For the existing superconducting qubit devices, constructing the corresponding high-fidelity gate operation after system calibration is a key step to realize quantum computing. As the fifth chapter of the series of “Introduction to physics frontier—superconducting quantum computing”, this paper systematically discusses the physical picture and basic method of constructing superconducting qubit gate operation through microwave pulse, gives a set of construction process of single bit gate operation, and extends the measurement and optimization development of gate operation fidelity. This paper aims to help the physics teachers, senior undergraduates, graduate students, and science and engineering backgrounds interested in superconducting quantum computing readers to systematically understand the whole basic process of superconducting qubit gate construction and gate operation fidelity measurement and optimization.
For the existing superconducting qubit devices, constructing the corresponding high-fidelity gate operation after system calibration is a key step to realize quantum computing. As the fifth chapter of the series of “Introduction to physics frontier—superconducting quantum computing”, this paper systematically discusses the physical picture and basic method of constructing superconducting qubit gate operation through microwave pulse, gives a set of construction process of single bit gate operation, and extends the measurement and optimization development of gate operation fidelity. This paper aims to help the physics teachers, senior undergraduates, graduate students, and science and engineering backgrounds interested in superconducting quantum computing readers to systematically understand the whole basic process of superconducting qubit gate construction and gate operation fidelity measurement and optimization.
The Josephson parametric amplifier is the key to superconducting quantum computing experiments. This article introduces its basic physical principles and provides a detailed discussion on the device physical characteristics, implementation design, and development of Josephson parametric amplifiers. Finally, based on practical experimental experience, an effective method for determining the optimal operating point of Josephson parametric amplifiers was proposed. This article helps readers interested in superconducting quantum computing to comprehensively grasp the experimental methods and system composition of superconducting quantum computing, and has certain reference significance for the design of extremely low temperature signal amplifiers.
In recent years, with the high attention of various technological powers and giants, superconducting quantum computing technology has developed rapidly. In less than 10 years, the decoherence time of a single superconducting qubit has increased by 5 orders of magnitude, from nanoseconds to hundreds of microseconds, and is expected to increase to millisecond or even second levels. The preparation of superconducting qubit chips is the foundation for achieving superconducting quantum computing. As the sixth article in the “Introduction to Physical Frontiers—Superconducting Quantum Computing” series, this article systematically elaborates on the micro-fabrication methods for preparing superconducting qubits and co-auxiliary device chips, and looks forward to the development trend of fabrication methods. Through this article, the aim is to help university physics teachers, senior undergraduate and graduate students, as well as readers with a background in science and engineering who are interested in superconducting quantum computing, systematically understand the micro-fabrication methods and processes for implementing superconducting qubit chips, and gain a comprehensive and practical understanding of superconducting quantum computing technology.
This review aims to provide researchers, experimentalists, and quantum engineers with an updated and technically grounded perspective on the implementation of quantum gates in superconducting NISQ devices. The goal is to establish a comprehensive bridge between theoretical quantum circuit synthesis and its practical, experimental implementation, focusing on superconducting quantum technologies. We systematically examine the diverse landscape of superconducting qubits and processor architectures, ranging from conventional transmons to alternative and unconventional designs, evaluating their unique design trade-offs, connectivity constraints, device physics, and materials impact. Moving from theory to actual implementation, we detail how single- and two-qubit operations are synthesized via microwave-driven and flux-activated pulses. We here present our pulse engineering, wave shaping, calibration workflows, demonstrating how to bridge the gap between abstract gate models and real-world hardware limitations in the direction of a hardware-software co-design framework. To validate these operations, we choose benchmarking methodologies with the purpose to get the more efficient metric for the specific evaluation aspect, including truth tables and quantum process tomography. Therefore, we both discuss the theoretical concepts behind the gate synthesis and show experimental implementation of most fundamental gates by proposing a practical workflow.
High-fidelity control of superconducting qubits requires carefully shaped microwave pulses to avoid several different kinds of error at once. This article is a pedagogical bridging text aimed at upper-level undergraduate and early graduate students who have completed an introductory quantum mechanics course and a first course in quantum computing or quantum information, but who have not yet encountered the physical implementation of qubit gates. We integrate physical intuition for pulse design, analytical gate-level descriptions, and practical hardware considerations into a single, derivation-driven narrative, with explicit learning objectives. We begin with simple pulse envelopes and their spectral properties, showing how finite bandwidth produces leakage outside the computational subspace. This motivates the derivative removal by adiabatic gate (DRAG) technique, which we derive explicitly using the Magnus expansion, obtaining a clear, order-by-order account of which physical error channel appears at which order and why DRAG's cancellation is necessarily incomplete. We discuss the practical hardware realities of control pulse generation, focusing on arbitrary waveform generators (AWG), local oscillators (LO), and IQ mixing. Finally, we extend the discussion to two-qubit operation via the cross-resonance gate, and interpret how driving the control qubit at the target qubit's transition frequency necessarily produces several unwanted interaction terms alongside the desired one, and how successive generations of pulse-engineering strategies have been designed to suppress them.
Quantum computing has received extensive attention worldwide. In recent years, quantum scientists represented by academician Pan Jianwei have made remarkable progress in quantum computing. In the framework of university physics courses, the timely introduction of superconducting quantum computing theory can not only serve as an organic supplement and update to the quantum mechanics section of university physics courses, but also enable undergraduate students to have earlier exposure to the principles of superconducting quantum computing and its potential applications. This article attempts to reflect the basic principles of superconducting quantum computing, such as Josephson effect, macroscopic quantum properties, superconducting quantum bit manipulation, etc., within the framework of university physics courses. In addition, it also attempts to incorporate Josephson junction room temperature resistance measurement into university physics experiments in university physics courses. These attempts not only help guide them to focus on the forefront of national strategic needs, lay the foundation for their future research and work in related fields, but also have certain reference significance for the ideological and political construction of university physics courses.
Designing a qubit architecture is one of the most critical challenges in achieving scalable and fault-tolerant quantum computing as the performance of a quantum computer is heavily dependent on the coherence times, connectivity and low noise environments. Superconducting qubits have emerged as a frontrunner among many competing technologies, primarily because of their speed of operations, relatively well-developed and offer a promising path toward scalability. Here, we address the challenges of optimizing superconducting qubit hardware through the development of a comprehensive theoretical framework that spans the entire process - from design to the calibration of hardware through quantum gate execution. We develop this framework in four key steps: circuit design, electromagnetic analysis, spectral analysis, and pulse sequencing with calibration. We first refine the qubit's core components - such as capacitance, Josephson junctions, and resonators - to set the foundation for strong performance. The electromagnetic analysis, using the Lumped Oscillator model, allows us to map out the capacitance matrix, ensuring that we minimize spectral dispersion while maximizing coherence times. Following this, we conduct spectral analysis to fine-tune the qubit's frequency spectrum and coherence properties, ensuring that the qubit parameters are optimized. Finally, we focus on pulse sequencing, including pulse-width optimization, DRAG optimization, and randomized benchmarking, to achieve high gate fidelity. We applied this framework to both Transmon and Fluxonium qubits, obtaining results that closely match those found in experimental studies. This work provides a detailed and practical approach to the design, optimization, and calibration of superconducting qubits, contributing to the broader effort to develop scalable quantum computing technologies.