---
OA_place: publisher
OA_type: hybrid
PlanS_conform: '1'
_id: '21449'
abstract:
- lang: eng
  text: Three-dimensional (3D) crystals offer a route to scaling up trapped-ion systems
    for quantum sensing and quantum simulation applications; however, engineering
    coherent spin-motion couplings and effective spin-spin interactions in large crystals
    poses technical challenges associated with decoherence and prolonged timescales
    to generate appreciable entanglement. Here, we explore the possibility of speeding
    up these interactions in 3D crystals via parametric amplification. For this purpose,
    we derive a general Hamiltonian for the parametric amplification of spin-motion
    coupling that is broadly applicable to normal modes with motion transverse to
    or along the spatial extent of the crystal. Unlike in lower-dimensional crystals,
    we find that the ability to faithfully (uniformly) amplify the spin-spin interactions
    in 3D crystals depends on the physical implementation of the spin-motion coupling.
    We consider the light-shift gate, and the so-called phase-insensitive and phase-sensitive
    Mølmer-Sørensen (MS) gates, and we find that only the phase-sensitive MS gate
    can be faithfully amplified in general 3D crystals. We discuss a situation where
    nonuniform amplification can be advantageous. We also reconsider the effect of
    counter-rotating terms on parametric amplification and find that they are not
    as detrimental as previous studies suggest.
acknowledgement: We thank Wenchao Ge and Allison Carter for feedback on the manuscript.
  We also thank Wenchao Ge for sharing the numerical simulation data that we have
  used in Fig. 5 of this paper. N.N. would like to thank Perimeter Institute and Boston
  University for support during this research. S.H. acknowledges partial support from
  the Institute of Science and Technology Austria and the Austrian Science Fund (FWF)
  DOI 10.55776/F71 for the duration of this project. This work was supported by DOE
  Quantum Systems Accelerator, ARO W911NF24-1-0128, and NSF JILA-PFC PHY-2317149.
  J.J.B. and A.M.R. acknowledge support through AFOSR Grant No. FA9550-25-1-0080.
  A.S. acknowledges support by the Department of Science and Technology, Govt. of
  India through the INSPIRE Faculty Award (DST/INSPIRE/04/2023/001486), by the Anusandhan
  National Research Foundation (ANRF), Govt. of India through the Prime Minister’s
  Early Career Research Grant (PMECRG) (ANRF/ECRG/2024/001160/PMS) and by IIT Madras
  through the New Faculty Initiation Grant (NFIG).
article_number: '034004'
article_processing_charge: Yes (via OA deal)
article_type: original
arxiv: 1
author:
- first_name: Samarth
  full_name: Hawaldar, Samarth
  id: 221708e1-1ff6-11ee-9fa6-85146607433e
  last_name: Hawaldar
  orcid: 0000-0002-1965-4309
- first_name: N.
  full_name: Nikhil, N.
  last_name: Nikhil
- first_name: Ana Maria
  full_name: Rey, Ana Maria
  last_name: Rey
- first_name: John J.
  full_name: Bollinger, John J.
  last_name: Bollinger
- first_name: Athreya
  full_name: Shankar, Athreya
  last_name: Shankar
citation:
  ama: Hawaldar S, Nikhil N, Rey AM, Bollinger JJ, Shankar A. Parametric amplification
    of spin-motion coupling in three-dimensional trapped-ion crystals. <i>Physical
    Review Applied</i>. 2026;25(3). doi:<a href="https://doi.org/10.1103/h1m9-h3yw">10.1103/h1m9-h3yw</a>
  apa: Hawaldar, S., Nikhil, N., Rey, A. M., Bollinger, J. J., &#38; Shankar, A. (2026).
    Parametric amplification of spin-motion coupling in three-dimensional trapped-ion
    crystals. <i>Physical Review Applied</i>. American Physical Society. <a href="https://doi.org/10.1103/h1m9-h3yw">https://doi.org/10.1103/h1m9-h3yw</a>
  chicago: Hawaldar, Samarth, N. Nikhil, Ana Maria Rey, John J. Bollinger, and Athreya
    Shankar. “Parametric Amplification of Spin-Motion Coupling in Three-Dimensional
    Trapped-Ion Crystals.” <i>Physical Review Applied</i>. American Physical Society,
    2026. <a href="https://doi.org/10.1103/h1m9-h3yw">https://doi.org/10.1103/h1m9-h3yw</a>.
  ieee: S. Hawaldar, N. Nikhil, A. M. Rey, J. J. Bollinger, and A. Shankar, “Parametric
    amplification of spin-motion coupling in three-dimensional trapped-ion crystals,”
    <i>Physical Review Applied</i>, vol. 25, no. 3. American Physical Society, 2026.
  ista: Hawaldar S, Nikhil N, Rey AM, Bollinger JJ, Shankar A. 2026. Parametric amplification
    of spin-motion coupling in three-dimensional trapped-ion crystals. Physical Review
    Applied. 25(3), 034004.
  mla: Hawaldar, Samarth, et al. “Parametric Amplification of Spin-Motion Coupling
    in Three-Dimensional Trapped-Ion Crystals.” <i>Physical Review Applied</i>, vol.
    25, no. 3, 034004, American Physical Society, 2026, doi:<a href="https://doi.org/10.1103/h1m9-h3yw">10.1103/h1m9-h3yw</a>.
  short: S. Hawaldar, N. Nikhil, A.M. Rey, J.J. Bollinger, A. Shankar, Physical Review
    Applied 25 (2026).
corr_author: '1'
date_created: 2026-03-15T23:01:35Z
date_published: 2026-03-01T00:00:00Z
date_updated: 2026-04-14T09:04:08Z
day: '01'
ddc:
- '530'
department:
- _id: JoFi
- _id: GradSch
doi: 10.1103/h1m9-h3yw
external_id:
  arxiv:
  - '2507.16741'
file:
- access_level: open_access
  checksum: f0dc6a50222b778fd75cc72a28d38689
  content_type: application/pdf
  creator: dernst
  date_created: 2026-03-16T09:24:53Z
  date_updated: 2026-03-16T09:24:53Z
  file_id: '21456'
  file_name: 2026_PhysicalReviewApplied_Hawaldar.pdf
  file_size: 1421954
  relation: main_file
  success: 1
file_date_updated: 2026-03-16T09:24:53Z
fulldoi: https://doi.org/10.1103/h1m9-h3yw
has_accepted_license: '1'
intvolume: '        25'
issue: '3'
language:
- iso: eng
month: '03'
oa: 1
oa_version: Published Version
project:
- _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'
scopus_import: '1'
status: public
title: Parametric amplification of spin-motion coupling in three-dimensional trapped-ion
  crystals
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 25
year: '2026'
...
---
OA_place: repository
OA_type: green
_id: '21870'
abstract:
- lang: eng
  text: Superconducting qubits are a leading candidate for utility-scale quantum computing
    due to their fast gate speeds and steadily decreasing error rates. The requirement
    for millikelvin operating temperatures, however, creates a significant scaling
    bottleneck. Modular architectures using optical fiber links could bridge separate
    cryogenic nodes, but superconducting circuits do not have coherent optical transitions
    and microwave-to-optical conversion has not been shown for any non-classical photon
    state. In this work, we demonstrate the on-demand generation and tomographic reconstruction
    of itinerant single microwave photons at 8.9 GHz from a superconducting qubit.
    We upconvert this non-Gaussian state with a transducer added noise below 0.012
    quanta and count the converted telecom photons at 193.4 THz with a signal-to-noise
    ratio of up to 5.1$\pm$1.1. We characterize the trade-offs between throughput
    and noise, and establish a viable path toward heralded entanglement distribution
    and gate teleportation. Looking ahead, these results empower existing superconducting
    devices to take a key role in distributed quantum technologies and heterogeneous
    quantum systems.
acknowledgement: "We thank Fritz Diorico and Onur Hosten who suggested the filter
  cavity design, and gave important insights about the assembly and the testing of
  the FabryPerot filter cavities. Ekatrina Fedotova and Diego A.\r\nLancheros Naranjo
  worked on the filter cavity setup in\r\nthe early stages of this work. Gustavo Wiederhecker
  and\r\nYiewen Chu provided insights as to the origins of the\r\nobserved optical
  noise and Nicola Carlon Zambon suggested using telecom filters to mitigate it further.
  This\r\nwork was supported by the European Research Council under grant agreement
  no. 101089099 (ERC CoG\r\ncQEO), and 101248662 (ERC POC CoupledEOT), the\r\nEuropean
  Unions Horizon 2020 research and innovation\r\nprogram under grant agreement no.
  899354 (FETopen\r\nSuperQuLAN), the European Innovation Council no.\r\n101187231
  (PathfinderOpen CIELO), and the Austrian\r\nScience Fund (FWF) no. F7105 (SFB BeyondC).
  J.F.\r\nand L.K. acknowledge support from the Horizon Europe\r\nProgram HORIZON-CL4-2022-QUANTUM-01-SGA
  via\r\nProject No. 101113946 OpenSuperQPlus100. A.M. acknowledges support from the
  NOMIS-ISTA fellowship."
article_processing_charge: No
arxiv: 1
author:
- first_name: Thomas
  full_name: Werner, Thomas
  id: 1fcd8497-dba3-11ea-a45e-c6fbd715f7c7
  last_name: Werner
  orcid: 0009-0001-2346-5236
- first_name: Erfan
  full_name: Riyazi, Erfan
  id: 53322f94-5355-11ee-ae5a-ff6f81c87d51
  last_name: Riyazi
- first_name: Samarth
  full_name: Hawaldar, Samarth
  id: 221708e1-1ff6-11ee-9fa6-85146607433e
  last_name: Hawaldar
  orcid: 0000-0002-1965-4309
- first_name: Rishabh
  full_name: Sahu, Rishabh
  id: 47D26E34-F248-11E8-B48F-1D18A9856A87
  last_name: Sahu
  orcid: 0000-0001-6264-2162
- first_name: Georg M
  full_name: Arnold, Georg M
  id: 3770C838-F248-11E8-B48F-1D18A9856A87
  last_name: Arnold
  orcid: 0000-0003-1397-7876
- first_name: Paul Falthansl-Scheinecker
  full_name: Paul Falthansl-Scheinecker, Paul Falthansl-Scheinecker
  last_name: Paul Falthansl-Scheinecker
- first_name: Jennifer A. Sánchez
  full_name: Naranjo, Jennifer A. Sánchez
  last_name: Naranjo
- first_name: Dante
  full_name: Loi, Dante
  last_name: Loi
- first_name: Lucky N.
  full_name: Kapoor, Lucky N.
  last_name: Kapoor
- first_name: Martin
  full_name: Zemlicka, Martin
  id: 2DCF8DE6-F248-11E8-B48F-1D18A9856A87
  last_name: Zemlicka
  orcid: 0009-0005-0878-3032
- first_name: Liu
  full_name: Qiu, Liu
  id: 45e99c0d-1eb1-11eb-9b96-ed8ab2983cac
  last_name: Qiu
  orcid: 0000-0003-4345-4267
- first_name: Andrei
  full_name: Militaru, Andrei
  id: d67706f8-8eb1-11ee-ad1b-9c30dfa19e0b
  last_name: Militaru
- 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: Werner T, Riyazi E, Hawaldar S, et al. Electro-optic conversion of itinerant
    Fock states. <i>arXiv</i>. doi:<a href="https://doi.org/10.48550/arXiv.2602.00928">10.48550/arXiv.2602.00928</a>
  apa: Werner, T., Riyazi, E., Hawaldar, S., Sahu, R., Arnold, G. M., Paul Falthansl-Scheinecker,
    P. F.-S., … Fink, J. M. (n.d.). Electro-optic conversion of itinerant Fock states.
    <i>arXiv</i>. <a href="https://doi.org/10.48550/arXiv.2602.00928">https://doi.org/10.48550/arXiv.2602.00928</a>
  chicago: Werner, Thomas, Erfan Riyazi, Samarth Hawaldar, Rishabh Sahu, Georg M Arnold,
    Paul Falthansl-Scheinecker Paul Falthansl-Scheinecker, Jennifer A. Sánchez Naranjo,
    et al. “Electro-Optic Conversion of Itinerant Fock States.” <i>ArXiv</i>, n.d.
    <a href="https://doi.org/10.48550/arXiv.2602.00928">https://doi.org/10.48550/arXiv.2602.00928</a>.
  ieee: T. Werner <i>et al.</i>, “Electro-optic conversion of itinerant Fock states,”
    <i>arXiv</i>. .
  ista: Werner T, Riyazi E, Hawaldar S, Sahu R, Arnold GM, Paul Falthansl-Scheinecker
    PF-S, Naranjo JAS, Loi D, Kapoor LN, Zemlicka M, Qiu L, Militaru A, Fink JM. Electro-optic
    conversion of itinerant Fock states. arXiv, <a href="https://doi.org/10.48550/arXiv.2602.00928">10.48550/arXiv.2602.00928</a>.
  mla: Werner, Thomas, et al. “Electro-Optic Conversion of Itinerant Fock States.”
    <i>ArXiv</i>, doi:<a href="https://doi.org/10.48550/arXiv.2602.00928">10.48550/arXiv.2602.00928</a>.
  short: T. Werner, E. Riyazi, S. Hawaldar, R. Sahu, G.M. Arnold, P.F.-S. Paul Falthansl-Scheinecker,
    J.A.S. Naranjo, D. Loi, L.N. Kapoor, M. Zemlicka, L. Qiu, A. Militaru, J.M. Fink,
    ArXiv (n.d.).
corr_author: '1'
date_created: 2026-05-12T13:58:18Z
date_published: 2026-01-31T00:00:00Z
date_updated: 2026-09-14T07:08:55Z
day: '31'
department:
- _id: JoFi
- _id: GradSch
doi: 10.48550/arXiv.2602.00928
ec_funded: 1
external_id:
  arxiv:
  - '2602.00928'
fulldoi: https://doi.org/10.48550/arXiv.2602.00928
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.2602.00928
month: '01'
oa: 1
oa_version: Preprint
project:
- _id: bdadfa0d-d553-11ed-ba76-fb85edbd456a
  grant_number: '101089099'
  name: 'Cavity Quantum Electro Optics: Microwave photonics with nonclassical states'
- _id: 5b807754-ab3d-11f0-914f-ff8c34502cc9
  grant_number: '101248662'
  name: Integrated optical coupling for low loss electro-optic interconnects
- _id: 9B868D20-BA93-11EA-9121-9846C619BF3A
  call_identifier: H2020
  grant_number: '899354'
  name: Quantum Local Area Networks with Superconducting Qubits
- _id: 91aaf765-16d5-11f0-9cad-a8e7e44cccb7
  grant_number: '101187231'
  name: 'Cavity-Integrated Electro-Optics: Measuring, Converting and Manipulating
    Microwaves with Light'
- _id: 9B861AAC-BA93-11EA-9121-9846C619BF3A
  name: NOMIS Fellowship Program
- _id: bdb108fd-d553-11ed-ba76-83dc74a9864f
  grant_number: F07105
  name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration
    of Superconducting Quantum Circuits
publication: arXiv
publication_status: draft
related_material:
  record:
  - id: '21863'
    relation: dissertation_contains
    status: public
scopus_import: '1'
status: public
title: Electro-optic conversion of itinerant Fock states
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: preprint
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '22637'
abstract:
- lang: eng
  text: The distribution of entanglement across distant qubits is a central challenge
    for the operation of scalable quantum computers and large-scale quantum networks.
    Existing approaches rely on deterministic state transfer, or probabilistic protocols
    that require active control or measurements and postselection. Here, we demonstrate
    a fundamentally different, fully autonomous process, where two remote qubits are
    entangled through their coupling to a quantum-correlated photonic reservoir. In
    our experiment, a Josephson parametric converter produces a Gaussian, continuous-variable
    entangled state of propagating microwave fields that drives two spatially separated
    superconducting transmon qubits into a stationary, discrete-variable entangled
    state. We also show how qubit tomography unlocks a direct and sensitive verification
    of two-mode squeezing in the microwave domain. These results establish networks
    of qubits interfaced with distributed continuous-variable entangled states as
    a powerful platform for foundational studies and quantum-technology applications.
acknowledged_ssus:
- _id: M-Shop
- _id: NanoFab
acknowledgement: We thank A. Trioni and C. N. Borja for assistance in device fabrication,
  C. Siegele for fruitful discussions, IBM for donating the JPC used in this work,
  and the MIBA machine shop and the ISTA nanofabrication facility for technical support.
  This work was funded in part by the Austrian Science Fund (FWF) through the excellence
  cluster quantA 10.55776/COE1 and the SFB BeyondC 10.55776/F71, as well as the European
  Union—NextGenerationEU, and ISTA. J. F. and L. K. acknowledge support from the Horizon
  Europe Program HORIZON-CL4-2022-QUANTUM-01-SGA via Project No. 101113946 OpenSuperQPlus100,
  and J. F. from the European Research Council No. 101089099 (ERC CoG cQEO). J. A.
  acknowledges support from the QUANTERA project MOLAR with reference No. PCI2024-153449,
  funded by MICIU/AEI/10.13039/501100011033 and the European Union. This research
  is part of the Munich Quantum Valley, which is supported by the Bavarian state government
  with funds from the Hightech Agenda Bayern Plus.
article_number: '031005'
article_processing_charge: Yes
article_type: original
author:
- first_name: Alejandro
  full_name: Andres Juanes, Alejandro
  id: 7601fd3a-5355-11ee-ae5a-a20ca6f3cfb9
  last_name: Andres Juanes
- first_name: J.
  full_name: Agustí, J.
  last_name: Agustí
- first_name: Riya
  full_name: Sett, Riya
  id: 2E6D040E-F248-11E8-B48F-1D18A9856A87
  last_name: Sett
  orcid: 0000-0001-7641-8348
- first_name: Elena
  full_name: Redchenko, Elena
  id: 2C21D6E8-F248-11E8-B48F-1D18A9856A87
  last_name: Redchenko
- first_name: Lucky
  full_name: Kapoor, Lucky
  id: 84b9700b-15b2-11ec-abd3-831089e67615
  last_name: Kapoor
  orcid: 0000-0001-8319-2148
- first_name: Samarth
  full_name: Hawaldar, Samarth
  id: 221708e1-1ff6-11ee-9fa6-85146607433e
  last_name: Hawaldar
  orcid: 0000-0002-1965-4309
- first_name: P.
  full_name: Rabl, P.
  last_name: Rabl
- 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: Andres Juanes A, Agustí J, Sett R, et al. Distributing stationary qubit entanglement
    through a nonlocal squeezed reservoir. <i>Physical Review X</i>. 2026;16(3). doi:<a
    href="https://doi.org/10.1103/r4jt-j39w">10.1103/r4jt-j39w</a>
  apa: Andres Juanes, A., Agustí, J., Sett, R., Redchenko, E., Kapoor, L., Hawaldar,
    S., … Fink, J. M. (2026). Distributing stationary qubit entanglement through a
    nonlocal squeezed reservoir. <i>Physical Review X</i>. American Physical Society.
    <a href="https://doi.org/10.1103/r4jt-j39w">https://doi.org/10.1103/r4jt-j39w</a>
  chicago: Andres Juanes, Alejandro, J. Agustí, Riya Sett, Elena Redchenko, Lucky
    Kapoor, Samarth Hawaldar, P. Rabl, and Johannes M Fink. “Distributing Stationary
    Qubit Entanglement through a Nonlocal Squeezed Reservoir.” <i>Physical Review
    X</i>. American Physical Society, 2026. <a href="https://doi.org/10.1103/r4jt-j39w">https://doi.org/10.1103/r4jt-j39w</a>.
  ieee: A. Andres Juanes <i>et al.</i>, “Distributing stationary qubit entanglement
    through a nonlocal squeezed reservoir,” <i>Physical Review X</i>, vol. 16, no.
    3. American Physical Society, 2026.
  ista: Andres Juanes A, Agustí J, Sett R, Redchenko E, Kapoor L, Hawaldar S, Rabl
    P, Fink JM. 2026. Distributing stationary qubit entanglement through a nonlocal
    squeezed reservoir. Physical Review X. 16(3), 031005.
  mla: Andres Juanes, Alejandro, et al. “Distributing Stationary Qubit Entanglement
    through a Nonlocal Squeezed Reservoir.” <i>Physical Review X</i>, vol. 16, no.
    3, 031005, American Physical Society, 2026, doi:<a href="https://doi.org/10.1103/r4jt-j39w">10.1103/r4jt-j39w</a>.
  short: A. Andres Juanes, J. Agustí, R. Sett, E. Redchenko, L. Kapoor, S. Hawaldar,
    P. Rabl, J.M. Fink, Physical Review X 16 (2026).
corr_author: '1'
das_tickbox: '1'
dataavailabilitystatement: The data that support the findings of this article are
  openly available  https://zenodo.org/records/19099731.
date_created: 2026-08-03T13:19:31Z
date_published: 2026-07-13T00:00:00Z
date_updated: 2026-09-16T07:38:20Z
day: '13'
ddc:
- '530'
department:
- _id: JoFi
- _id: GradSch
doi: 10.1103/r4jt-j39w
file:
- access_level: open_access
  checksum: 2bab109f975545d096c21dd72c738b6e
  content_type: application/pdf
  creator: dernst
  date_created: 2026-08-04T05:40:41Z
  date_updated: 2026-08-04T05:40:41Z
  file_id: '22640'
  file_name: 2026_PhysicalReviewX_AndresJuanes.pdf
  file_size: 5301241
  relation: main_file
  success: 1
file_date_updated: 2026-08-04T05:40:41Z
fulldoi: https://doi.org/10.1103/r4jt-j39w
has_accepted_license: '1'
intvolume: '        16'
issue: '3'
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
project:
- _id: bdb108fd-d553-11ed-ba76-83dc74a9864f
  grant_number: F07105
  name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration
    of Superconducting Quantum Circuits
- _id: bdadfa0d-d553-11ed-ba76-fb85edbd456a
  grant_number: '101089099'
  name: 'Cavity Quantum Electro Optics: Microwave photonics with nonclassical states'
- _id: 92af0f81-16d5-11f0-9cad-924b22d6a876
  grant_number: COE01
  name: Quantum Science Austria (Fink)
publication: Physical Review X
publication_identifier:
  eissn:
  - 2160-3308
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
related_material:
  link:
  - description: News on ISTA website
    relation: press_release
    url: https://ista.ac.at/en/news/quantum-bath-syncs-distant-qubits/
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: yes
title: Distributing stationary qubit entanglement through a nonlocal squeezed reservoir
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 16
year: '2026'
...
---
OA_place: repository
OA_type: green
_id: '20976'
abstract:
- lang: eng
  text: We present an experimental demonstration of an impedance-engineered Josephson
    parametric amplifier (IEJPA) fabricated in a single-step lithography process.
    Impedance-engineering is implemented using a lumped-element series LC circuit.
    We use a simpler lithography process where the entire device—impedance transformer
    and Josephson parametric amplifier (JPA)—is patterned in a single electron beam
    lithography step, followed by a double-angle Dolan-bridge technique for Al–AlOx–Al
    deposition. We observe amplification with 18 dB gain over a wide 400 MHz bandwidth
    centered around 5.3 GHz with added noise approaching the quantum limit, and a
    saturation power of −114 dBm. To accurately explain our experimental results,
    we extend existing theories for IEJPAs to incorporate the full sine nonlinearity
    of both the JPA and the transformer. Our work provides a route to simpler realization
    of broadband JPAs and a theoretical foundation for a regime of JPA operation that
    has been less explored in literature.
acknowledgement: The authors acknowledge receiving support from the Space Technology
  Cell at IISc and ISRO through the project STC-0444(2022) and the Ministry of Electronics
  and Information Technology of the Government of India, under the centre of Excellence
  of Quantum Technology at the Indian Institute of Science, as well as the office
  of Principle Scientific Advisor, Government of India. S.H. and A.P. acknowledge
  the support of the Kishore Vaigyanik Protsahan Yojana (KVPY). A.S. acknowledges
  the support of a New Faculty Initiation Grant (NFIG) from IIT Madras.
article_number: '254001'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Lipi
  full_name: Patel, Lipi
  last_name: Patel
- first_name: Samarth
  full_name: Hawaldar, Samarth
  id: 221708e1-1ff6-11ee-9fa6-85146607433e
  last_name: Hawaldar
  orcid: 0000-0002-1965-4309
- first_name: Aditya
  full_name: Panikkar, Aditya
  last_name: Panikkar
- first_name: Athreya
  full_name: Shankar, Athreya
  last_name: Shankar
- first_name: Baladitya
  full_name: Suri, Baladitya
  last_name: Suri
citation:
  ama: Patel L, Hawaldar S, Panikkar A, Shankar A, Suri B. Impedance-engineered Josephson
    parametric amplifier with single-step lithography. <i>Applied Physics Letters</i>.
    2025;127(25). doi:<a href="https://doi.org/10.1063/5.0290636">10.1063/5.0290636</a>
  apa: Patel, L., Hawaldar, S., Panikkar, A., Shankar, A., &#38; Suri, B. (2025).
    Impedance-engineered Josephson parametric amplifier with single-step lithography.
    <i>Applied Physics Letters</i>. AIP Publishing. <a href="https://doi.org/10.1063/5.0290636">https://doi.org/10.1063/5.0290636</a>
  chicago: Patel, Lipi, Samarth Hawaldar, Aditya Panikkar, Athreya Shankar, and Baladitya
    Suri. “Impedance-Engineered Josephson Parametric Amplifier with Single-Step Lithography.”
    <i>Applied Physics Letters</i>. AIP Publishing, 2025. <a href="https://doi.org/10.1063/5.0290636">https://doi.org/10.1063/5.0290636</a>.
  ieee: L. Patel, S. Hawaldar, A. Panikkar, A. Shankar, and B. Suri, “Impedance-engineered
    Josephson parametric amplifier with single-step lithography,” <i>Applied Physics
    Letters</i>, vol. 127, no. 25. AIP Publishing, 2025.
  ista: Patel L, Hawaldar S, Panikkar A, Shankar A, Suri B. 2025. Impedance-engineered
    Josephson parametric amplifier with single-step lithography. Applied Physics Letters.
    127(25), 254001.
  mla: Patel, Lipi, et al. “Impedance-Engineered Josephson Parametric Amplifier with
    Single-Step Lithography.” <i>Applied Physics Letters</i>, vol. 127, no. 25, 254001,
    AIP Publishing, 2025, doi:<a href="https://doi.org/10.1063/5.0290636">10.1063/5.0290636</a>.
  short: L. Patel, S. Hawaldar, A. Panikkar, A. Shankar, B. Suri, Applied Physics
    Letters 127 (2025).
date_created: 2026-01-11T23:01:34Z
date_published: 2025-12-22T00:00:00Z
date_updated: 2026-01-12T09:57:53Z
day: '22'
department:
- _id: JoFi
doi: 10.1063/5.0290636
external_id:
  arxiv:
  - '2507.09298'
fulldoi: https://doi.org/10.1063/5.0290636
intvolume: '       127'
issue: '25'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.2507.09298
month: '12'
oa: 1
oa_version: Preprint
publication: Applied Physics Letters
publication_identifier:
  eissn:
  - 1077-3118
  issn:
  - 0003-6951
publication_status: published
publisher: AIP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: Impedance-engineered Josephson parametric amplifier with single-step lithography
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 127
year: '2025'
...
---
OA_place: publisher
OA_type: hybrid
_id: '19617'
abstract:
- lang: eng
  text: In this article, we propose a method for generating single microwave photons
    in superconducting circuits. We theoretically show that pure single microwave
    photons can be generated on demand and tuned over a large frequency band by making
    use of Landau-Zener transitions under a rapid sweep of a control parameter. We
    devise a protocol that enables fast control of the frequency of the emitted photon
    over two octaves, without requiring extensive calibration. Additionally, we make
    theoretical estimates of the generation efficiency, tunability, purity, and linewidth
    of the photons emitted using this method for both charge- and flux-qubit-based
    architectures. We also provide estimates of the optimal device parameters required
    for these architectures to realize the device.
acknowledgement: The authors acknowledge the support of DST-INSPIRE Fellowship No.
  IF180339 and DST-SERB Core Research Grant No. CRG/2018/002129. S.H. acknowledges
  the support of the Kishore Vaigyanik Protsahan Yojana (KVPY). S.H. also acknowledges
  helpful discussions with Harsh Arora and Johannes Fink.
article_number: '044042'
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Samarth
  full_name: Hawaldar, Samarth
  id: 221708e1-1ff6-11ee-9fa6-85146607433e
  last_name: Hawaldar
  orcid: 0000-0002-1965-4309
- first_name: Siddhi Satish
  full_name: Khaire, Siddhi Satish
  last_name: Khaire
- first_name: Per
  full_name: Delsing, Per
  last_name: Delsing
- first_name: Baladitya
  full_name: Suri, Baladitya
  last_name: Suri
citation:
  ama: Hawaldar S, Khaire SS, Delsing P, Suri B. On-demand single-microwave-photon
    source in a superconducting circuit with wideband frequency tunability. <i>Physical
    Review Applied</i>. 2025;23(4). doi:<a href="https://doi.org/10.1103/physrevapplied.23.044042">10.1103/physrevapplied.23.044042</a>
  apa: Hawaldar, S., Khaire, S. S., Delsing, P., &#38; Suri, B. (2025). On-demand
    single-microwave-photon source in a superconducting circuit with wideband frequency
    tunability. <i>Physical Review Applied</i>. American Physical Society. <a href="https://doi.org/10.1103/physrevapplied.23.044042">https://doi.org/10.1103/physrevapplied.23.044042</a>
  chicago: Hawaldar, Samarth, Siddhi Satish Khaire, Per Delsing, and Baladitya Suri.
    “On-Demand Single-Microwave-Photon Source in a Superconducting Circuit with Wideband
    Frequency Tunability.” <i>Physical Review Applied</i>. American Physical Society,
    2025. <a href="https://doi.org/10.1103/physrevapplied.23.044042">https://doi.org/10.1103/physrevapplied.23.044042</a>.
  ieee: S. Hawaldar, S. S. Khaire, P. Delsing, and B. Suri, “On-demand single-microwave-photon
    source in a superconducting circuit with wideband frequency tunability,” <i>Physical
    Review Applied</i>, vol. 23, no. 4. American Physical Society, 2025.
  ista: Hawaldar S, Khaire SS, Delsing P, Suri B. 2025. On-demand single-microwave-photon
    source in a superconducting circuit with wideband frequency tunability. Physical
    Review Applied. 23(4), 044042.
  mla: Hawaldar, Samarth, et al. “On-Demand Single-Microwave-Photon Source in a Superconducting
    Circuit with Wideband Frequency Tunability.” <i>Physical Review Applied</i>, vol.
    23, no. 4, 044042, American Physical Society, 2025, doi:<a href="https://doi.org/10.1103/physrevapplied.23.044042">10.1103/physrevapplied.23.044042</a>.
  short: S. Hawaldar, S.S. Khaire, P. Delsing, B. Suri, Physical Review Applied 23
    (2025).
corr_author: '1'
date_created: 2025-04-24T06:34:07Z
date_published: 2025-04-18T00:00:00Z
date_updated: 2025-09-30T12:17:33Z
day: '18'
ddc:
- '539'
department:
- _id: GradSch
- _id: JoFi
doi: 10.1103/physrevapplied.23.044042
external_id:
  isi:
  - '001490745300002'
file:
- access_level: open_access
  checksum: 582b2ed6afb654300cabf0e3add14ca8
  content_type: application/pdf
  creator: shawalda
  date_created: 2025-04-24T06:40:22Z
  date_updated: 2025-04-24T06:40:22Z
  file_id: '19620'
  file_name: PhysRevApplied.23.044042.pdf
  file_size: 837219
  relation: main_file
  success: 1
file_date_updated: 2025-04-24T06:40:22Z
fulldoi: https://doi.org/10.1103/physrevapplied.23.044042
has_accepted_license: '1'
intvolume: '        23'
isi: 1
issue: '4'
language:
- iso: eng
month: '04'
oa: 1
oa_version: Published Version
publication: Physical Review Applied
publication_identifier:
  issn:
  - 2331-7019
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: On-demand single-microwave-photon source in a superconducting circuit with
  wideband frequency tunability
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 23
year: '2025'
...
---
DOAJ_listed: '1'
_id: '17477'
abstract:
- lang: eng
  text: Trapped-ion systems are a leading platform for quantum information processing,
    but they are currently limited to 1D and 2D arrays, which imposes restrictions
    on both their scalability and their range of applications. Here, we propose a
    path to overcome this limitation by demonstrating that Penning traps can be used
    to realize remarkably clean bilayer crystals, wherein hundreds of ions self-organize
    into two well-defined layers. These bilayer crystals are made possible by the
    inclusion of an anharmonic trapping potential, which is readily implementable
    with current technology. We study the normal modes of this system and discover
    salient differences compared to the modes of single-plane crystals. The bilayer
    geometry and the unique properties of the normal modes open new opportunities—in
    particular, in quantum sensing and quantum simulation—that are not straightforward
    in single-plane crystals. Furthermore, we illustrate that it may be possible to
    extend the ideas presented here to realize multilayer crystals with more than
    two layers. Our work increases the dimensionality of trapped-ion systems by efficiently
    utilizing all three spatial dimensions, and it lays the foundation for a new generation
    of quantum information processing experiments with multilayer 3D crystals of trapped
    ions.
acknowledgement: We thank M. Miskeen Khan, Jennifer Lilieholm, and Wes Johnson for
  a careful reading and feedback on the manuscript. We acknowledge discussions with
  Dan Dubin, John Zaris, and Scott Parker. S. H. acknowledges the support of Kishore
  Vaigyanik Protsahan Yojana, Department of Science and Technology, Government of
  India. A. S. acknowledges the support of a C. V. Raman post-doctoral fellowship.
  A. L. C., A. M. R., and J. J. B. acknowledge funding from the U.S. Department of
  Energy, Office of Science, NQI Science Research Centers, Quantum Systems Accelerator
  (QSA), a collaboration between the U.S. Department of Energy, Office of Science
  and other agencies. A. M. R. acknowledges additional support from VBFF, ARO Grant
  No. W911NF-24-1-0128, by the NSF Grants No. JILA-PFC PHY-2317149 and No. QLCI-OMA-2016244,
  and by NIST. J. J. B. acknowledges additional support from the DARPA ONISQ program
  and AFOSR Grant No. FA9550-201-0019.
article_number: '031030'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Samarth
  full_name: Hawaldar, Samarth
  id: 221708e1-1ff6-11ee-9fa6-85146607433e
  last_name: Hawaldar
  orcid: 0000-0002-1965-4309
- first_name: Prakriti
  full_name: Shahi, Prakriti
  last_name: Shahi
- first_name: Allison L.
  full_name: Carter, Allison L.
  last_name: Carter
- first_name: Ana Maria
  full_name: Rey, Ana Maria
  last_name: Rey
- first_name: John J.
  full_name: Bollinger, John J.
  last_name: Bollinger
- first_name: Athreya
  full_name: Shankar, Athreya
  last_name: Shankar
citation:
  ama: Hawaldar S, Shahi P, Carter AL, Rey AM, Bollinger JJ, Shankar A. Bilayer crystals
    of trapped ions for quantum information processing. <i>Physical Review X</i>.
    2024;14(3). doi:<a href="https://doi.org/10.1103/PhysRevX.14.031030">10.1103/PhysRevX.14.031030</a>
  apa: Hawaldar, S., Shahi, P., Carter, A. L., Rey, A. M., Bollinger, J. J., &#38;
    Shankar, A. (2024). Bilayer crystals of trapped ions for quantum information processing.
    <i>Physical Review X</i>. American Physical Society. <a href="https://doi.org/10.1103/PhysRevX.14.031030">https://doi.org/10.1103/PhysRevX.14.031030</a>
  chicago: Hawaldar, Samarth, Prakriti Shahi, Allison L. Carter, Ana Maria Rey, John
    J. Bollinger, and Athreya Shankar. “Bilayer Crystals of Trapped Ions for Quantum
    Information Processing.” <i>Physical Review X</i>. American Physical Society,
    2024. <a href="https://doi.org/10.1103/PhysRevX.14.031030">https://doi.org/10.1103/PhysRevX.14.031030</a>.
  ieee: S. Hawaldar, P. Shahi, A. L. Carter, A. M. Rey, J. J. Bollinger, and A. Shankar,
    “Bilayer crystals of trapped ions for quantum information processing,” <i>Physical
    Review X</i>, vol. 14, no. 3. American Physical Society, 2024.
  ista: Hawaldar S, Shahi P, Carter AL, Rey AM, Bollinger JJ, Shankar A. 2024. Bilayer
    crystals of trapped ions for quantum information processing. Physical Review X.
    14(3), 031030.
  mla: Hawaldar, Samarth, et al. “Bilayer Crystals of Trapped Ions for Quantum Information
    Processing.” <i>Physical Review X</i>, vol. 14, no. 3, 031030, American Physical
    Society, 2024, doi:<a href="https://doi.org/10.1103/PhysRevX.14.031030">10.1103/PhysRevX.14.031030</a>.
  short: S. Hawaldar, P. Shahi, A.L. Carter, A.M. Rey, J.J. Bollinger, A. Shankar,
    Physical Review X 14 (2024).
corr_author: '1'
date_created: 2024-09-01T22:01:08Z
date_published: 2024-08-16T00:00:00Z
date_updated: 2025-09-08T09:07:29Z
day: '16'
ddc:
- '530'
department:
- _id: JoFi
doi: 10.1103/PhysRevX.14.031030
external_id:
  arxiv:
  - '2312.10681'
  isi:
  - '001293977800002'
file:
- access_level: open_access
  checksum: 5d39b7dda67fd7b9a960235f6f38e280
  content_type: application/pdf
  creator: cchlebak
  date_created: 2024-09-06T09:43:53Z
  date_updated: 2024-09-06T09:43:53Z
  file_id: '17757'
  file_name: 2024_PhysRevX_Hawaldar.pdf
  file_size: 3909653
  relation: main_file
  success: 1
file_date_updated: 2024-09-06T09:43:53Z
fulldoi: https://doi.org/10.1103/PhysRevX.14.031030
has_accepted_license: '1'
intvolume: '        14'
isi: 1
issue: '3'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Published Version
publication: Physical Review X
publication_identifier:
  eissn:
  - 2160-3308
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Bilayer crystals of trapped ions for quantum information processing
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 14
year: '2024'
...