A near-quantum-limited Josephson traveling-wave parametric amplifier.
Detecting single-photon level signals—carriers of both classical and quantum information—is particularly challenging for low-energy microwave frequency excitations. Here we introduce a superconducting amplifier based on a Josephson junction transmission line. Unlike current standing-wave parametric amplifiers, this traveling wave architecture robustly achieves high gain over a bandwidth of several gigahertz with sufficient dynamic range to read out 20 superconducting qubits. To achieve this performance, we introduce a subwavelength resonant phase-matching technique that enables the creation of nonlinear microwave devices with unique dispersion relations. We benchmark the amplifier with weak measurements, obtaining a high quantum efficiency of 75% (70% including noise added by amplifiers following the Josephson amplifier). With a flexible design based on compact lumped elements, this Josephson amplifier has broad applicability to microwave metrology and quantum optics.
Quantum Nanoelectronics Laboratory, University of California, Berkeley, Berkeley, CA 94720, USA. Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. chris.macklin@berkeley.edu.
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Macklin
Nanoscale Science and Engineering Center, University of California, Berkeley, Berkeley, CA 94720, USA.
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O'Brien
Massachusetts Institute of Technology (MIT) Lincoln Laboratory, 244 Wood Street, Lexington, MA 02420, USA.
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Hover
Quantum Nanoelectronics Laboratory, University of California, Berkeley, Berkeley, CA 94720, USA.
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Schwartz
Massachusetts Institute of Technology (MIT) Lincoln Laboratory, 244 Wood Street, Lexington, MA 02420, USA.
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Bolkhovsky
Nanoscale Science and Engineering Center, University of California, Berkeley, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. Department of Physics, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
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Zhang
Massachusetts Institute of Technology (MIT) Lincoln Laboratory, 244 Wood Street, Lexington, MA 02420, USA. Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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Oliver
Quantum Nanoelectronics Laboratory, University of California, Berkeley, Berkeley, CA 94720, USA.
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Siddiqi