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Displaying 1 - 25 of 104

Measurement of electric-field noise from interchangeable samples with a trapped-ion sensor

November 18, 2021
Author(s)
Kyle McKay, Dustin Hite, Philip D. Kent, Shlomi S. Kotler, Dietrich Leibfried, Daniel Slichter, Andrew C. Wilson, David P. Pappas
We demonstrate the use of a single trapped ion as a sensor to probe electric-field noise from interchangeable test surfaces. As proof of principle, we measure the magnitude and distance dependence of electric-field noise from two ion-trap-like samples with

Perspective: Reproducible coherence characterization of superconducting quantum devices

September 6, 2021
Author(s)
Corey Rae McRae, Joshua Combes, Gregory Stiel, Haozhi Wang, Sheng Xiang Lin, David P. Pappas, Josh Mutus
As the field of superconducting quantum computing approaches maturity, optimization of single-device performance is proving to be a promising avenue toward large-scale quantum computers. However, this optimization is possible only if performance metrics

Cryogenic single-port calibration for superconducting microwave resonator measurements

June 28, 2021
Author(s)
Haozhi Wang, Suren Singh, Corey Rae McRae, Joseph C. Bardin, S.-X. Lin, A. R. Castelli, Y. J. Rosen, David P. Pappas, J. Y. Mutus
Superconducting circuit testing and materials loss characterization requires robust and reliable methods for the extraction of internal and coupling quality factors of microwave resonators. A common method, imposed by limitations on the device design or

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

Materials loss measurements using superconducting microwave resonators

June 9, 2020
Author(s)
Corey Rae H. McRae, Haozhi Wang, Jiansong Gao, Michael R. Vissers, Teresa Brecht, A Dunsworth, David P. Pappas, J. Mutus
The performance of superconducting circuits for quantum computing is limited by materials losses. In particular, coherence times are typically bounded by two-level system (TLS) losses at single photon powers and millikelvin temperatures. The identification

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

Correlating Decoherence in Transmon Qubits: Low Frequency Noise by Single Fluctuators

November 8, 2019
Author(s)
Steffen Schlor, Jurgen Lisenfeld, Clemens Muller, Alexander Bilmes, Andre Schneider, David P. Pappas, Alexey V. Ustinov, Martin Weides
We report on long-term measurements of a highly coherent, nontunable superconducting transmon qubit, revealing low-frequency burst noise in coherence times and qubit transition frequency. We achieve this through a simultaneous measurement of the qubit's

Active protection of a superconducting qubit with an interferometric Josephson isolator

July 17, 2019
Author(s)
Baleegh Abdo, Nicholas T. Bronn, Oblesh Jinka, Salvatore B. Olivadese, Antonio D. Corcoles, Vivekananda P. Adiga, Markus Brink, Russell Lake, Xian Wu, David P. Pappas, Jerry M. Chow
Nonreciprocal microwave devices play critical roles in high-fidelity, quantum-nondemolition (QND) measurement schemes. They impose unidirectional routing of readout signals and protect the quantum systems from unwanted noise originated by the output chain

Crystallographic orientation dependence of work function: carbon adsorption on Au surfaces

April 14, 2019
Author(s)
Dustin A. Hite, Hossein Jooya, X Fan, Kyle S. McKay, David P. Pappas, H.R. Sadeghpour
We show in this work that the work function change due to carbon adatom adsorption is not predominantly affected by the crystallographic orientation of the gold surface. Ab-initio calculations within density-functional theory are performed on carbon

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

Mechanisms for carbon adsorption on Au(110)-(2 x 1): A work function analysis

July 17, 2018
Author(s)
Dustin A. Hite, Hossein Jooya, Kyle S. McKay, Eunja Kim, Philippe F. Weck, David P. Pappas, H.R. Sadeghpour
The variation of the work function upon carbon adsorption on the reconstructed Au(110) surface is measured experimentally and compared to density functional calculations. The adsorption dynamics is simulated with ab-initio molecular dynamics techniques

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

High coherence plane breaking packaging for superconducting qubits

February 7, 2018
Author(s)
David P. Pappas, Xian Wu, Nicholas T. Bronn, Salvatore B. Olivadese, Vivekananda P. Adiga, Jerry M. Chow
Wedemonstrate a pogo pin package for a superconducting quantum processor specifically designed with a nontrivial layout topology (e.g., a center qubit that cannot be accessed from the sides of the chip). Two experiments on two nominally identical

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

Measurements of trapped-ion heating rates with exchangeable surfaces in close proximity

January 15, 2017
Author(s)
Dustin A. Hite, Kyle S. McKay, Shlomi Salman Kotler, Dietrich G. Leibfried, David J. Wineland, David P. Pappas
Electric-field noise from the surfaces of ion-trap electrodes couples to the ion’s charge causing heating of the ion’s motional modes. This heating limits the fidelity of quantum gates implemented in quantum information processing experiments. The exact

Laser-assisted atom probe tomography of Ti/TiN films deposited on Si

December 21, 2016
Author(s)
Norman A. Sanford, Paul T. Blanchard, Ryan M. White, Michael R. Vissers, Albert Davydov, D R. Diercks, David P. Pappas
Laser-assisted atom probe tomography (L-APT) was used to examine superconducting TiN/Ti/TiN trilayer films with nominal respective thicknesses of 5/5/5 (nm). The trilayers were deposited on Si substrates by reactive sputtering. Electron energy loss