J. Kedziora, E. Q. Bui, A. Yen, A. E. Lombo, K. Peng, T. J. Weir, K. P. O'Brien. "Reflection-less filter for superconducting quantum circuits" arXiv:2506.20645 (2025)
J. B. Kline, A. Yen, S. Chen, K. P O'Brien. "The Arm Qubit: A Superconducting Qubit Co-Designed for Coherence and Coupling" arXiv:2506.05315 (2025)
J. Wang, K. Peng, J. M. Knecht, G. D. Cunningham, A. E. Lombo, A. Yen, D. A. Zaidenberg, M. Gingras, B. M. Niedzielski, H. Stickler, K. Sliwa, K. Serniak, M. E. Schwartz, W. D. Oliver, K. P. O'Brien. "High-Efficiency, Low-Loss Floquet-mode Traveling Wave Parametric Amplifier" arXiv:2503.11812 (2025)
M. Naghiloo, K. Peng, Y. Ye, G. Cunningham, K. P. O'Brien. "Broadband Microwave Isolation with Adiabatic Mode Conversion in Coupled Superconducting Transmission Lines" arXiv:2103.07793 (2021)
Publications
G. Cunningham, Y. Ye, K. Peng, A. Yen, J. Kedziora, K. P. O'Brien. "Variable Frequency Pulse Generation From Breathers in Josephson Transmission Lines" IEEE Transactions on Applied Superconductivity, vol. 35, no. 7, pp. 1-9, 1701209 (2025). doi:10.1109/TASC.2025.3591399 | arXiv:2505.03689, 1-9 (2025).
Y. Ye, J. B. Kline, A. Yen, G. Cunningham, M. Tan, A. Zang, M. Gingras, B. M. Niedzielski, H. Stickler, K. Serniak, M. E. Schwartz, K. P. O'Brien. "Near-ultrastrong nonlinear light-matter coupling in superconducting circuits" Nature Communications, 16, 1-8, 3799 (2025). doi:10.1038/s41467-025-59152-z | arXiv:2404.19199 , 1-16 (2024). See also: Press Release from MIT News Office
A. Levochkina, I. Chatterjee, P. Darvehi, H. G. Ahmad, P. Mastrovito, D. Massarotti, D. Montemurro, F. Tafuri, G. P. Pepe, K. P. O’Brien, M. Esposito. "Modeling Flux Tunability in Josephson Traveling Wave Parameteric Amplifiers With an Open-Source Frequency-Domain Simulator" IEEE Transactions on Applied Superconductivity, vol. 35, no. 3, pp. 1-6, 0601006 (2025). doi:10.1109/tasc.2025.3552432 | arXiv:2408.17293, 1-6 (2024).
A. Yen, Y. Ye, K. Peng, J. Wang, G. Cunningham, M. Gingras, B. M. Niedzielski, H. Stickler, K. Serniak, M. E. Schwartz, K. P. O'Brien. "Interferometric Purcell suppression of spontaneous emission in a superconducting qubit" Physical Review Applied , 23, 2, 1-12, 024068 (2025). doi: 10.1103/PhysRevApplied.23.024068 | arXiv:2405.10107, 1-11 (2025).
Y. Ye, J. B. Kline, S. Chen, A. Yen, K. P. O’Brien. "Ultrafast superconducting qubit readout with the quarton coupler" Science Advances, 10, 41, 1-17, eado9094 (2024). doi:10.1126/sciadv.ado9094 | arXiv:2402.15664, 1-20 (2024).
A. Yen, Y. Ye, K. Peng, J. Wang, G. Cunningham, M. Gingras, B. M. Niedzielski, H. Stickler, K. Serniak, M. E. Schwartz, K. P. O'Brien. "Directional emission of a readout resonator for qubit measurement" Physical Review Applied , 22, 3, 1-17, 034035 (2024). doi:10.1103/PhysRevApplied.22.034035 | arXiv:2403.01375, 1-16 (2024).
J. Y. Qiu, A. Grimsmo, K. Peng, B. Kannan, B. Lienhard, Y. Sung, P. Krantz, V. Bolkhovsky, G. Calusine, D. Kim, A. Melville, B. M. Niedzielski, J. Yoder, M. E. Schwartz, T. P. Orlando, I. Siddiqi, S. Gustavsson, K. P. O’Brien, W. D. Oliver. "Broadband squeezed microwaves and amplification with a Josephson traveling-wave parametric amplifier" Nature Physics (2023) | arXiv:2201.11261, 1-29 (2022). See also: Press Release from MIT News Office
K. Peng, M. Naghiloo, J. Wang, G. D. Cunningham, Y. Ye, and K. P. O’Brien. "Floquet-Mode Traveling-Wave Parametric Amplifiers" PRX Quantum 3, 020306 (2022)
K. Peng, R. Poore, P. Krantz, D. E. Root, K. P. O'Brien. "X-parameter based design and simulation of Josephson traveling-wave parametric amplifiers for quantum computing applications" IEEE International Conference on Quantum Computing and Engineering (2022) 331-340
J. Ville, A. Morvan, A. Hashim, R. K. Naik, M. Lu, B. Mitchell, J. Kreikebaum, K. P. O'Brien, J. J. Wallman, I. Hincks, J. Emerson, E. Smith, E. Younis, C. Iancu, D. I. Santiago, and I. Siddiqi. "Leveraging randomized compiling for the quantum imaginary-time-evolution algorithm" Physical Review Research 4 033140 (2021).
A. Hashim, R. K. Naik, A. Morvan, J.-L. Ville, B. Mitchell, J. M. Kreikebaum, M. Davis, E. Smith, C. Iancu, K. P. O’Brien, I. Hincks, J. J. Wallman, J. Emerson, and I. Siddiqi. "Randomized Compiling for Scalable Quantum Computing on a Noisy Superconducting Quantum Processor" Phys. Rev. X 11, 041039, 1-12 (2021).
Y. Ye, K. Peng, M. Naghiloo, G. Cunningham, K. P. O'Brien. "Engineering Purely Nonlinear Coupling Using a Quarton" Phys. Rev. Lett. 127, 050502 (2021)
A. Morvan, V. V. Ramasesh, M. S. Blok, J.M. Kreikebaum, K. O'Brien, L. Chen, B. K. Mitchell, R. K. Naik, D. I. Santiago, I. Siddiqi. "Qutrit Randomized Benchmarking" Phys. Rev. Lett. 126, 210504 (2021)
A. Grimsmo, B. Royer, J. M. Kreikebaum, Y. Ye, K. O'Brien, I. Siddiqi, A. Blais. "Quantum Metamaterial for Broadband Detection of Single Microwave Photons" Phys. Rev. Applied 15, 034074 (2021)
M. S. Blok, V. V. Ramasesh, T. Schuster, K. O'Brien, J.M. Kreikebaum, D. Dahlen, A. Morvan, B. Yoshida, N. Y. Yao, I. Siddiqi. "Quantum Information Scrambling on a Superconducting Qutrit Processor" Phys. Rev. X 11, 021010 (2021)
J. M. Kreikebaum, K. P. O'Brien, A. Morvan, I. Siddiqi. "Improving wafer-scale Josephson junction resistance variation in superconducting quantum coherent circuits." Supercond. Sci. Technol. 33 06LT02 (2020) doi:10.1088/1361-6668/ab8617
B. Lienhard, J. Braumüller, W. Woods, D. Rosenberg, G. Calusine, S. Weber, A. Vepsäläinen, K. O'Brien, T. P. Orlando, S. Gustavsson, W. D. Oliver. "Microwave Packaging for Superconducting Qubits." Proceedings of the 2019 IEEE/MTT-S International Microwave Symposium (2019) arXiv:1906.05425
L.M. Procopio, L. A. Rozema, Z. J. Wong, D. R. Hamel, K. O'Brien, X. Zhang, B. Dakić, and P. Walther. "Single-photon test of hyper-complex quantum theories using a metamaterial." Nat. Comm.8, 15044 (2017) doi:10.1038/ncomms15044
Z. J. Wong*, Y. Xu*, J. Kim*, K. O'Brien, Y. Wang, L. Feng, and X. Zhang. "Lasing and anti-lasing in a single cavity." Nat. Phot.10, 796-801 (2016). doi:10.1038/nphoton.2016.216
S. S. Kruk, Z. J. Wong, E. Pshenay-Severin, K. O'Brien, D. Neshev, and Y. S. Kivshar, and X. Zhang. "Magnetic hyperbolic optical metamaterials." Nat. Comm.7 11329 (2016) doi:10.1038/ncomms11329
K. O'Brien, C. Macklin, D. Hover, M. E. Schwartz, V. Bolkhovsky, X. Zhang, W. D. Oliver, I. Siddiqi. "Towards quantum-noise limited multiplexed microwave readout of qubits" Proceedings of the 2016 IEEE/MTT-S International Microwave Symposium (2016)doi:10.1109/MWSYM.2016.7540350
F. J. Diaz, T. Hatakeyama, J. Rho, Y. Wang, K. O'Brien, X. Zhang, C. M. de Sterke, B. T. Kuhlmey, and S. Palomba. "Sensitive method for measuring third order nonlinearities in compact dielectric and hybrid plasmonic waveguides." Opt. Express24, 545-554 (2016). doi:10.1364/OE.24.000545
C. Macklin, K. O'Brien, D. Hover, M. E. Schwartz, V. Bolkhovsky, X. Zhang, W. D. Oliver, I. Siddiqi. "A near-quantum-limited Josephson traveling-wave parametric amplifier." Science350, 307-310 (2015). doi:10.1126/science.aaa8525
M. Mrejen*, H. Suchowski*, T. Hatakeyama*, C. Wu, L. Feng, K. O'Brien, Y. Wang, X. Zhang. "Adiabatic elimination-based coupling control in densely packed subwavelength waveguides." Nat. Comm.6, 7565 (2015). doi:10.1038/ncomms8565
K. O'Brien*, H. Suchowski*, J. Rho, A. Salandrino, B. Kanté, X. Yin, X. Zhang. "Predicting nonlinear properties of metamaterials from the linear response." Nat. Mat.14, 379-383 (2015). doi:10.1038/nmat4214
S. N. David, Y. Zhai, A. M. van der Zande, K. O'Brien, P. Y. Huang, D. A. Chenet, J. C. Hone, X. Zhang, and X. Yin. "Rapid, all-optical crystal orientation imaging of two-dimensional transition metal dichalcogenide monolayers." Appl. Phys. Lett.107, 111902 (2015). doi:10.1063/1.4930232
K. O'Brien, C. Macklin, I. Siddiqi, X. Zhang. "Resonant Phase Matching of Josephson Junction Traveling Wave Parametric Amplifiers." Phys. Rev. Lett.113, 157001 (2014). doi:10.1103/PhysRevLett.113.157001
Z. Ye*, T. Cao*, K. O'Brien, H. Zhu, X. Yin, Y. Wang, S. G. Louie, X. Zhang. "Probing excitonic dark states in single-layer tungsten disulphide." Nature513, 214-218 (2014). doi:10.1038/nature13734
K. O'Brien*, N. D. Lanzillotti-Kimura*, J. Rho, H. Suchowski, X. Yin, X. Zhang. "Ultrafast acousto-plasmonic control and sensing in complex nanostructures." Nat. Comm.5, 4042 (2014). doi:10.1038/ncomms5042
X. Yin*, Z. Ye*, D. A. Chenet*, Y. Ye*, K. O'Brien, J. C. Hone, X. Zhang. "Edge Nonlinear Optics on a MoS2 Atomic Monolayer." Science344, 488-490 (2014). doi:10.1126/science.1250564
H. Suchowski*, K. O'Brien*, Z. J. Wong*, A. Salandrino, X. Yin, X. Zhang. "Phase Mismatch-Free Nonlinear Propagation in Optical Zero-Index Materials." Science342, 1223-1226 (2013). doi:10.1126/science.1244303
B. Kanté, Y. Park, K. O'Brien, D. Shuldman, N. D. Lanzillotti-Kimura, Z. J. Wong, X. Yin, X. Zhang. "Symmetry breaking and optical negative index of closed nanorings." Nat. Comm.3, 1180 (2012). doi:10.1038/ncomms2161
K. O'Brien, N. D. Lanzillotti-Kimura, H. Suchowski, B. Kanté, Y. Park, X. Yin, X. Zhang. "Reflective interferometry for optical metamaterial phase measurements." Opt. Lett.37, 4089-4091 (2012). doi:10.1364/OL.37.004089
B. Kanté, K. O'Brien, A. Niv, X. Yin, X. Zhang. "Proposed isotropic negative index in three-dimensional optical metamaterials." Phys. Rev. B85, 041103 (2012).
doi:10.1103/PhysRevB.85.041103
Theses
E. Bui. "Fabrication of Superconducting Reflectionless Filters for Quantum Microwave Circuits." M.Eng. thesis. Massachusetts Institute of Technology (2025)
J. Kline. "The Arm Qubit for Faster, Higher Fidelity Readout and Gates." M.S. thesis. Massachusetts Institute of Technology (2025)
G. Cunningham. "Magnetic Flux and Nonlinear Dynamics of Classical and Quantum Superconducting Hardware." Ph.D. thesis. Harvard University (2025)
J. Wang. "High-efficiency, low-loss Floquet Josephson Traveling Wave Parametric Amplifier." M.S. thesis. Massachusetts Institute of Technology (2025)
A. Zang. "All Pass Readout With Ring Resonators for Qubit Measurement." M.Eng. thesis. Massachusetts Institute of Technology (2024) Link
Y. Ye. "The Quarton Coupler for Near-Ultrastrong Nonlinear Light-Matter Coupling in Superconducting Circuits." Ph.D. thesis. Massachusetts Institute of Technology (2024) Link
K. Peng. "The Quest for Ideal Quantum Amplifiers." Ph.D. thesis. Massachusetts Institute of Technology (2023) Link
Y. Alec. "Interference Purcell Filter for Fast, Modular, and Hardware-Efficient Quantum Measurement." S.M. thesis. Massachusetts Institute of Technology (2022) Link
Y. Ye. "Nonlinearity engineering with the Quarton." S.M. thesis. Massachusetts Institute of Technology (2020) Link
K. Peng. "Quantum efficiency of Josephson traveling wave parametric amplifiers with many-Mode processes." S.M. thesis. Massachusetts Institute of Technology (2020) Link
K. O'Brien. "Nonlinear Light-Matter Interactions in Metamaterials." University of California, Berkeley (2016) Link