As quantum computation continues to advance, distributed quantum computing is emerging as a crucial configuration, offering a means to leverage the best technology across diverse platforms. This approach is essential for enhancing scalability and advancing quantum resources towards faulttolerant demonstration. A fundamental element of this design is the establishment of scalable quantum networks with robust quantum memory systems. We have recently demonstrated a high efficiency and high bandwidth solid-state quantum memory developed for the Quantum-Accelerated Internet Testbed (QuAInT) at Oak Ridge National Laboratory (ORNL), reaching$28.5 \pm 0.2 \%$efficiency and a 630 MHz absorption window in the material. This work for QuAInT represents a collaborative endeavor across multiple institutions to establish the groundwork for a national quantum internet connection. We will highlight that work here, as well as our strategic vision to build a lower temperature and low-latency quantum memory platform.
As quantum computation continues to advance, distributed quantum computing is emerging as a crucial configuration, offering a means to leverage the best technology across diverse platforms. This approach is essential for enhancing scalability and advancing quantum resources towards faulttolerant demonstration. A fundamental element of this design is the establishment of scalable quantum networks with robust quantum memory systems. We have recently demonstrated a high efficiency and high bandwidth solid-state quantum memory developed for the Quantum-Accelerated Internet Testbed (QuAInT) at Oak Ridge National Laboratory (ORNL), reaching28.5±0.2%efficiency and a 630 MHz absorption window in the material. This work for QuAInT represents a collaborative endeavor across multiple institutions to establish the groundwork for a national quantum internet connection. We will highlight that work here, as well as our strategic vision to build a lower temperature and low-latency quantum memory platform.
The quantum Internet will support paradigm shifts in cybersecurity, distributed quantum computing, and sensing. Its realization, however, has been held back by the lack of practical technologies to enable deployment and scalability. To date, most demonstrations have been limited to laboratories with expensive resources such as cryogenic and vacuum systems. The authors overcome this challenge by designing a field-deployable quantum memory, based on warm atomic vapor, that demonstrates high-fidelity performance and robustness to environmental noise. This represents a key technology for distributing quantum entanglement across large-scale quantum networks.
Over the past decade, quantum computers have emerged as a promising technology to enable transformational advances in information processing and communication and solve problems that are intractable to classical computers. While there is great promise in linking quantum computers together over long distances via quantum channels, these technologies are still under development. Solid-state emitters with coherent spin-photon interfaces, long spin lifetimes, and narrow optical transitions are a leading platform for use as quantum memories in networked quantum repeaters. However, while such emitters have already enabled advanced quantum networking demonstrations in laboratory settings, applying these devices as useful memory devices at scale is a key outstanding challenge. In this thesis, we experimentally investigate solid-state quantum memories for quantum information applications. First, we develop experimental techniques to characterize solid-state emitters with high throughput, enabling both better understanding of the distribution of emitter properties and improved feedback on material preparation and device fabrication. Next, we implement quantum frequency conversion to create a coherent spin-photon interface between silicon-vacancy centers in diamond and optical photons in the low-loss telecom band. Finally, we investigate color centers in other engineering materials, including silicon and silicon carbide, to better understand the fundamental trade space of requirements for solid-state hosts. Together, these efforts represent a significant advance in creating, controlling, and deploying telecom-compatible spin interfaces, paving the way for memory-enabled quantum repeaters.
Building a Quantum Internet requires the development of innovative quantum-enabling networking architectures that integrate advanced communication systems with long-distance quantum communication hardware. Here, we present the implementation of a quantum-enabled internet prototype using a novel physics-centric stack-based quantum network paradigm to govern the dynamics of multiple light-matter Hamiltonians across distant nodes. We demonstrate this concept using a deployed large-scale intercity quantum network connecting laboratories at Stony Brook University and the Brookhaven National Laboratory. This network facilitates a fundamental long-distance quantum network service -that of high-visibility Hong-Ou-Mandel interference of telecom quantum states generated in two independent, telecom-compatible quantum light-matter interfaces separated by a distance of 158 km.
This paper proposes a novel distributed computing accelerator leveraging quantum entanglement for significantly enhanced performance. The core idea is to utilize the instantaneous correlation inherent in entangled quantum states to facilitate rapid data sharing and computation across geographically distant nodes. The system architecture consists of a network of interconnected nodes, each comprising a quantum memory and a quantum processor. Quantum information is encoded into entangled states and transmitted between nodes, bypassing the limitations of classical communication channels. We explore the theoretical potential of this approach to overcome bandwidth bottlenecks and latency issues prevalent in traditional distributed computing, paving the way for ultra-fast distributed computation. The system utilizes entanglement coding techniques for efficient data transmission and proposes a framework for scalable quantum distributed computing. The key contributions lie in the conceptual design of an entanglement-based distributed computing architecture and the exploration of the fundamental advantages offered by quantum correlations. The proposed accelerator addresses critical challenges in high-performance computing, particularly in scenarios demanding rapid data processing across large, distributed systems. Mathematical notation and key formulas are presented throughout to illustrate the core concepts and principles.
Quantum technologies, for example, quantum communication and quantum computation, promise spectacular quantum enhanced advantages beyond what can be done classically. However, quantum states, as the element of quantum technologies, are very fragile and easily get lost to the environment, and meanwhile, their generation and quantum operations are mostly probabilistic. These problems make it exponentially hard to build long-distance quantum channels for quantum communication and large quantum systems for quantum computing. Quantum memory allows quantum states to be stored and retrieved in a programmable fashion, therefore providing an elegant solution to the probabilistic nature and associated limitation by coordinating asynchronous events. In the past decades, enormous advances in quantum memory have been made by developing various storage protocols and their physical implementations, and the quantum memory has gradually evolved from the initial conceptual demonstration to a nearly practical one. Aiming at being practicable for efficient synchronisation and physical scalability, an ideal quantum memory should meet several key features known as high efficiency, low noise level, large time bandwidth product (lifetime divided by pulse duration) and operating at room temperature. Here, we present the research status and development trends of this field by introducing some typical storage protocols. Among these protocols, a room-temperature broadband quantum memory is the most attractive due to its simplicity and practicability. However, at room temperature, noise becomes dominant and is a bottleneck problem that has impeded the realization of a real room-temperature broadband quantum memory in the last decades. Recently, the noise problem has been solved in two memory protocols, i.e. FORD (far off-resonance Duan-Lukin-Cirac-Zoller) protocol and ORCA (off-resonant cascaded absorption) protocol. In this paper, the working principles, the merits and demerits of various quantum memory protocols are illustrated. Furthermore, the approaches to eliminating noise and the applications of quantum memory are summarized.
A distributed quantum network requires versatile and high-fidelity quantum memory nodes, but it remains challenging to make them scalable. This study investigates the use of multiple controllable quantum memories in silicon carbide---an established semiconductor material platform for various quantum technology applications---and provides a viable solution. The authors show that solid-state spins in silicon carbide are ideal quantum memories in a distributed quantum computing network, wherein a controlled generation of highly coherent qubit registers using nuclear spins is possible. This study will impact the future development of quantum networks with solid states spins as quantum memories.