Related Experiment Video
Updated: Jul 16, 2025
05:39
Scalable Quantum Integrated Circuits on Superconducting Two-Dimensional Electron Gas Platform
Published on: August 2, 2019
9.7K
Nb/a-Si/Nb-junction Josephson arbitrary waveform synthesizers for quantum information
David Olaya1, John Biesecker2, Manuel Castellanos-Beltran2
1Department of Physics at the University of Colorado, Boulder, CO; RF Technology Division of the National Institute of Standards and Technology, Boulder, CO, USA.
IEEE Transactions on Applied Superconductivity : a Publication of the IEEE Superconductivity Committee
|September 18, 2023
Summary
We developed Josephson arbitrary waveform synthesizers (JAWS) using externally-shunted junctions for a wider operating temperature range below 4 K. This advancement improves temperature stability for precise qubit control and calibration in cryogenic environments.
Area of Science:
- Superconducting quantum electronics
- Cryogenic engineering
- Quantum computing hardware
Background:
- Josephson arbitrary waveform synthesizers (JAWS) are crucial for controlling superconducting qubits.
- Traditional JAWS use self-shunted junctions, limiting their operating temperature range and stability.
- Improved temperature stability and circuit density are needed for advanced quantum applications.
Purpose of the Study:
- To demonstrate Josephson arbitrary waveform synthesizers (JAWS) with an enhanced operating temperature range below 4 K.
- To improve the temperature stability of JAWS by using externally-shunted junctions.
- To develop high-density JAWS circuits for qubit control and calibration.
Main Methods:
- Fabrication of Nb/a-Si/Nb Josephson junctions with externally-shunted PdAu resistors.
- Development of vertical stud resistors for milliohm shunt resistance and compact footprint.
- Design, fabrication, and testing of a JAWS circuit with 4650 stacked junctions.
- Evaluation of resistor performance from 3.8 K down to 20 mK.
Main Results:
- Externally-shunted junctions exhibit improved critical current temperature stability compared to self-shunted junctions.
- Vertical stud resistors achieve required shunt resistance with a small footprint suitable for high-density arrays.
- Tested JAWS circuit with 4650 stacked junctions shows stable operation and Shapiro steps.
- Performance evaluated down to 20 mK, demonstrating suitability for qubit control stages.
Conclusions:
- Externally-shunted Nb/a-Si/Nb junctions offer enhanced temperature stability for JAWS below 4 K.
- Novel vertical stud resistors enable high-density integration of JAWS circuits.
- The developed JAWS technology is suitable for precise control and calibration of qubits at millikelvin temperatures.
Keywords:
Josephson devicesJosephson junctionsfabrication processsingle flux quantumsuperconducting electronicsMore Related Videos
Related Concept Videos
01:27Biasing of Metal-Semiconductor Junctions
279
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
279
01:16Biasing of P-N Junction
590
The operation of a p-n junction diode involves various biasing conditions, including forward bias, reverse bias, and equilibrium.
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
590
01:13Phasor Arithmetics
327
Phasors and their corresponding sinusoids are interrelated, offering unique insights into the behavior of alternating current (AC) circuits. One way to understand this relationship is through the operations of differentiation and integration in both the time and phasor domains.
When the derivative of a sinusoid is taken in the time domain, it transforms into its corresponding phasor multiplied by j-omega (jω) in the phasor domain, where j is the imaginary unit, and ω is the angular...
When the derivative of a sinusoid is taken in the time domain, it transforms into its corresponding phasor multiplied by j-omega (jω) in the phasor domain, where j is the imaginary unit, and ω is the angular...
327
01:30Oscillations In An LC Circuit
2.3K
An idealized LC circuit of zero resistance can oscillate without any source of emf by shifting the energy stored in the circuit between the electric and magnetic fields. In such an LC circuit, if the capacitor contains a charge q before the switch is closed, then all the energy of the circuit is initially stored in the electric field of the capacitor. This energy is given by
2.3K
01:22Bipolar Junction Transistor
804
Bipolar Junction Transistors (BJTs) are essential elements in electronic circuits, playing a crucial role in the functionality of amplifiers, memories, and microprocessors. These transistors can be designed as NPN or PNP based on their doping patterns. They consist of three layers: the emitter, base, and collector. The configuration of these layers and their respective doping levels—with N-type or P-type impurities—define the transistor's type and its operational...
804
01:11P-N junction
567
A p-n junction is formed when p-type and n-type semiconductor materials are joined together. At the interface of the p-n junction, holes from the p-side and electrons from the n-side begin to diffuse into the opposite sides due to the concentration gradient. This diffusion of carriers leads to a region around the junction where there are no free charge carriers, known as the depletion region. The charge density within the depletion region for the n-side and p-side can be described by the...
567