Abstract Quantum memory devices are essential components of integrated quantum-photonic circuits with applications in quantum computing and quantum information processing. The comprehension and quantification of critical properties such as fidelity, coherence time, storage time, and efficiency of quantum memory are insufficient in the extant literature. In this review, we examine the development and characteristics of various types of quantum memories. Although diverse approaches to storing quantum information are described in detail, we emphasize solid-state quantum memory. Furthermore, we discuss the fabrication and characterization of defects of quantum materials, including two-dimensional materials, for quantum memory applications. We survey theoretical tools such as density functional theory for studying defects to evaluate quantum properties.
Abstract Quantum memory devices are essential components of integrated quantum-photonic circuits with applications in quantum computing and quantum information processing. The comprehension and quantification of critical properties such as fidelity, coherence time, storage time, and efficiency of quantum memory are insufficient in the extant literature. In this review, we examine the development and characteristics of various types of quantum memories. Although diverse approaches to storing quantum information are described in detail, we emphasize solid-state quantum memory. Furthermore, we discuss the fabrication and characterization of defects of quantum materials, including two-dimensional materials, for quantum memory applications. We survey theoretical tools such as density functional theory for studying defects to evaluate quantum properties.
Quantum memories, which are devices that store and retrieve fragile quantum states on demand,are central to scalable quantum networks, distributed quantum computing, and advanced quan-tum sensing. The performance, reliability, and scalability of a quantum memory are set, to alarge degree, by the materials from which it is built. This review provides a comparative analy-sis of leading quantum memory platforms, namely superconducting circuits, semiconductor spinqubits, diamond color centers, quantum dots, topological semiconductor and superconductorhybrids, magnon systems, and rare-earth ions in solids, from a materials science point of view.We first set out a compact, materials-level theory that connects host properties to device coher-ence and to the quality of the photon and spin interface. For each platform we then examine theprimary material systems, their intrinsic quantum properties, the state of the art in synthesisand fabrication, and the role of material imperfections such as defects, impurities, and inter-faces in limiting coherence. We analyze material-dependent sensitivity to environmental noise,the challenges of integration with other quantum and classical components, and the emergingmaterials that may overcome present limits. Synthesizing across platforms, we identify recur-ring materials themes. These include the control of defects and interfaces, the need for highpurity and isotopic engineering, and the close coupling between a quantum system and its hostmatrix. We close with a forward view on how materials innovation, supported by computationaldiscovery and advanced characterization, can address the main bottlenecks and bring practicalquantum memories closer.
The approaching era will require computing resources that are future proof across various domains, extending from communications, computing and sensing. It is anticipated that quantum computing will play a major role due to limitations of classical computing. A vital factor in meeting this capability is the need of a non-classical storage unit to facilitate the quantum devices. Therefore, quantum memory becomes a necessity. This paper aims to present detailed discussion on quantum memory, which would begin from fundamental concepts and would range to a more advanced level, with the ultimate goal of identifying the most suitable method for developing quantum applications. The current protocols utilized in quantum memories rely on optically driven and photon echo based techniques. The survey will deeply analyze the processes and principles involved in storing and retrieving information using these methods. It would also assess their key features, including retention time, efficiency, measurement fidelity, bandwidth, and necessary conditions. In addition, the focus would also be on studying the neoteric realms of quantum dots and the Bose Einstein condensates. The paper concludes with challenges in building quantum memories and possible future directions.
Quantum memory, which maps photonic quantum information into a stationary medium and retrieves it at a chosen time, plays a vital role in the advancement of quantum information science. In particular, the scalability of a quantum memory is a central challenge for quantum network that can be overcome by using integrated devices. Quantum memory with an integrated device is highly appealing since it not only expands the number of memories to increase data rates, but also offers seamless compatibility with other on-chip devices and existing fiber network, enabling scalable and convenient applications. Over the past few decades, substantial efforts have been dedicated to achieving integrated quantum memory using rare earth ions doped solid-state materials, color centers, and atomic gases. These physical platforms are the primary candidates for such devices, where remarkable advantages have been demonstrated in achieving high-performance integrated quantum memory, paving the way for efficiently establishing robust and scalable quantum network with integrated quantum devices. In this paper, we aim to provide a comprehensive review of integrated quantum memory, encompassing its background and significance, advancement with bulky memory system, fabrication of integrated device, and its memory function considering various performance metrics. Additionally, we will address the challenges associated with integrated quantum memory and explore its potential applications. By analyzing the current state of the field, this review will make a valuable contribution by offering illustrative examples and providing helpful guidance for future achievements in practical integrated quantum memory.
Quantum information science is entering a second phase, the Quantum Evolution 2.0, in which the challenge has shifted from demonstrating coherent control of individual quantum states to building scalable multi-qubit processors and networks. This transition places materials science at the center of the field. Across superconducting circuits, quantum defects, quantum photonic devices, and emerging materials platforms, including two-dimensional materials and heterostructures, performance is now limited less by device design than by poorly controlled surfaces, buried interfaces, and defects whose atomic identities remain incompletely known. This review surveys the materials challenges of these quantum platforms together with the characterization methods needed to resolve them. For each platform we identify the dominant decoherence mechanisms, the current state of materials understanding, and the most pressing open materials problems. A cross-platform comparison then reveals a shared structure-coherence problem. The implicated material chemistry recurs across platforms, involving light elements in disordered or buried environments, yet no platform can quantitatively connect a specific atomic-scale structure to a measured change in coherence. We close by identifying three needs, mechanistic understanding of decoherence at the atomistic level, high-throughput proxy metrics predictive of device performance, and characterization tools built for quantum materials, whose resolution would advance coherence, scalability, and integration across all platforms.
Abstract An optical quantum memory is a device that can store photonic quantum information and release it after a controlled time. It is an essential component for overcoming channel losses in large‐scale quantum networks. Optical quantum memories have been demonstrated with various physical systems including atomic gases, single atoms in optical cavities, and rare‐earth‐ion doped solids. Now, quantum memories are marching toward miniaturization and integration for large‐scale practical applications. Solid state systems stand as a natural choice due to the physical stability and ease of micro or nano fabrication using well‐established techniques. In the past decade, considerable efforts have been devoted to developing photonic integrated quantum memories, that is, quantum memories based on micro/nano‐photonic structures manufactured in solids. Remarkable performances have been achieved with integrated quantum memories, with the advantages of lower laser/electric power requirements, small volumes, large storage densities, and easy implementations. In this article, the basic concepts of optical quantum memories, the state‐of‐the‐art technologies for fabricating integrated quantum memories in rare‐earth ions doped crystals, and recent advances are introduced, and the roadmap for developing practically useful devices for applications in quantum networks is discussed.
This paper investigates the potential of utilizing quantum memory for quantum information storage. Quantum memory offers a pathway towards robust and scalable quantum computing and communication by providing a means to retain quantum information, a fundamental requirement for any quantum technology. This work explores various mechanisms leveraging quantum effects within specific materials and systems to achieve long-term quantum storage. We examine theoretical frameworks and discuss the challenges and opportunities associated with developing practical quantum memory systems. The core claim is to explore the feasibility of using quantum memory for quantum information storage, focusing on the underlying mechanisms of maintaining quantum coherence. Key areas of investigation include coherence preservation strategies, error correction techniques specifically tailored for quantum memory, and the selection of appropriate materials exhibiting suitable quantum properties for enhanced storage duration. The ultimate goal is to lay the groundwork for future research into constructing stable and reliable quantum memory devices, crucial for realizing the full potential of quantum information processing. ---