ACM TechBrief: Quantum Computing and Simulation

Akira SaiToh, Masahiro Kitagawa

Among initialization schemes for ensemble quantum computation beginning at thermal equilibrium, the scheme proposed by Schulman and Vazirani [in Proceedings of the 31st ACM Symposium on Theory of Computing (STOC'99) (ACM Press, New York, 1999), pp. 322--329] is known for the simple quantum circuit to redistribute the biases (polarizations) of qubits and small time complexity. However, our numerical simulation shows that the number of qubits initialized by the scheme is rather smaller than expected from the von Neumann entropy because of an increase in the sum of the binary entropies of individual qubits, which indicates a growth in the total classical correlation. This result---namely, that there is such a significant growth in the total binary entropy---disagrees with that of their analysis.

Mikio Nakahara

ARTUR K. EKERT, Chiara Macchiavello

Leah Hoffmann

ACM Computing Prize recipient Scott Aaronson discusses his work in quantum complexity.

Travis S. Humble, Mingsheng Ying

Welcome to the inaugural issue of ACM Transactions on Quantum Computing (TQC), a high-impact, peer-reviewed journal that supports the quantum computing community.As the editors-in-chief for TQC, we are delighted to introduce this new journal at a time when quantum computing, and quantum information broadly, are rapidly developing.In recent years, research groups worldwide, as well as both large and small companies, have begun developing quantum computers and computing devices that go beyond the prototype stage toward useful computational tools.The computer science community has already started to understand, evaluate, and build infrastructure around this novel paradigm.Our journal, TQC, is dedicated to providing a central venue for research in this new territory of computer science.The journal aims to publish high-quality papers on both the theory and practice of quantum computing, including but not limited to models of quantum computing, quantum algorithms and complexity, quantum computing architecture, principles and methods of fault-tolerant quantum computation, design automation for quantum computing, issues surrounding compilers for quantum hardware and noisy intermediate-scale quantum implementations, quantum programming languages and systems, distributed quantum computing, quantum networking, quantum security and privacy, and applications (e.g., machine learning and AI) of quantum computing.Quantum computing is interdisciplinary by nature, and the field has been developed from its beginning through the combined effort of researchers from different areas, including computer science, physics, engineering, and mathematics, among many others.We particularly welcome submissions reporting innovative research at the intersection of computer science and these other areas, as well as the application of quantum computing technologies to domains such as quantum simulation, machine learning, and mathematics.We wish to thank the many people who have helped to envision and establish TQC as a highcaliber journal for the quantum community.We are grateful to the members of advisory board for their strong support.We would like to thank our esteemed editorial board members who have joined with enthusiasm in participating in founding this journal.And, of course, we are grateful to the ACM for providing a home for the emerging innovations of quantum computer science.This first issue of TQC presents a collection of five outstanding research papers that capture the breadth and sophistication of quantum computing research.Baker et al. (https://

Osama Babakhel, Mujahid Tabassum, Tripti Sharma