensitive probes for
superconductor surface losses. Physical Review Applied. 20(4), 044054.'
mla: 'Zemlicka, Martin, et al. “Compact Vacuum-Gap Transmon Qubits: Selective and
Sensitive Probes for Superconductor Surface Losses.” Physical Review Applied,
vol. 20, no. 4, 044054, American Physical Society, 2023, doi:10.1103/PhysRevApplied.20.044054.'
short: M. Zemlicka, E. Redchenko, M. Peruzzo, F. Hassani, A. Trioni, S. Barzanjeh,
J.M. Fink, Physical Review Applied 20 (2023).
corr_author: '1'
date_created: 2023-11-12T23:00:55Z
date_published: 2023-10-20T00:00:00Z
date_updated: 2026-04-15T06:39:01Z
day: '20'
department:
- _id: JoFi
doi: 10.1103/PhysRevApplied.20.044054
ec_funded: 1
external_id:
arxiv:
- '2206.14104'
isi:
- '001095315600001'
intvolume: ' 20'
isi: 1
issue: '4'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/2206.14104
month: '10'
oa: 1
oa_version: Preprint
project:
- _id: 26336814-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '758053'
name: A Fiber Optic Transceiver for Superconducting Qubits
- _id: eb9b30ac-77a9-11ec-83b8-871f581d53d2
name: Protected states of quantum matter
- _id: 258047B6-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '707438'
name: 'Microwave-to-Optical Quantum Link: Quantum Teleportation and Quantum Illumination
with cavity Optomechanics'
- _id: bdb7cfc1-d553-11ed-ba76-d2eaab167738
grant_number: '101080139'
name: Open Superconducting Quantum Computers (OpenSuperQPlus)
- _id: bdb108fd-d553-11ed-ba76-83dc74a9864f
grant_number: F07105
name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration
of Superconducting Quantum Circuits
publication: Physical Review Applied
publication_identifier:
eissn:
- 2331-7019
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
related_material:
record:
- id: '14520'
relation: research_data
status: public
scopus_import: '1'
status: public
title: 'Compact vacuum-gap transmon qubits: Selective and sensitive probes for superconductor
surface losses'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 20
year: '2023'
...