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Displaying 1 - 10 of 10

Cryogenic microwave loss in epitaxial Al/GaAs/Al trilayers for superconducting circuits

January 14, 2021
Author(s)
Corey Rae McRae, A. McFadden, Ruichen Zhao, Haozhi Wang, Junling Long, Tongyu Zhao, Sungoh Park, Mustafa Bal, Christopher J. Palmstrom, David P. Pappas
Epitaxially grown superconductor/dielectric/superconductor trilayers have the potential to form high-performance superconducting quantum devices and may even allow scalable superconducting quantum computing with low-surface-area qubits such as the merged

Overlap junctions for superconducting quantum electronics and amplifiers

May 25, 2020
Author(s)
Mustafa Bal, Junling Long, Ruichen Zhao, Haozhi Wang, Sungoh Park, Corey Rae H. McRae, Tongyu Zhao, Russell Lake, Daniil Frolov, Roman Pilipenko, Silvia Zorzetti, Alexander Romanenko, David P. Pappas
Due to their unique properties as lossless, nonlinear circuit elements, Josephson junctions lie at the heart of superconducting quantum information processing. Previously, we demonstrated a two-layer, submicrometer-scale overlap junction fabrication

Amplitude and frequency sensing of microwave fields with a superconducting transmon qudit

May 21, 2020
Author(s)
Maximilian Kristen, Andre Schneider, Alexander Stehli, Tim Wolz, Sergey Danilin, Hsiang S. Ku, Junling Long, Xian Wu, Russell Lake, David P. Pappas, Alexey V. Ustinov, Martin Weides
Experiments with superconducting circuits require careful calibration of the applied pulses and fields over a large frequency range. This remains an ongoing challenge as commercial semiconductor electronics are not able to probe signals arriving at the

Dielectric loss extraction for superconducting microwave resonators

May 5, 2020
Author(s)
Corey Rae H. McRae, Russell Lake, Junling Long, Mustafa Bal, Xian Wu, Battogtokh Jugdersuren, Thomas Metcalf, Xiao Liu, David P. Pappas
The investigation of two-level-state (TLS) loss in dielectric materials and interfaces remains at the forefront of materials research in superconducting quantum circuits. We demonstrate a method of TLS loss extraction of a thin film dielectric by measuring

Microwave-based arbitrary cphase gates for transmon qubits

January 17, 2020
Author(s)
George S. Barron, Fernando A. Calderon-Vargas, Junling Long, David P. Pappas, Sophia E. Economou
Superconducting transmon qubits are of great interest for quantum computing and quantum simulation. A key component of quantum chemistry simulation algorithms is breaking up the evolution into small steps, which naturally leads to the need for nonmaximally

Kinetic Inductance Traveling Wave Amplifiers For Multiplexed Qubit Readout

December 10, 2018
Author(s)
Leonardo Ranzani, K. C. Fong, G. Ribell, Tomas A. Ohki, David P. Pappas, Mustafa Bal, Xian Wu, Robert P. Erickson, Junling Long, Hsiang S. Ku
We describe a kinetic inductance traveling-wave (KIT) amplifier suitable for superconducting quantum information measurements and characterize its wideband scattering and noise properties. We use mechanical microwave switches to calibrate the four

Enhanced superconducting transition temperature in electroplated rhenium

April 30, 2018
Author(s)
David P. Pappas, Don David, Mustafa Bal, Ilke Arslan, Paul T. Blanchard, Ronald B. Goldfarb, Dustin A. Hite, Hsiang S. Ku, Russell E. Lake, Junling Long, Alexana Roshko, Lee D. Pappas, Britton L. Plourde, Jianguo Wen, Xian Wu, Corey Rae H. McRae
We show that electroplated Re films in multilayers with noble metals such as Cu, Au, and Pd have an enhanced superconducting critical temperature relative to previous methods of preparing Re. The dc resistance and magnetic susceptibility indicate a critical

Overlap junctions for high coherence superconducting qubits

May 26, 2017
Author(s)
Xian Wu, Junling Long, Hsiang S. Ku, Russell Lake, Mustafa Bal, David P. Pappas
Fabrication of sub-micron Josephson junctions is demonstrated using standard processing techniques for high-coherence, superconducting qubits. These junctions are made in two separate lithography steps with normal-angle evaporation. Most significantly

Qubit gates using hyperbolic secant pulses

April 7, 2017
Author(s)
Hsiang S. Ku, Junling Long, Xian Wu, Mustafa Bal, Russell Lake, Edwin Barnes, Sophia Economou, David P. Pappas
It has been known since the early days of quantum mechanics that hyperbolic secant pulses possess the unique property that they can perform cyclic evolution on two-level quantum systems independently of the pulse detuning. More recently, it was realized