Bulletin of the American Physical Society
APS March Meeting 2020
Volume 65, Number 1
Monday–Friday, March 2–6, 2020; Denver, Colorado
Session A36: Superconducting Qubit Readout, Detection, and Classical Control ElectronicsFocus
|
Hide Abstracts |
Sponsoring Units: DQI Chair: Thomas Ohki, BBN Technologies Room: 601/603 |
Monday, March 2, 2020 8:00AM - 8:36AM |
A36.00001: Control of Transmon Qubits using a Cryogenic CMOS Integrated Circuit Invited Speaker: Joseph Bardin Superconducting quantum processors are controlled and measured in the analog domain and the design of the associated classical-to-quantum interface is critical in optimizing the overall performance of the quantum computer. Control of the processor is achieved using a combination of carefully shaped microwave pulses and high-precision time varying flux biases. Measurement of quantum states is typically achieved using dispersive readout, which requires a low-power pulsed microwave drive and a near quantum-limited readout chain. For control of a single qubit, a typical system employs two high-speed high-resolution (e.g., 1 Gsps/14 bit) digital-to-analog converters (DACs) and a single-sideband modulator to generate microwave control pulses. A third DAC with similar specifications is used for flux-bias control. A typical readout channel may service on the order of five qubits and contains yet another pair of DACs, with a single-sideband modulator employed to generate a stimulus signal. For measurement, the readout chain also employs a series of cryogenic amplifiers followed by further amplification, IQ demodulation, and high-speed digitization at room temperature. For today’s prototype systems with on the order of 50-100 qubits, keeping most of the electronics at room temperature makes sense. However, achieving fault tolerance—a long term goal of the community—will require implementing systems with on the order of 10^6 qubits and today’s brute force control and readout approach will not scale to these levels. Instead, a more integrated approach will be required. In this talk, we will present a review of recent work towards implementing a scalable cryogenic quantum control and readout system using silicon integrated circuit technology. After motivating the work, we will describe the design and characterization of a prototype cryogenic XY controller for transmon qubits. Detailed measurement results will be presented. The talk will conclude with a discussion of future work. |
Monday, March 2, 2020 8:36AM - 8:48AM |
A36.00002: Kalman-based IQ Mixer Calibration for Circuit QED Shan Williams Jolin, Riccardo Borgani, Mats Olov Tholén, David Haviland Quantum measurements with superconducting circuits require the generation and detection of signal frequencies in the 2 - 12 GHz range, where frequency conversion is performed by analog devices known as IQ mixers. These mixers generate unwanted image signals upon upconversion, which crowd the already limited frequency spectrum, and become superimposed with the desired signal upon downconversion. Image signals are particularly problematic for frequency-multiplexed qubits [1] as they are a possible source of dephasing when accidentally driving another qubit. These detrimental effects can be minimized by calibrating the IQ mixers. |
Monday, March 2, 2020 8:48AM - 9:00AM |
A36.00003: Reversible Fluxon Logic with shift registers Waltraut Wustmann, Kevin Osborn Reversible digital logic can improve energy efficiency over irreversible logic. Reversible logic gates in superconducting circuits are currently made in the adiabatic type, where drive fields evolve the bit state, but we are developing Reversible Fluxon Logic (RFL) in the ballistic type – key gates are solely powered by bit state inertia. RFL represents the bit states by the two topological charges (flux polarities) of fluxons in a Long Josephson Junction (LJJ). Ballistic gates consist of at least two LJJ connected by a circuit interface and use a resonant conversion of an input fluxon to and from a localized field at the interface. At the end of this process a new fluxon is created in another LJJ and its polarity may deterministically differ from the input bit, thus enabling bit switching. In simulations 1- and 2-bit RFL gates can restore 97% of the input fluxon energy in the output fluxons. While previous RFL 2-bit gates require synchronous input bits, newly developed gates store an internal flux state by which the timing restriction is lifted (asynchronous). This is demonstrated with the shift register – the input state is stored as internal flux while the previously stored flux state transfers to a ballistic output fluxon. We apply a model developed to describe RFL dynamics. |
Monday, March 2, 2020 9:00AM - 9:12AM |
A36.00004: Practical Microwave Direct Digital Synthesis for Superconducting Qubit Control William Kalfus, Diana F. Lee, Spencer Fallek, Guilhem Ribeill, Andrew Wagner, Martin V Gustafsson, Thomas A Ohki, Brian Donovan, Diego Ristè To conduct experiments with higher numbers of superconducting qubits, the availability of scalable control hardware is essential. To address this, we have incorporated custom superconducting qubit control logic into off-the-shelf hardware employing direct RF synthesis at 5 GHz for low-noise and low-latency pulse generation up to 7.5 GHz. Our approach eliminates the need for upconversion (which requires precise calibration to prevent leakage) and highly stable microwave sources (which can be expensive). The wide bandwidth enables efficient experiment configurations, such as control and readout using a single channel. We characterize the performance of the hardware using a five-transmon IBM device and demonstrate no additional decoherence or gate error for one- and two-qubit gates compared to traditional configurations, establishing a foundation for scalable quantum control beyond intermediate-scale systems. |
Monday, March 2, 2020 9:12AM - 9:24AM |
A36.00005: A scalable FPGA platform for qubit readout and control Mats Tholen, Riccardo Borgani, Shan Williams Jolin, David Haviland Readout and control of superconducting qubits requires high bandwidth signal generation, acquisition and processing, together with the possibility of implementing low latency feedback. These requirements are fulfilled in a new category of Field Programmable Gate Arrays (FPGA) designed for applications in software-defined radio. We adapted the Xilinx Zynq Ultrascale+ RFSoC hardware platform by implementing firmware for pulsed control and readout of qubit circuits. We have also implemented firmware for coherent multifrequency modulation and demodulation of continuous signals. Using the second Nyqvist band we perform direct digital synthesis and measurement at microwave frequencies, without analog mixers. With 8 analog input and 8 analog output channels, on-chip integration of DAC, ADC and FPGA, the RFSoC is a promising new platform for experiments with circuit QED. |
Monday, March 2, 2020 9:24AM - 9:36AM |
A36.00006: High-density cryogenic wiring for superconducting qubits Steven Weber, John Cummings, Jovi Miloshi, Kyle J Thompson, John Rokosz, Andrew James Kerman, William Oliver As superconducting quantum processors continue to scale up in size, it becomes increasingly challenging to route the required number of control lines through a dilution refrigerator to the qubit chip. In this presentation, we will discuss our efforts to develop high-density fridge wiring for use in next-generation quantum annealers. Our wiring solution is based on flexible multi-channel cables with a stripline geometry, designed to achieve low crosstalk and moderate bandwidth. We will describe the electrical performance of these cables, as well as other design considerations such as thermal management. |
Monday, March 2, 2020 9:36AM - 9:48AM |
A36.00007: Single Flux Quantum based electronics for control and readout of superconducting qubits. Manuel Castellanos-Beltran, Adam J. Sirois, Junling Long, Anna Fox, Dan Schmidt, Paul David Dresselhaus, Peter F. Hopkins, Joel N Ullom, David Pappas, Samuel P Benz Superconducting quantum information systems require a mix of continuous-wave AC, pulse-modulated AC, and DC signals for control and readout. There are significant advantages in terms of scaling, physical footprint, latency, signal integrity, and power consumption by moving these sources to 4 K or below, inside the cryostat. In this talk we present an experimental demonstration generating spectroscopy tones at 4 K to measure a transmon qubit’s energy level spacings at 100 mK. The spectroscopy tones are generated by a series of Josephson junctions at 4 K driven by a sigma-delta pulse stream from room temperature. This experiment was our first step in optimizing the Josephson arbitrary waveform synthesizer (JAWS) circuit for controlling quantum systems in a scalable manner. We also discuss further steps needed to generate pulsed signals for qubit preparation, cryogenic readout, and digital superconducting circuits at 4K for signal processing and feedback. |
Monday, March 2, 2020 9:48AM - 10:00AM |
A36.00008: Unconditional reset of superconducting qubits and readout resonators using a quantum-circuit refrigerator Vasilii Sevriuk, Jani Tuorila, Johannes Heinsoo, Caspar Ockeloen-Korppi, Joni Ikonen, Kuan Yen Tan, Eric Hyyppä, Matti Silveri, Matti Partanen, Máté Jenei, Giacomo Catto, Timm Mörstedt, Leif Grönberg, Jan Goetz, Mikko Mottonen In quantum information processing with logical qubits, increasing the clock rate of the error correction cycles improves the qubit fidelity. The clock rate is limited by the duration of logical gates, qubit state readout, and initialization of qubits and readout circuits. Linear and non-linear superconducting resonators can be quickly initialized using a quantum-circuit refrigerator based on fast voltage pulsing of an SINIS junction [1,2]. We discuss our latest results to this end. |
Monday, March 2, 2020 10:00AM - 10:12AM |
A36.00009: Simple, smooth 50ns QND circuit-QED measurement pulses Felix Motzoi, Christian Dickel, Lukas F Buchmann We demonstrate a technique for greatly reducing the duration and error in circuit QED measurement tasks. We show how to suppress different errors including state discrimination, cavity reset, non-linear cavity effects, bandwidth, filtering, all while retaining QND-ness and staying within a single quadrature. The technique works for a variety of different circuit configurations, including Purcell filters, where two different cavities need to be simultaneously emptied. Moreover, the speed and quantum non-demolition nature is retained as one scales up to more qubits or quantum states, providing a blueprint for scaling up to simultaneously measure leakage state populations, multiple qubits, or multiple network modes. We show for realistic circuit parameters that not only speed can be improved by an order of magnitude but errors as well with 99.9% fidelity well within reach. The technique can be understood in terms of control-theoretic transfer function formalism or shortcuts to adiabaticity, where we can also leverage the adiabatic methodology to cancel unwanted nonlinear effects such as Kerr nonlinearity. |
Monday, March 2, 2020 10:12AM - 10:24AM |
A36.00010: Predictive feedback for active noise canceling in superconducting quantum processors Amir Karamlou, Antti Vepsalainen, Roni Winik, David K Kim, Jonilyn Yoder, Alexander Melville, Bethany Niedzielski, Terry Philip Orlando, Simon Gustavsson, William Oliver Superconducting qubits are amongst the most promising platforms for building near term practical quantum information processors. However, the coherence time (T2) of these qubits is negatively impacted in the presence of dephasing noise. In this work, we show how to efficiently estimate the noise spectrum experienced by the qubit, employ techniques from machine learning to predict the correlated noise in the future and use fast-feedback with an FPGA to cancel the noise. We propose using this estimate-predict-feedback sequence as a tool to increase gate fidelities while running a quantum circuit. |
Monday, March 2, 2020 10:24AM - 10:36AM |
A36.00011: QubiC - An open FPGA based Qubit Control system Gang Huang, Yilun Xu, Ravi Kaushik Naik, Bradley Mitchell, David Santiago, Irfan Siddiqi As the number of qubits increases, the flexibility and scalability of the control system become one of the issues limiting the experiments to expand. We developed an FPGA based qubit control system named QubiC. The system generates the physical RF pulses which implemented the quantum algorithm and process the readout and present them to the higher level. Multiple FPGAs can be synchronized via optical fiber, making the system scalable. |
Monday, March 2, 2020 10:36AM - 10:48AM |
A36.00012: A Scalable Multi-Channel Cryogenic Controller for Spin Qubits/Transmons with Frequency Multiplexing Capability Implemented in Intel 22nm FinFET Technology Bishnu Patra, Jeroen P. G. van Dijk, Sushil Subramanian, Andrea Corna, Xiao Xue, Charles Jeon, Farhana Sheikh, Esdras Juarez Hernandez, Brando Perez Esparza, Huzaifa Rampurawala, Brent Carlton, Nodar Samkharadze, Surej Ravikumar, Carlos Nieva, Sungwon Kim, Hyung-Jin Lee, Amir Sammak, Giordano Scappucci, Menno Veldhorst, Lieven M Vandersypen, Masoud Babaie, Fabio Sebastiano, Edoardo Charbon, Stefano Pellerano Scaling a fault-tolerant quantum computer to a very large number of qubits is a daunting challenge. Innovation is required in qubit fabrication, integration and control. Current approaches for controlling qubits operating at cryogenic temperature using room-temperature electronics will not scale to large qubit arrays. We have recently proposed to bring integrated electronics close to the qubits at cryogenic temperatures. Leveraging deeply-scaled CMOS process technologies, complex System-on-Chips (SoCs) with digital, analog and RF capabilities can be integrated with sufficiently low power consumption to be compatible with dilution refrigerators. We demonstrate a cryo-CMOS controller SoC designed to operate at 4K and implemented in Intel 22nm FinFET technology. The SoC is capable of addressing 128 frequency-multiplexed qubits across 4 separate channels over 1GHz RF bandwidth from 2 to 20GHz. The maximum output power is -16dBm at 6GHz with 40dB gain control. Such flexibility enables the control of both spin qubits and transmons with the same chip. By operating our cryo-CMOS controller on the 4K plate in a dilution refrigerator also hosting a Si-based qubit sample at 20mK, we demonstrate Rabi oscillations and coherent x-y rotations of the spin qubit at both 13.7 and 17.5GHz. |
Monday, March 2, 2020 10:48AM - 11:00AM |
A36.00013: Design, Modeling, and Measurement of Through-Silicon Via (TSV) Structures for Superconducting Quantum Computing Wayne Woods, Danna Rosenberg, Mollie Schwartz, Donna Yost, Jonilyn Yoder, William Oliver We have integrated high-aspect ratio superconducting through silicon vias (TSVs) into routing and control circuitry for superconducting qubits, as well as for dedicated grounding of on-chip ground planes, and for the elimination of chip box modes. We describe our electromagnetic modeling of TSV-embedded routing elements, and we demonstrate their incorporation into design and measurement of superconducting qubits. We also describe the robust modeling and design methodology we use to optimize the combination of compactness, electrical reflections, and dielectric losses. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700