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Search Publications by: Pete Hopkins (Fed)

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Displaying 1 - 25 of 31

Josephson Sampler Response using a Binary Search Algorithm

January 19, 2024
Author(s)
BART VAN ZEGHBROECK, Logan Howe, Pete Hopkins
This paper presents the use of a binary search algorithm to obtain the simulated response of a superconducting Josephson junction-based sampler. In the absence of noise, this simple approach is superior to mimicking the experimental approach of using an

Single Flux Quantum-Based Digital Control of Superconducting Qubits in a Multi-Chip Module

June 24, 2023
Author(s)
Chuanhong Liu, Robert McDermott, Britton Plourde, Andrew Ballard, Jonathan DuBois, Pete Hopkins, David Olaya, John Biesecker, Samuel P. Benz, Dan Schmidt, Joel Ullom
The single flux quantum (SFQ) digital superconducting logic family has been proposed as a practical approach for controlling next-generation superconducting qubit arrays with more favorable scaling properties compared to conventional microwave-based

Systematic Improvements in Transmon Qubit Coherence enabled by Niobium Surface Encapsulation

June 14, 2023
Author(s)
Mustafa BAL, Akshay Murthy, Francesco Crisa, Shaojiang Zhu, Florent Lecocq, Joe Aumentado, Joel Ullom, Pete Hopkins
We present a novel transmon qubit fabrication technique that yields systematic improvements in T1 coherence times. In this study, the devices are fabricated using a novel encapsulation strategy that involves passivating the surface of niobium and thereby

Nb/a-Si/Nb-junction Josephson-based arbitrary waveform synthesizers for quantum information

February 24, 2023
Author(s)
David Olaya, John Biesecker, Manuel Castellanos Beltran, Adam Sirois, Paul Dresselhaus, Samuel P. Benz, Pete Hopkins, Logan Howe
We demonstrate Josephson arbitrary waveform synthesizers (JAWS) with increased operating temperature range for temperatures below 4 K. These JAWS synthesizers were fabricated with externally-shunted Nb/a-Si/Nb junctions whose critical current exhibits

Measurement Challenges for Scaling Superconductor-based Quantum Computers

June 23, 2022
Author(s)
Pete Hopkins, Manuel Castellanos Beltran, John Biesecker, Paul Dresselhaus, Anna Fox, Logan Howe, David Olaya, Adam Sirois, Dylan Williams, Samuel P. Benz, Alirio De Jesus Soares Boaventura, Justus Brevik
Global investment in the research and development of quantum information systems by industry, government, and academic institutions continues to accelerate and is expected to reach over $16B by 2027 [1]. Systems based on optical photons, atoms or ions

Digital Control of Superconducting Qubit Using a Josephson Pulse Generator at 3K

March 25, 2022
Author(s)
Logan Howe, Manuel Castellanos Beltran, Adam Sirois, David Olaya, John Biesecker, Paul Dresselhaus, Samuel P. Benz, Pete Hopkins
Scaling of quantum computers to fault-tolerant levels relies critically on the integration of energy-efficient, stable, and reproducible qubit control and readout electronics. In comparison to traditional semiconductor-control electronics (TSCE) located at

Cryogenic Characterization of a Superconductor Quantum-Based Microwave Reference Source for Communications and Quantum Information

October 13, 2021
Author(s)
Alirio De Jesus Soares Boaventura, Justus Brevik, Dylan Williams, Nathan Flowers-Jacobs, Manuel Castellanos Beltran, Anna Fox, Pete Hopkins, Paul Dresselhaus, Samuel P. Benz
We are developing a new instrument, the RF Josephson arbitrary waveform synthesizer (RF-JAWS), for communications metrology and quantum information applications. An important aspect of the RF-JAWS design is the accurate and traceable characterization of

Single-Flux-Quantum Multiplier Circuits for Synthesizing Gigahertz Waveforms With Quantum-Based Accuracy

February 3, 2021
Author(s)
Manuel C. Castellanos Beltran, David I. Olaya, Adam J. Sirois, Christine A. Donnelly, Paul Dresselhaus, Samuel Benz, Peter F. Hopkins
We designed, simulated, and experimentally demonstrated components for a microwave frequency digital-to-analog converter (DAC) based on rapid single flux quantum (RSFQ) circuits and a superconducting amplifier based on SQUID stacks. These are key

Josephson Microwave Sources Applied to Quantum Information Systems

December 18, 2020
Author(s)
Adam J. Sirois, Manuel C. Castellanos Beltran, Anna E. Fox, Samuel P. Benz, Peter F. Hopkins
Quantum computers with thousands or millions of qubits will require a scalable solution for qubit control and readout electronics. Colocating these electronics at millikelvin temperatures has been proposed and demonstrated, but there exist significant

Cryogenic Calibration of a Quantum-based Radio Frequency Source

November 2, 2020
Author(s)
Alirio De Jesus Soares Boaventura, Justus A. Brevik, Dylan Williams, Anna E. Fox, Manuel C. Castellanos Beltran, Peter F. Hopkins, Paul D. Dresselhaus, Samuel P. Benz
We report on the calibration of quantum-based radio frequency waveforms generated by a Josephson arbitrary waveform synthesizer system. We measure these waveforms using a vector network analyzer and calibrate them at 4 K using a custom-designed cryogenic

Cryogenic Calibration of a Quantum-based Radio Frequency Source

November 2, 2020
Author(s)
Alirio De Jesus Soares Boaventura, Justus Brevik, Dylan Williams, Anna Fox, Manuel Castellanos Beltran, Pete Hopkins, Paul Dresselhaus, Samuel P. Benz
We report on the calibration of quantum-based radio frequency waveforms generated by a Josephson arbitrary waveform synthesizer system. We measure these waveforms using a vector network analyzer and calibrate them at 4 K using a custom-designed cryogenic

A Cryogenic Quantum-Based RF Source

September 10, 2020
Author(s)
Justus A. Brevik, Alirio De Jesus Soares Boaventura, Manuel C. Castellanos Beltran, Christine A. Donnelly, Nathan E. Flowers-Jacobs, Anna E. Fox, Peter F. Hopkins, Paul D. Dresselhaus, Dylan Williams, Samuel P. Benz
We performed a preliminary calibrated measurement of the output power of a Josephson arbitrary waveform synthesizer up to 1 GHz. We present the results and measurement procedure for generating quantum-based signals using an array of Josephson junctions

Microwave Modeling and Characterization of Superconductive Circuits for Quantum Voltage Standard Applications at 4 Kelvin

February 10, 2020
Author(s)
Alirio De Jesus Soares Boaventura, Dylan F. Williams, Richard A. Chamberlin, Jerome G. Cheron, Anna E. Fox, Paul D. Dresselhaus, Peter F. Hopkins, Ian W. Haygood, Samuel P. Benz
We developed a cryogenic multiline thru-reflect-line (TRL) calibration kit for microwave characterizing of superconductive circuits used in the Josephson arbitrary waveform synthesizer of the national institute of standards and technology (NIST). We also

Synaptic weighting in single flux quantum neuromorphic computing

January 22, 2020
Author(s)
Michael L. Schneider, Christine A. Donnelly, Ian W. Haygood, Alex Wynn, Stephen E. Russek, Manuel C. Castellanos Beltran, Paul D. Dresselhaus, Peter F. Hopkins, Matthew R. Pufall, William H. Rippard
Josephson junctions act as a natural spiking neuron-like device for neuromorphic computing. By leveraging the advances recently demonstrated in digital single flux quantum (SFQ) circuits and using recently demonstrated magnetic Josephson junction (MJJ)

1 GHz Waveform Synthesis with Josephson Arrays

July 31, 2019
Author(s)
Christine A. Donnelly, Justus A. Brevik, Nathan E. Flowers-Jacobs, Peter F. Hopkins, Paul D. Dresselhaus, Samuel P. Benz
For the first time, we synthesize single- and multiple-tone waveforms at gigahertz frequencies from arrays of Josephson junctions and demonstrate quantum-locked operation over a range of experimental input parameters. We first use a lumped-element circuit

1 GHz Waveform Synthesis With Josephson Junction Arrays

July 31, 2019
Author(s)
Christine A. Donnelly, Nathan E. Flowers-Jacobs, Justus A. Brevik, Anna E. Fox, Paul D. Dresselhaus, Peter F. Hopkins, Samuel P. Benz
We synthesize single- and multiple-tone waveforms at gigahertz frequencies from arrays of Josephson junctions and demonstrate their quantum-locked operation over a range of experimental input parameters. We first use a lumped-element circuit to synthesize

Quantized Pulse Propagation in Josephson Junction Arrays

July 23, 2019
Author(s)
Christine A. Donnelly, Justus Brevik, Nathan Flowers-Jacobs, Anna Fox, Paul Dresselhaus, Peter F. Hopkins, Samuel Benz
We present time-domain electrical measurements and simulations of the quantized voltage pulses that are generated from series-connected Josephson junction (JJ) arrays. The transmission delay of the JJ array can lead to a broadening of the net output pulse

Planarized process for single-flux-quantum circuits with self-shunted Nb/NbxSi1-x/Nb Josephson junctions

February 18, 2019
Author(s)
David I. Olaya, Manuel C. Castellanos Beltran, Javier Pulecio, John P. Biesecker, Soroush Khadem, Theodore Lewitt, Peter F. Hopkins, Paul D. Dresselhaus, Samuel P. Benz
We describe the single-flux-quantum (SFQ) circuit fabrication process employed at NIST's Boulder Microfabrication Facility. The process includes four superconducting metal layers, one palladium-gold resistor layer, and a contact pad layer. Chemical

RF waveform synthesizers with quantum-based voltage accuracy for communications metrology

February 11, 2019
Author(s)
Peter F. Hopkins, Justus A. Brevik, Manuel C. Castellanos Beltran, Nathan E. Flowers-Jacobs, Anna E. Fox, David I. Olaya, Christine A. Donnelly, Paul D. Dresselhaus, Samuel P. Benz
We report on NIST’s development of Josephson junction-based programmable reference sources to synthesize quantum-accurate, spectrally-pure waveforms for characterizing and improving next generation communication devices and systems. The goal is to provide

Stacked Josephson Junctions as inductors for SFQ circuits

February 11, 2019
Author(s)
Manuel C. Castellanos Beltran, David I. Olaya, Adam J. Sirois, Paul D. Dresselhaus, Samuel P. Benz, Peter F. Hopkins
In order for Single Flux Quantum (SFQ) circuits to be scaled to densities needed for large-scale integration, typical lithographically-patterned circuit components should be made to be as compact as possible. In this work, we characterize the performance

Energy efficient single flux quantum based neuromorphic computing

November 8, 2018
Author(s)
Michael Schneider, Christine A. Donnelly, Stephen E. Russek, Burm Baek, Matthew Pufall, Pete Hopkins, William Rippard
Many neuromorphic hardware technologies are being explored for their potential to increase the efficiency of computing certain problems, and thus facilitate machine learning with greater energy efficiency and or with more complexity. Among the technologies