Dear QNN Group Members, Alums and Affiliates,

Hope everyone is enjoying the start to Spring!  We are excited to share updates from the QNN group over the last months.  

It has been a while since our last newsletter, so a lot of activity to report.  In particular we want to highlight that Dip Joti Paul received the 2026 Claude Shannon Award from RLE, and Adina Bechhofer the 2026 Samsung Semiconductor Fellowship from EECS.   Also, last November we held our annual group retreat at Endicott house and have included a picture from the event.  As usual, we provide a quick summary of comings and goings, awards, research activity and events below.

 Best regards,
Karl and Donnie

Comings and Goings

The last few months we’ve welcomed the following new group members:

• Dong min Kim, Visiting Scientist
• Zhenyang Xiao, Postdoctoral Associate
• Eileen Xiu, UROP 
• Jaden McKee, UROP
• Berkan Tarak, UROP

The following members have now left and become alumni group members:

• Josh Piety, UROP, graduated!
• Hanson Nguyen, Undergrad researcher, MSRP
• Giorgia Ciuffarella, Polytechnic of Turin & École Polytechnique Fédérale de Lausanne, graduated!
• Gabriel LeGuay, Federal Polytechnique School of Zurich, graduated!
• Owen Medeiros, working as a Superconducting Electronics Architect at MIT Lincoln Lab

Awards

• Dip Joti Paul has received the 2026 Claude E. Shannon Award!
• Adina Bechhoffer has received the Samsung Semiconductor Fellowship!

Theses!

G. Ciuffarella, “Infrared-Enhanced Electron Emission from Nanoantennas for Optical Detection,” Ecole Polytechnique Federale de Lausanne and Massachusetts Institute of Technology, 2025.

G. Le Guay, “Reconfigurable superconducting logic gate: From photon-driven operation to electro-optic modulation,” Master’s Thesis, Swiss Federal Institute of Technology, Zurich and Massachusetts Institute of Technology, 2025.

Publications (6/1/25-1/31/26)

R. A. Foster, S. Kandeh, O. Medeiros, A. Simon, M. Castellani, and K. K. Berggren, “Time-tagging data acquisition system for testing superconducting electronics based on an RFSoC and custom analog frontend,” J. Inst., vol. 20, no. 09, p. P09018, Sep. 2025, doi: 10.1088/1748-0221/20/09/P09018.

R. Jing et al., “Bolometric Superconducting Optical Nanoscopy (BOSON),” Phys. Rev. X, vol. 15, no. 3, p. 031027, Jul. 2025, doi: 10.1103/f13d-dpdn.

V. Karam et al., “Parameter extraction for a SPICE model of an hTron superconducting thermal switch,” Phys. Rev. Appl., vol. 24, no. 2, p. 024020, Aug. 2025, doi: http://dx.doi.org/10.1103/jdzc-7l2x.

O. Medeiros et al., “A scalable superconducting nanowire memory array with row–column addressing,” Nat Electron, pp. 1–9, Jan. 2026, doi: 10.1038/s41928-025-01512-0.

H. Nguyen, A. Simon, R. A. Foster, and K. K. Berggren, “Modeling electrothermal feedback of superconducting nanowire single photon detectors in SPICE,” IEEE Trans. Appl. Supercond., vol. 35, no. 9, pp. 1–5, Dec. 2025, doi: 10.1109/TASC.2025.3625542.

D. J. Paul, T. X. Zhou, and K. K. Berggren, “Determination of mid-infrared refractive indices of superconducting thin films using Fourier transform infrared spectroscopy,” Appl. Phys. Lett., vol. 126, no. 25, p. 252601, Jun. 2025, doi: 10.1063/5.0268308.

D. J. Paul, T. X. Zhou, and K. K. Berggren, “Photolithography-compatible three-terminal superconducting switch for driving CMOS loads,” Phys. Rev. Appl., vol. 24, no. 2, p. 024060, Aug. 2025, doi: 10.1103/261b-37xx.

F. Ritzkowsky, M. Yeung, G. L. Dolso, L.-T. Chou, and P. D. Keathley, “High-repetition rate, CEP-stable shortwave infrared source with two-cycle pulses for field-resolved spectroscopy,” J. Opt. Soc. Am. B, JOSAB, vol. 43, no. 1, pp. 207–212, Jan. 2026, doi: 10.1364/JOSAB.580422.

Z. Scherübl et al., “Multimode Operation of a Superconducting Nanowire Switch in the Nanosecond Regime,” ACS Nano, vol. 19, no. 32, pp. 29207–29215, Aug. 2025, doi: 10.1021/acsnano.5c03718.

A. Simon et al., “Ab initio modeling of nonequilibrium dynamics in superconducting detectors and qubits,” Phys. Rev. B, vol. 112, no. 17, p. 174512, Nov. 2025, doi: 10.1103/3m2k-mzr6.

J. W. Simonaitis, J. A. Alongi, B. Slayton, W. P. Putnam, K. K. Berggren, and P. D. Keathley, “Electron energy loss spectroscopy of two-dimensional materials in a scanning electron microscope,” Phys. Rev. B, vol. 112, no. 23, p. 235421, Dec. 2025, doi: 10.1103/tdfh-1ppp.<

Conferences & Proceedings (6/1/25-1/31/26)

K. K. Berggren, “Superconducting Nanowire Single-Photon Detectors for Quantum Sensing: From Photon-Number Resolution to Dark-Matter Detection,” presented at the Munich Conference on Quantum Science & Technology, Kufstein, Austria, Jun. 05, 2025. [Online]. Available: https://www.youtube.com/watch?v=-DgP-F5uu1A

K. K. Berggren, “Superconducting Nanostrip Single-Photon Detectors,” presented at the Low-Temperature Quantum Detectors 2025, Helsinki, Finland, Aug. 06, 2025.

K. K. Berggren, “Superconducting Nanowire Single-Photon Detectors,” presented at the Optica Incubator on Cryogenic Integrated Photonics for Classical and Quantum Systems, Washington, DC, Sep. 11, 2025.

K. K. Berggren, “Superconducting Cryotron-Like Electronic Devices and Circuits,” presented at the EUCAS 2025, Porto, Portugal, Sep. 23, 2025.

K. K. Berggren, “Superconducting Nanowire Single-Photon Detectors for Quantum Sensing: From Photon-Number Resolution to Dark-Matter Detection,” presented at the Q-FARM Seminar, Stanford University, California., Oct. 01, 2025.

K. K. Berggren, “Superconducting Detectors and Electronics for Quantum Sensing and Applications in Space,” presented at the Detector Technology Seminar, NASA Goddard Space Flight Center, Virtual, Jan. 14, 2026.

L. C. Blackburn, “SuperLoop: Architecture Modeling for Superconducting AI Accelerators,” presented at the EUCAS 2025, Porto, Portugal, Sep. 22, 2025.

M. Castellani, “Superconducting Nanowire Electronic Devices and Circuits,” presented at the International Conference on Superconductor Materials and Metama- terials for Quantum Hardware: Devices, Circuits, and Systems, Glasgow, UK, Nov. 2025.

R. A. Foster, “Fast numerical methods for the Usadel equation,” presented at the EUCAS 2025, Porto, Portugal, Sep. 22, 2025.

R. A. Foster, “Fast numerical methods for the Usadel equation,” TU Graz, Oct. 15, 2025.

F. Incalza, “Superconducting Nanowire Single-Photon Detectors Fabricated on Epitaxial NbN Thin Films Grown by Sputtering,” presented at the European Conference on Applied Superconductivity (EUCAS 2025), Munich, Germany, Sep. 2025.

Reed A. Foster, “Scalable superconducting multilayer process for digital imager readout with nanocryotrons,” presented at the MARC, Brettn Woods, NH, Jan. 27, 2026.

A. Simon, “Ab initio modeling of superconducting devices,” presented at the EUCAS, Porto, Portugal, Aug. 14, 2025.

A. Simon, “Ab initio modeling of superconducting devices,” TU Graz, Oct. 15, 2025.

F. Ritzkowsky, M. Yeung, G. L. Dolso, L.-T. Chuo, and P. D. Keathley, “High-Repetition Rate 2.3-Cycle Shortwave-Infrared Source for Next-Generation Field-Resolved Spectroscopy,” in 2025 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), Jun. 2025. doi: 10.1109/CLEO/Europe-EQEC65582.2025.11109943.

A. Bechhofer, J. Simonaitis, F. Ritzkowsky, L. Daniel, K. K. Berggren, and P. D. Keathley, “Exploring Parasitics and Coupling between Optically Driven Nanoantennas and Interconnects in Petahertz Electronic Circuits,” in 2025 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), Munich, Germany, Jun. 2025. doi: 10.1109/CLEO/Europe-EQEC65582.2025.11109477.

P. D. Keathley, “Nanoscale Petahertz-Electronics for Field-Resolved Spectroscopy,” in 2025 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), Munich, Germany: IEEE, Jun. 2025. doi: 10.1109/CLEO/Europe-EQEC65582.2025.11109586.

Preprints (6/1/25-1/31/26)

F. Incalza et al., “Fast-Recovery Epitaxial NbN Superconducting Nanowire Single-Photon Detectors with Saturated Efficiency at 1550 nm in Liquid Helium,” Dec. 19, 2025, arXiv:2512.18063. doi: 10.48550/arXiv.2512.18063.