Welcome to APL Quantum: From “science is quantum” to “quantum is science and technology”

A very warm welcome to the first issue of APL Quantum!

When the foundations of quantum- or wave-mechanics were established about 100 years ago,¹ this revolutionary new way of thinking built the foundations to develop an understanding and explore the way atoms worked and how these interacted with, for example, light. In addition, without the insight provided by quantum theory, the structure and function of nuclei, materials, and low-temperature phenomena would have largely remained a mystery. While, at present, we are continuing to discover new aspects related to these foundations of quantum theory, quantum science has, facilitated by progress in materials, nanotechnology, and photonics science, progressed from this early scientific upheaval to yet another revolution.

The enormous significance of this second quantum revolution for science, technology, and society is manifest in, for example, the significant investment and activities by today’s industry leaders (such as Microsoft, Google, and IBM), as well as in the prioritization of quantum science and technologies by national quantum strategies and initiatives (e.g., US,² China,³ Europe,⁴ Australia,⁵ or India⁶). Indeed, quantum science and quantum technologies have growing impact on other sciences, such as computation, communication, and encryption technologies, as well as society and the arts. Quantum computers and quantum simulation will advance the discovery of new materials and materials technology as well as artificial intelligence (AI) through the design of quantum networks for AI. Moreover, quantum sensing and quantum metrology have an impact on our fundamental understanding of time (relevant for, e.g., large network synchronization), navigation (more precise GPS), Earth monitoring (gravitational force, Earth’s magnetic field, etc.), medicine (enabling highly precise local and single molecule sensing such as immuno-assay), and data storage (e.g., nano-scale ultra-high density magnetic and quantum storage). Similarly, at a time when secure storage, communication, and privacy are paramount across all spheres, quantum cryptography and quantum communication will contribute to safeguarding the security of personal data (e.g., patient data), secure commerce and banking operations (transfer of information and operations), and national security, including the protection of vital infrastructure (e.g., national grid and water).

With all the spectacular recent progress in the quantum fields, there is, in many of today’s scientific discussions perhaps, a perception that quantum computers and quantum communication systems are well established and, thus, “ready for general use.” Undoubtedly, however, for quantum science and technologies to advance and live up to their full potential, there is still “so much research to be done” and significant scientific and technological breakthroughs to be achieved. In addition, similar scientific and technological progress is required to realize compact and sustainable quantum information technologies. While I am sure that many fundamental quantum discoveries will be made on the way, we certainly should also direct efforts toward rebalancing public perception (social media or recent cinema movie productions nourish a veritable “quantum hype”) of quantum technologies and all opportunities of the whole quantum-ecosystem, particularly for early-career researchers.

It is with our new journal, APL Quantum, that we aim to contribute toward addressing these scientific and technological challenges through an open access journal platform generating links between fundamental quantum research with quantum applications and quantum information science and technologies. APL Quantum seeks to support a broad quantum community, promoting exchange, discussion, and communication of ideas and concepts with insight of and for practical realizations, materials and systems, innovative discoveries, and an active platform for discussion of new fundamental concepts.

Embracing theoretical, simulation, and experimental research, APL Quantum’s scope, as illustrated in Fig. 1, brings together four key areas: Quantum Theory and Fundamentals (e.g., quantum electrodynamics of time-varying gratings,⁷ classification of dissipative quantum chaos through symmetry of open quantum systems,⁸ quantum field simulation to verify the area law of mutual information,⁹ Schrödinger cat states realized in a mechanical oscillator,¹⁰ or a neural network approach to dissipative quantum many-body dynamics¹¹); Quantum Phenomena and Resources (e.g., large-scale integrated quantum graph photonics,¹² detection of a plasmon–polariton quantum wave packet,¹³ near-field generation and control of ultrafast multipartite entanglement for nanoplasmonic quantum networks,¹⁴ ultrafast plexcitonic strong-coupling dynamics at room-temperature,¹⁵ multidimensional entangled structured light,¹⁶ inter-qubit-entanglement mediated by epsilon-near-zero waveguide reservoirs,¹⁷ or electrochemically switchable multimode strong coupling in nanoplasmonic cavities¹⁸); Applied Quantum Science (e.g., quantum simulation for high-energy physics,¹⁹ quantum plasmonic immunoassay sensing,²⁰ long distance multiplexed quantum teleportation from a telecom photon to a solid-state qubit,²¹ or biocompatible surface functionalization architecture for a diamond quantum sensor²²); and Quantum Technologies (e.g., realizing quantum convolutional neural networks on a superconducting quantum processor for recognition of quantum phases,²³ direct implementation of a perceptron in superconducting circuit quantum hardware,²⁴ superconducting quantum simulators based on a photonic-bandgap metamaterial,²⁵ satellite-relayed global quantum communication,²⁶ identification and mitigation of conducting package losses for quantum superconducting devices,²⁷ or nanoscale gap-plasmon-enhanced superconducting single-photon detectors²⁸).

We, the APL Quantum team (Editors and Journal Managers) and all members of our Editorial Advisory Board, are truly excited about this first issue of APL Quantum. This issue presents a first glimpse of the impressive breadth of the quantum field with paper topics ranging from quantum materials (quantum mechanical effects controlling the magnetic properties of transition metal based nanoglass), quantum measurement (quantum-enhanced super-sensitivity of Mach–Zehnder interferometers) as well as establishing and using quantum technologies (correlation-enhanced target detection with entangled photons; ultra-narrowband biphoton frequency combs for high-dimensional quantum information processing and quantum networks; and shallow unitary decompositions of quantum Fredkin and Toffoli gates) to the conception of a programmable photonic quantum emulator for quantum simulation in arbitrary topologies. We are also looking forward to our forthcoming Inaugural Special Issue with, e.g., original manuscripts on quantum emitters in AlN and QED in space–time-varying materials and a Perspective on quantum metaphotonics and, in particular, to interacting actively with you, our authors, and readers, toward supporting a broad and inclusive quantum community. Write to us at aplquantum-journalmanager@aip.org.