Propagating Gottesman-Kitaev-Preskill states encoded in an optical oscillator

A quantum computer with low-error, high-speed quantum operations and capability for interconnections is required for useful quantum computations. A logical qubit called Gottesman-Kitaev-Preskill (GKP) qubit in a single Bosonic harmonic oscillator is efficient for mitigating errors in a quantum computer. The particularly intriguing prospect of GKP qubits is that entangling gates as well as syndrome measurements for quantum error correction only require efficient, noise-robust linear operations. To date, however, GKP qubits have been only demonstrated at mechanical and microwave frequency in a highly nonlinear physical system. The physical platform that naturally provides the scalable linear toolbox is optics, including near-ideal loss-free beam splitters and near-unit efficiency homodyne detectors that allow to obtain the complete analog syndrome for optimized quantum error correction. Additional optical linear amplifiers and specifically designed GKP qubit states are then all that is needed for universal quantum computing. In this work, we realize a GKP state in propagating light at the telecommunication wavelength and demonstrate homodyne meausurements on the GKP states for the first time without any loss corrections. Our GKP states do not only show non-classicality and non-Gaussianity at room temperature and atmospheric pressure, but unlike the existing schemes with stationary qubits, they are realizable in a propagating wave system. This property permits large-scale quantum computation and interconnections, with strong compatibility to optical fibers and 5G telecommunication technology.Comment: 11 pages, 5 figure

The Virtual Bus: A Network Architecture Designed to Support Modular-Redundant Distributed Periodic Real-Time Control Systems

The Virtual Bus network architecture uses physical layer switching and a combination of space- and time-division multiplexing to link segments of a partial mesh network together on schedule to temporarily form contention-free multi-hop, multi-drop simplex signalling paths, or 'virtual buses'. Network resources are scheduled and routed by a dynamic distributed resource allocation mechanism with self-forming and self-healing characteristics. Multiple virtual buses can coexist simultaneously in a single network, as the resources allocated to each bus are orthogonal in either space or time. The Virtual Bus architecture achieves deterministic delivery times for time-sensitive traffic over multi-hop partial mesh networks by employing true line-speed switching; delays of around 15ns at each switching point are demonstrated experimentally, and further reductions in switching delays are shown to be achievable. Virtual buses are inherently multicast, with delivery skew across multiple destinations proportional to the difference in equivalent physical length to each destination. The Virtual Bus architecture is not a purely theoretical concept; a small research platform has been constructed for development, testing and demonstration purposes

State of the art survey of technologies applicable to NASA's aeronautics, avionics and controls program

The state of the art survey (SOAS) covers six technology areas including flightpath management, aircraft control system, crew station technology, interface & integration technology, military technology, and fundamental technology. The SOAS included contributions from over 70 individuals in industry, government, and the universities

Assessing the Progress of Trapped-Ion Processors Towards Fault-Tolerant Quantum Computation

A quantitative assessment of the progress of small prototype quantum processors towards fault-tolerant quantum computation is a problem of current interest in experimental and theoretical quantum information science. We introduce a necessary and fair criterion for quantum error correction (QEC), which must be achieved in the development of these quantum processors before their sizes are sufficiently big to consider the well-known QEC threshold. We apply this criterion to benchmark the ongoing effort in implementing QEC with topological color codes using trapped-ion quantum processors and, more importantly, to guide the future hardware developments that shall be required in order to demonstrate beneficial QEC with small topological quantum codes. In doing so, we present a thorough description of a realistic trapped-ion toolbox for QEC, and a physically-motivated error model that goes beyond standard simplifications in the QEC literature. We focus on laser-based quantum gates realised in two-species trapped-ion crystals in high-optical aperture segmented traps. Our large-scale numerical analysis shows that, with the foreseen technological improvements hereby described, this platform is a very promising candidate for fault-tolerant quantum computation

LASER Tech Briefs, September 1993

This edition of LASER Tech briefs contains a feature on photonics. The other topics include: Electronic Components and Circuits. Electronic Systems, Physical Sciences, Materials, Computer Programs, Mechanics, Machinery, Fabrication Technology, Mathematics and Information Sciences, Life Sciences and books and reports

Cyber-Physical Systems of Systems: Foundations – A Conceptual Model and Some Derivations: The AMADEOS Legacy

Computer Systems Organization and Communication Networks; Software Engineering; Complex Systems; Information Systems Applications (incl. Internet); Computer Application

Analysis of radiofrequency-based methods for position and velocity determination of autonomous robots in lunar surface exploration missions

The use of distributed systems has been disruptive in almost any industrial sector, from manufacturing to processing plants from environmental monitoring to vehicle control, and many more. It is therefore natural to assess the benefits that such an advantageous engineering paradigm could bring to space exploration. In recent years, we have been witness to the emergence of concepts such as fractionated satellite systems, formation flying, megaconstellations, and femtoswarms. Most of these space missions have evolved from the idea of a decentralization of processes that were formerly performed in platforms conceived as monolithic systems. The application of this concept to robotic systems is not new, and a great deal of scientific contributions on multi-robot systems exists, focusing on different aspects such as cooperative robotics, behavioural or reactive control, distributed artificial intelligence, swarm multi-agent systems etc. The intrinsic advantages of distribution (improved reliability and efficiency, higher robustness, etc.) has been boosted by the exponential growing of computational power density and a simultaneous miniaturization of technology, leading to smaller and more powerful robotic platforms, which could make a distributed robotic system, made of small robotic agents, a powerful substitute to classical large robotic platforms. This thesis proposes, in the framework of multi-robot systems, a localization method for robotic agents in planetary surface exploration scenarios based on RF range and Doppler frequency shift analysis. The relevance of spatial localization awareness in agents belonging to a distributed robotic system is defined in the context of the advantages of robotic exploration. Different range determination techniques and, specifically, the advantages of including Doppler Effect in the determination of the relative position within the robotic system deployed are considered and the strengths and weaknesses analysed accordingly. Special attention is devoted to the noise sources present in the lunar environment, related to a practical (i.e. non-ideal) implementation architecture and its influence on the system performance. From this point of view, we develop a theoretical model for localization accuracy estimation, generated from power spectrum characteristics, in accordance with the system architecture proposed, and consolidated with numerical simulations and a parametrical assessment on a set of real references of components playing a key role in the overall performance. The selected system architecture is then implemented in a representative set-up and tested under laboratory conditions. Algorithms used for carrier frequency generation and frequency measurement are developed, applied and tested in the hardware-on-the-loop breadboard. The results show that Doppler frequency component can be measured with the proposed architecture, yielding a high sensitivity in the determination of relative speed even at standard communication frequencies (UHF), and improving significantly at higher bands (S, C, etc.). This enables the possibility of adding relative speed to relative position determination via sensor fusion techniques, improving the response time and accuracy during navigation through the exploration scenario

Cumulative index to NASA Tech Briefs, 1986-1990, volumes 10-14

Tech Briefs are short announcements of new technology derived from the R&D activities of the National Aeronautics and Space Administration. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This cumulative index of Tech Briefs contains abstracts and four indexes (subject, personal author, originating center, and Tech Brief number) and covers the period 1986 to 1990. The abstract section is organized by the following subject categories: electronic components and circuits, electronic systems, physical sciences, materials, computer programs, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

NASA Tech Briefs, October 1988

Topics include: New Product Ideas; NASA TU Services; Electronic Components and Circuits; Electronic Systems; Physical Sciences Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

Index to 1983 NASA Tech Briefs, volume 8, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1983 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences