FEBQI

We are the Floating-Electron-Based Quantum Information (FEBQI) research team at RIKEN Center for Quantum Computing.

Our research focuses on electrons floating above liquid helium and solid neon as platforms for quantum information processing. Suspended in vacuum just above the surface, these electrons exist in a pristine, defect-free environment, enabling long coherence times ideal for quantum computing.

Research Topics

Electrons on liquid helium — Plasmon excitations, quantum simulation, and electron spin qubits
Electrons on solid neon — Long coherence times for both charge and spin states, targeting quantum memory
Cryogenic electronics — Development of cryogenic microwave sources for scalable quantum computation

Upcoming

May 18, 2026 — Workshop: Towards Spin Qubits of Electrons on Solid Neon, RIKEN Wako Campus (hybrid). Free registration.

Openings

We are recruiting postdocs and interns (3+ months). Please contact Erika Kawakami for details.

News

Apr 20, 2026

Welcome back, Xianjing!

Mar 25, 2026

Hochan Chung receives Best Bachelor's Thesis Award

Mar 10, 2026

Happy 80th birthday, Oleksiy!

Selected Publications

arXiv

Strong Coupling Between RF Photons and Plasmons of Electrons on Liquid Helium

Asher Jennings^* , Ivan Grytsenko , Thomas Giovansili , Itay Josef Barabash , Oleksiy Rybalko , Yiran Tian , Jun Wang , Hiroki Ikegami , and Erika Kawakami^*

arXiv:2601.22552 (2026).

arXiv Bib

@article{jennings2025plasmon,
  title = {Strong Coupling Between RF Photons and Plasmons of Electrons on Liquid Helium},
  author = {Jennings, Asher and Grytsenko, Ivan and Giovansili, Thomas and Barabash, Itay Josef and Rybalko, Oleksiy and Tian, Yiran and Wang, Jun and Ikegami, Hiroki and Kawakami, Erika},
  journal = {arXiv},
  number = {arXiv:2601.22552},
  year = {2026},
}

PRAppl

Nb-Ti-N nanowire resonators and prospects for spin-photon coupling with electrons on solid neon

Yiran Tian , Ivan Grytsenko , Asher Jennings , Jun Wang , Hiroki Ikegami , Xianjing Zhou , Shuhei Tamate , Hirotaka Terai , Hiroki Kutsuma , Dafei Jin , Monica Benito , and Erika Kawakami^*

Phys. Rev. Applied 25, 024011 (2026).

DOI arXiv Bib Journal

@article{tian2025neon,
  title = {Nb-Ti-N nanowire resonators and prospects for spin-photon coupling with electrons on solid neon},
  author = {Tian, Yiran and Grytsenko, Ivan and Jennings, Asher and Wang, Jun and Ikegami, Hiroki and Zhou, Xianjing and Tamate, Shuhei and Terai, Hirotaka and Kutsuma, Hiroki and Jin, Dafei and Benito, Monica and Kawakami, Erika},
  journal = {Phys. Rev. Applied},
  volume = {25},
  pages = {024011},
  year = {2026},
  doi = {10.1103/jq9v-n4rn},
  overleaf = {https://www.overleaf.com/read/vhqcrdqczzjc#4a4b63},
  index = {2024 neon SC nanowire},
}

PRL

Probing the Quantum Capacitance of Rydberg Transitions of Surface Electrons on Liquid Helium via Microwave Frequency Modulation

Asher Jennings^* , Ivan Grytsenko , Yiran Tian , Oleksiy Rybalko , Jun Wang , Itay Josef Barabash , and Erika Kawakami^*

Phys. Rev. Lett. 135, 087001 (2025).

Editors’ Suggestion

DOI arXiv Bib Journal

@article{jennings2025rydberg,
  title = {Probing the Quantum Capacitance of Rydberg Transitions of Surface Electrons on Liquid Helium via Microwave Frequency Modulation},
  author = {Jennings, Asher and Grytsenko, Ivan and Tian, Yiran and Rybalko, Oleksiy and Wang, Jun and Barabash, Itay Josef and Kawakami, Erika},
  journal = {Phys. Rev. Lett.},
  volume = {135},
  pages = {087001},
  year = {2025},
  doi = {10.1103/5y8p-qhb4},
  overleaf = {https://www.overleaf.com/read/wnybdtvxsxyk#ca9ad5},
  overleaf_suppl = {https://www.overleaf.com/read/vhmsmhdscrjm#87fba9},
  index = {2024 Rydberg FM},
  note = {Editors' Suggestion},
}

APL

Quantum computing using floating electrons on cryogenic substrates: Potential and challenges

Asher Jennings^* , Xianjing Zhou , Ivan Grytsenko , and Erika Kawakami^*

Appl. Phys. Lett. 124, 120501 (2024).

DOI arXiv Bib Journal

@article{jennings2024perspectives,
  title = {Quantum computing using floating electrons on cryogenic substrates: Potential and challenges},
  author = {Jennings, Asher and Zhou, Xianjing and Grytsenko, Ivan and Kawakami, Erika},
  lab_members = {Zhou},
  journal = {Appl. Phys. Lett.},
  volume = {124},
  pages = {120501},
  year = {2024},
  doi = {10.1063/5.0179700},
  overleaf = {https://www.overleaf.com/read/knxxdvsvhvyt#29ec0d},
  index = {2024 APL Perspectives},
}

PRAppl

Blueprint for quantum computing using electrons on helium

Erika Kawakami^* , Jiabao Chen , Monica Benito , and Denis Konstantinov

Phys. Rev. Applied 20, 054022 (2023).

DOI arXiv Bib Journal

@article{kawakami2023blueprint,
  title = {Blueprint for quantum computing using electrons on helium},
  author = {Kawakami, Erika and Chen, Jiabao and Benito, Monica and Konstantinov, Denis},
  journal = {Phys. Rev. Applied},
  volume = {20},
  pages = {054022},
  year = {2023},
  doi = {10.1103/PhysRevApplied.20.054022},
  overleaf = {https://www.overleaf.com/read/gbxxyfjxmrgq#de6658},
  index = {2023 PRApplied Blueprint},
}