We discuss quantum computers from the perspective of one of their major building blocks, the hardware controller, explaining how it fits into the computer and the requirements and challenges it poses for engineers and scientists.
Quantum computing hardware technologies have advanced during the past two decades, with the goal of building systems that can solve problems that are intractable on classical computers. The ability to realize large-scale systems depends on major advances in materials science, materials engineering, and new fabrication techniques. We identify key materials challenges that currently limit progress in five quantum computing hardware platforms, propose how to tackle these problems, and discuss some new areas for exploration. Addressing these materials challenges will require scientists and engineers to work together to create new, interdisciplinary approaches beyond the current boundaries of the quantum computing field.
This paper introduces superconducting computers. from the perspective of microwave engineering. It provides a system-level overview of cryo-genic quantum hardware and explains how microwave pulses are used to control and read out quantum bits (qubits). Key concepts such as superposition, Bloch sphere representation, and the role of resonators are discussed. The paper also outlines the design of a scalable control system developed at QIQB, Osaka University, including its architecture and synchronization performance. Finally, challenges and future directions toward fault-tolerant quantum computing, including quantum error correction and cryogenic signal multiplexing, are .addressed.
The concept of quantum computing has inspired a whole new generation of scientists, including physicists, engineers, and computer scientists, to fundamentally change the landscape of information technology. With experimental demonstrations stretching back more than two decades, the quantum computing community has achieved a major milestone over the past few years: the ability to build systems that are stretching the limits of what can be classically simulated, and which enable cloud-based research for a wide range of scientists, thus increasing the pool of talent exploring early quantum systems. While such noisy near-term quantum computing systems fall far short of the requirements for fault-tolerant systems, they provide unique test beds for exploring the opportunities for quantum applications. Here, we highlight an IBM-specific perspective of the facets associated with these systems, including quantum software, cloud access, benchmarking quantum systems, error correction and mitigation in such systems, understanding the complexity of quantum circuits, and how early quantum applications can run on near-term quantum computers.