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Sample records for advanced quantum communication

  1. Recent advances on integrated quantum communications

    NASA Astrophysics Data System (ADS)

    Orieux, Adeline; Diamanti, Eleni

    2016-08-01

    In recent years, the use of integrated technologies for applications in the field of quantum information processing and communications has made great progress. The resulting devices feature valuable characteristics such as scalability, reproducibility, low cost and interconnectivity, and have the potential to revolutionize our computation and communication practices in the future, much in the way that electronic integrated circuits have drastically transformed our information processing capacities since the last century. Among the multiple applications of integrated quantum technologies, this review will focus on typical components of quantum communication systems and on overall integrated system operation characteristics. We are interested in particular in the use of photonic integration platforms for developing devices necessary in quantum communications, including sources, detectors and both passive and active optical elements. We also illustrate the challenges associated with performing quantum communications on chip, by using the case study of quantum key distribution—the most advanced application of quantum information science. We conclude with promising perspectives in this field.

  2. Quantum Communication

    NASA Astrophysics Data System (ADS)

    Weinfurter, Harald; Zeilinger, Anton

    Quantum entanglement lies at the heart of the new field of quantum communication and computation. For a long time, entanglement was seen just as one of those fancy features which make quantum mechanics so counterintuitive. But recently, quantum information theory has shown the tremendous importance of quantum correlations for the formulation of new methods of information transfer and for algorithms exploiting the capabilities of quantum computers.This chapter describes the first experimental realizations of quantum communication schemes using entangled photon pairs. We show how to make communication secure against eavesdropping using entanglement-based quantum cryptography, how to increase the information capacity of a quantum channel by quantum dense coding and, finally, how to communicate quantum information itself in the process of quantum teleportation.

  3. Practical secure quantum communications

    NASA Astrophysics Data System (ADS)

    Diamanti, Eleni

    2015-05-01

    We review recent advances in the field of quantum cryptography, focusing in particular on practical implementations of two central protocols for quantum network applications, namely key distribution and coin flipping. The former allows two parties to share secret messages with information-theoretic security, even in the presence of a malicious eavesdropper in the communication channel, which is impossible with classical resources alone. The latter enables two distrustful parties to agree on a random bit, again with information-theoretic security, and with a cheating probability lower than the one that can be reached in a classical scenario. Our implementations rely on continuous-variable technology for quantum key distribution and on a plug and play discrete-variable system for coin flipping, and necessitate a rigorous security analysis adapted to the experimental schemes and their imperfections. In both cases, we demonstrate the protocols with provable security over record long distances in optical fibers and assess the performance of our systems as well as their limitations. The reported advances offer a powerful toolbox for practical applications of secure communications within future quantum networks.

  4. Quantum Spread Spectrum Communication

    SciTech Connect

    Humble, Travis S

    2010-01-01

    We demonstrate that spectral teleportation can coherently dilate the spectral probability amplitude of a single photon. In preserving the encoded quantum information, this variant of teleportation subsequently enables a form of quantum spread spectrum communication.

  5. Quantum Spread Spectrum Communication

    SciTech Connect

    Humble, Travis S

    2011-01-01

    We show that communication of single-photon quantum states in a multi-user environment is improved by using spread spectrum communication techniques. We describe a framework for spreading, transmitting, despreading, and detecting single-photon spectral states that mimics conventional spread spectrum techniques. We show in the cases of inadvertent detection, unintentional interference, and multi-user management, that quantum spread spectrum communications may minimize receiver errors by managing quantum channel access.

  6. Network-Centric Quantum Communications

    NASA Astrophysics Data System (ADS)

    Hughes, Richard

    2014-03-01

    Single-photon quantum communications (QC) offers ``future-proof'' cryptographic security rooted in the laws of physics. Today's quantum-secured communications cannot be compromised by unanticipated future technological advances. But to date, QC has only existed in point-to-point instantiations that have limited ability to address the cyber security challenges of our increasingly networked world. In my talk I will describe a fundamentally new paradigm of network-centric quantum communications (NQC) that leverages the network to bring scalable, QC-based security to user groups that may have no direct user-to-user QC connectivity. With QC links only between each of N users and a trusted network node, NQC brings quantum security to N2 user pairs, and to multi-user groups. I will describe a novel integrated photonics quantum smartcard (``QKarD'') and its operation in a multi-node NQC test bed. The QKarDs are used to implement the quantum cryptographic protocols of quantum identification, quantum key distribution and quantum secret splitting. I will explain how these cryptographic primitives are used to provide key management for encryption, authentication, and non-repudiation for user-to-user communications. My talk will conclude with a description of a recent demonstration that QC can meet both the security and quality-of-service (latency) requirements for electric grid control commands and data. These requirements cannot be met simultaneously with present-day cryptography.

  7. Experimental Satellite Quantum Communications.

    PubMed

    Vallone, Giuseppe; Bacco, Davide; Dequal, Daniele; Gaiarin, Simone; Luceri, Vincenza; Bianco, Giuseppe; Villoresi, Paolo

    2015-07-24

    Quantum communication (QC), namely, the faithful transmission of generic quantum states, is a key ingredient of quantum information science. Here we demonstrate QC with polarization encoding from space to ground by exploiting satellite corner cube retroreflectors as quantum transmitters in orbit and the Matera Laser Ranging Observatory of the Italian Space Agency in Matera, Italy, as a quantum receiver. The quantum bit error ratio (QBER) has been kept steadily low to a level suitable for several quantum information protocols, as the violation of Bell inequalities or quantum key distribution (QKD). Indeed, by taking data from different satellites, we demonstrate an average value of QBER=4.6% for a total link duration of 85 s. The mean photon number per pulse μ_{sat} leaving the satellites was estimated to be of the order of one. In addition, we propose a fully operational satellite QKD system by exploiting our communication scheme with orbiting retroreflectors equipped with a modulator, a very compact payload. Our scheme paves the way toward the implementation of a QC worldwide network leveraging existing receivers. PMID:26252672

  8. Experimental Satellite Quantum Communications

    NASA Astrophysics Data System (ADS)

    Vallone, Giuseppe; Bacco, Davide; Dequal, Daniele; Gaiarin, Simone; Luceri, Vincenza; Bianco, Giuseppe; Villoresi, Paolo

    2015-07-01

    Quantum communication (QC), namely, the faithful transmission of generic quantum states, is a key ingredient of quantum information science. Here we demonstrate QC with polarization encoding from space to ground by exploiting satellite corner cube retroreflectors as quantum transmitters in orbit and the Matera Laser Ranging Observatory of the Italian Space Agency in Matera, Italy, as a quantum receiver. The quantum bit error ratio (QBER) has been kept steadily low to a level suitable for several quantum information protocols, as the violation of Bell inequalities or quantum key distribution (QKD). Indeed, by taking data from different satellites, we demonstrate an average value of QBER =4.6 % for a total link duration of 85 s. The mean photon number per pulse μsat leaving the satellites was estimated to be of the order of one. In addition, we propose a fully operational satellite QKD system by exploiting our communication scheme with orbiting retroreflectors equipped with a modulator, a very compact payload. Our scheme paves the way toward the implementation of a QC worldwide network leveraging existing receivers.

  9. Experimental Satellite Quantum Communications.

    PubMed

    Vallone, Giuseppe; Bacco, Davide; Dequal, Daniele; Gaiarin, Simone; Luceri, Vincenza; Bianco, Giuseppe; Villoresi, Paolo

    2015-07-24

    Quantum communication (QC), namely, the faithful transmission of generic quantum states, is a key ingredient of quantum information science. Here we demonstrate QC with polarization encoding from space to ground by exploiting satellite corner cube retroreflectors as quantum transmitters in orbit and the Matera Laser Ranging Observatory of the Italian Space Agency in Matera, Italy, as a quantum receiver. The quantum bit error ratio (QBER) has been kept steadily low to a level suitable for several quantum information protocols, as the violation of Bell inequalities or quantum key distribution (QKD). Indeed, by taking data from different satellites, we demonstrate an average value of QBER=4.6% for a total link duration of 85 s. The mean photon number per pulse μ_{sat} leaving the satellites was estimated to be of the order of one. In addition, we propose a fully operational satellite QKD system by exploiting our communication scheme with orbiting retroreflectors equipped with a modulator, a very compact payload. Our scheme paves the way toward the implementation of a QC worldwide network leveraging existing receivers.

  10. Quantum entanglement, quantum communication and the limits of quantum computing

    NASA Astrophysics Data System (ADS)

    Ambainis, Andris

    Quantum entanglement is a term describing the quantum correlations between different parts of a quantum system. Quantum information theory has developed sophisticated techniques to quantify and study quantum entanglement. In this thesis, we show how to apply those techniques to problems in quantum algorithms, complexity theory, communication and cryptography. The main results are: (1) quantum communication protocols that are exponentially more efficient that conventional (classical) communication protocols, (2) unconditionally secure quantum protocols for cryptographic problems, (3) a new "quantum adversary" method for proving lower bounds on quantum algorithms, (4) a study of "one clean qubit computation", a model related to the experimental implementation of quantum computers using NMR (nucleo-magnetic resonance) technology.

  11. Up-conversion detectors at 1550 nm for quantum communication: review and recent advances

    NASA Astrophysics Data System (ADS)

    Tournier, M.; Alibart, O.; Doutre, F.; Tascu, S.; de Micheli, M. P.; Ostrowsky, D. B.; Thyagarajan, K.; Tanzilli, S.

    Up-conversion, or hybrid, detectors have been investigated in quantum communication experiments to replace Indium-Gallium-Arsenide avalanche photodiodes (InGaAs-APD) for the detection of infrared and telecom single photons. Those detectors are based on the supposedly noise-free process of frequency up-conversion, also called sum-frequency generation (SFG), using a second order (χ^2) non-linear crystal. Powered by an intense pump laser, this process permits transposing with a certain probability the single photons at telecom wavelengths to the visible range where silicon APDs (Si-APD) operate with a much better performance than InGaAs detectors. To date, the literature reports up-conversion detectors having efficiency and noise figures comparable to that of the best commercially available IngaAs-APDs. However, in all of these previous realizations, a pump-induced noise is always observed which was initially expected to be as low as the dark count level of the Si-APDs. Although this additional noise represents a problem for the detection, up-conversion detectors have advantageously replaced InGaAs-APDs in various long-distance quantum cryptography schemes since they offer a continuous regime operation mode instead of a gated mode necessary for InGaAs-APDs, and the possibility of much higher counting rates. Despite attempted explanations, no detailed nor conclusive study of this noise has been reported. The aim of this paper is to offer a definitive explanation for this noise. We first give a review of the state of the art by describing already demonstrated up-conversion detectors. We discuss these realizations especially regarding the choices made for the material, in bulk or guided configurations, the single photon wavelengths, and the pump scheme. Then we describe an original device made of waveguides integrated on periodically poled lithium niobate (PPLN)or on single-domain lithium niobate aimed at investigating the origin of the additional pump-induced noise

  12. Advanced quantum noise correlations

    NASA Astrophysics Data System (ADS)

    Vogl, Ulrich; Glasser, Ryan T.; Clark, Jeremy B.; Glorieux, Quentin; Li, Tian; Corzo, Neil V.; Lett, Paul D.

    2014-01-01

    We use the quantum correlations of twin beams of light to investigate the fundamental addition of noise when one of the beams propagates through a fast-light medium based on phase-insensitive gain. The experiment is based on two successive four-wave mixing processes in rubidium vapor, which allow for the generation of bright two-mode-squeezed twin beams followed by a controlled advancement while maintaining the shared quantum correlations between the beams. The demonstrated effect allows the study of irreversible decoherence in a medium exhibiting anomalous dispersion, and for the first time shows the advancement of a bright nonclassical state of light. The advancement and corresponding degradation of the quantum correlations are found to be operating near the fundamental quantum limit imposed by using a phase-insensitive amplifier.

  13. Multiuser quantum communication networks

    SciTech Connect

    Wojcik, Antoni; Kurzynski, Pawel; Grudka, Andrzej; Luczak, Tomasz; Gdala, Tomasz; Bednarska, Malgorzata

    2007-02-15

    We study a quantum state transfer between spins interacting with an arbitrary network of spins coupled by uniform XX interactions. It is shown that in such a system under fairly general conditions, we can expect a nearly perfect transfer of states. Then we analyze a generalization of this model to the case of many network users, where the sender can choose which party he wants to communicate with by appropriately tuning his local magnetic field. We also remark that a similar idea can be used to create an entanglement between several spins coupled to the network.

  14. Advanced Communication Processing Techniques

    NASA Astrophysics Data System (ADS)

    Scholtz, Robert A.

    This document contains the proceedings of the workshop Advanced Communication Processing Techniques, held May 14 to 17, 1989, near Ruidoso, New Mexico. Sponsored by the Army Research Office (under Contract DAAL03-89-G-0016) and organized by the Communication Sciences Institute of the University of Southern California, the workshop had as its objective to determine those applications of intelligent/adaptive communication signal processing that have been realized and to define areas of future research. We at the Communication Sciences Institute believe that there are two emerging areas which deserve considerably more study in the near future: (1) Modulation characterization, i.e., the automation of modulation format recognition so that a receiver can reliably demodulate a signal without using a priori information concerning the signal's structure, and (2) the incorporation of adaptive coding into communication links and networks. (Encoders and decoders which can operate with a wide variety of codes exist, but the way to utilize and control them in links and networks is an issue). To support these two new interest areas, one must have both a knowledge of (3) the kinds of channels and environments in which the systems must operate, and of (4) the latest adaptive equalization techniques which might be employed in these efforts.

  15. Quantum secret sharing with minimized quantum communication

    NASA Astrophysics Data System (ADS)

    Fortescue, Ben; Gour, Gilad

    2013-03-01

    Standard techniques for sharing a quantum secret among multiple players (such that certain subsets of the players can recover the secret while others are denied all knowledge of the secret) require a large amount of quantum communication to distribute the secret, which is likely to be the most costly resource in any practical scheme. Two known methods for reducing this cost are the use of imperfect ``ramp'' secret sharing (in which security is sacrificed for efficiency) and classical encryption (in which certain elements of the players' shares consist of classical information only). We demonstrate how one may combine these methods to reduce the required quantum communication below what has been previously achieved, in some cases to a provable minimum, without any loss of security. The techniques involved are closely-related to the properties of stabilizer codes, and thus have strong potential for being adapted to a wide range of quantum secret sharing schemes.

  16. Reliable quantum communication over a quantum relay channel

    SciTech Connect

    Gyongyosi, Laszlo; Imre, Sandor

    2014-12-04

    We show that reliable quantum communication over an unreliable quantum relay channels is possible. The coding scheme combines the results on the superadditivity of quantum channels and the efficient quantum coding approaches.

  17. High speed quantum communication testbed

    NASA Astrophysics Data System (ADS)

    Williams, Carl J.; Tang, Xiao; Heikkero, Mikko; Rouzaud, Julie; Lu, Richang; Goedecke, Andreas; Migdall, Alan L.; Mink, Alan; Nakassis, Anastase; Pibida, Leticia S.; Wen, Jesse; Hagley, Edward; Clark, Charles W.

    2002-12-01

    We describe the status of the NIST Quantum Communication Testbed (QCT) facility. QCT is a facility for exploring quantum communication in an environment similar to that projected for early commercial implementations: quantum cryptographic key exchange on a gigabit/second free-space optical (FSO) channel. Its purpose is to provide an open platform for testing and validating performance in the application, network, and physical layers of quantum communications systems. The channel uses modified commercial FSO equipment to link two buildings on the Gaithersburg, MD campus of the National Institute of Standards and Technology (NIST), separated by approximately 600 meters. At the time of writing, QCT is under construction; it will eventually be made available to the research community as a user facility. This paper presents the basic design considerations underlying QCT, and reports the status of the project.

  18. Advanced satellite communication system

    NASA Technical Reports Server (NTRS)

    Staples, Edward J.; Lie, Sen

    1992-01-01

    The objective of this research program was to develop an innovative advanced satellite receiver/demodulator utilizing surface acoustic wave (SAW) chirp transform processor and coherent BPSK demodulation. The algorithm of this SAW chirp Fourier transformer is of the Convolve - Multiply - Convolve (CMC) type, utilizing off-the-shelf reflective array compressor (RAC) chirp filters. This satellite receiver, if fully developed, was intended to be used as an on-board multichannel communications repeater. The Advanced Communications Receiver consists of four units: (1) CMC processor, (2) single sideband modulator, (3) demodulator, and (4) chirp waveform generator and individual channel processors. The input signal is composed of multiple user transmission frequencies operating independently from remotely located ground terminals. This signal is Fourier transformed by the CMC Processor into a unique time slot for each user frequency. The CMC processor is driven by a waveform generator through a single sideband (SSB) modulator. The output of the coherent demodulator is composed of positive and negative pulses, which are the envelopes of the chirp transform processor output. These pulses correspond to the data symbols. Following the demodulator, a logic circuit reconstructs the pulses into data, which are subsequently differentially decoded to form the transmitted data. The coherent demodulation and detection of BPSK signals derived from a CMC chirp transform processor were experimentally demonstrated and bit error rate (BER) testing was performed. To assess the feasibility of such advanced receiver, the results were compared with the theoretical analysis and plotted for an average BER as a function of signal-to-noise ratio. Another goal of this SBIR program was the development of a commercial product. The commercial product developed was an arbitrary waveform generator. The successful sales have begun with the delivery of the first arbitrary waveform generator.

  19. Quantum communication and information processing

    NASA Astrophysics Data System (ADS)

    Beals, Travis Roland

    Quantum computers enable dramatically more efficient algorithms for solving certain classes of computational problems, but, in doing so, they create new problems. In particular, Shor's Algorithm allows for efficient cryptanalysis of many public-key cryptosystems. As public key cryptography is a critical component of present-day electronic commerce, it is crucial that a working, secure replacement be found. Quantum key distribution (QKD), first developed by C.H. Bennett and G. Brassard, offers a partial solution, but many challenges remain, both in terms of hardware limitations and in designing cryptographic protocols for a viable large-scale quantum communication infrastructure. In Part I, I investigate optical lattice-based approaches to quantum information processing. I look at details of a proposal for an optical lattice-based quantum computer, which could potentially be used for both quantum communications and for more sophisticated quantum information processing. In Part III, I propose a method for converting and storing photonic quantum bits in the internal state of periodically-spaced neutral atoms by generating and manipulating a photonic band gap and associated defect states. In Part II, I present a cryptographic protocol which allows for the extension of present-day QKD networks over much longer distances without the development of new hardware. I also present a second, related protocol which effectively solves the authentication problem faced by a large QKD network, thus making QKD a viable, information-theoretic secure replacement for public key cryptosystems.

  20. Distributed wireless quantum communication networks

    NASA Astrophysics Data System (ADS)

    Yu, Xu-Tao; Xu, Jin; Zhang, Zai-Chen

    2013-09-01

    The distributed wireless quantum communication network (DWQCN) has a distributed network topology and transmits information by quantum states. In this paper, we present the concept of the DWQCN and propose a system scheme to transfer quantum states in the DWQCN. The system scheme for transmitting information between any two nodes in the DWQCN includes a routing protocol and a scheme for transferring quantum states. The routing protocol is on-demand and the routing metric is selected based on the number of entangled particle pairs. After setting up a route, quantum teleportation and entanglement swapping are used for transferring quantum states. Entanglement swapping is achieved along with the process of routing set up and the acknowledgment packet transmission. The measurement results of each entanglement swapping are piggybacked with route reply packets or acknowledgment packets. After entanglement swapping, a direct quantum link between source and destination is set up and quantum states are transferred by quantum teleportation. Adopting this scheme, the measurement results of entanglement swapping do not need to be transmitted specially, which decreases the wireless transmission cost and transmission delay.

  1. Secure communications using quantum cryptography

    SciTech Connect

    Hughes, R.J.; Buttler, W.T.; Kwiat, P.G.

    1997-08-01

    The secure distribution of the secret random bit sequences known as {open_quotes}key{close_quotes} material, is an essential precursor to their use for the encryption and decryption of confidential communications. Quantum cryptography is an emerging technology for secure key distribution with single-photon transmissions, nor evade detection (eavesdropping raises the key error rate above a threshold value). We have developed experimental quantum cryptography systems based on the transmission of non-orthogonal single-photon states to generate shared key material over multi-kilometer optical fiber paths and over line-of-sight links. In both cases, key material is built up using the transmission of a single-photon per bit of an initial secret random sequence. A quantum-mechanically random subset of this sequence is identified, becoming the key material after a data reconciliation stage with the sender. In our optical fiber experiment we have performed quantum key distribution over 24-km of underground optical fiber using single-photon interference states, demonstrating that secure, real-time key generation over {open_quotes}open{close_quotes} multi-km node-to-node optical fiber communications links is possible. We have also constructed a quantum key distribution system for free-space, line-of-sight transmission using single-photon polarization states, which is currently undergoing laboratory testing. 7 figs.

  2. Industrial application for global quantum communication

    NASA Astrophysics Data System (ADS)

    Mirza, A.; Petruccione, F.

    2012-09-01

    In the last decade the quantum communication community has witnessed great advances in photonic quantum cryptography technology with the research, development and commercialization of automated Quantum Key Distribution (QKD) devices. These first generation devices are however bottlenecked by the achievable spatial coverage. This is due to the intrinsic absorption of the quantum particle into the communication medium. As QKD is of paramount importance in the future ICT landscape, various innovative solutions have been developed and tested to expand the spatial coverage of these networks such as the Quantum City initiative in Durban, South Africa. To expand this further into a global QKD-secured network, recent efforts have focussed on high-altitude free-space techniques through the use of satellites. This couples the QKD-secured Metropolitan Area Networks (MANs) with secured ground-tosatellite links as access points to a global network. Such a solution, however, has critical limitations that reduce its commercial feasibility. As parallel step to the development of satellitebased global QKD networks, we investigate the use of the commercial aircrafts' network as secure transport mechanisms in a global QKD network. This QKD-secured global network will provide a robust infrastructure to create, distribute and manage encryption keys between the MANs of the participating cities.

  3. Quantum authencryption: one-step authenticated quantum secure direct communications for off-line communicants

    NASA Astrophysics Data System (ADS)

    Hwang, Tzonelih; Luo, Yi-Ping; Yang, Chun-Wei; Lin, Tzu-Han

    2014-04-01

    This work proposes a new direction in quantum cryptography called quantum authencryption. Quantum authencryption (QA), a new term to distinguish from authenticated quantum secure direct communications, is used to describe the technique of combining quantum encryption and quantum authentication into one process for off-line communicants. QA provides a new way of quantum communications without the presence of a receiver on line, and thus makes many applications depending on secure one-way quantum communications, such as quantum E-mail systems, possible. An example protocol using single photons and one-way hash functions is presented to realize the requirements on QA.

  4. Satellite-Based Quantum Communications

    SciTech Connect

    Hughes, Richard J; Nordholt, Jane E; McCabe, Kevin P; Newell, Raymond T; Peterson, Charles G

    2010-09-20

    Single-photon quantum communications (QC) offers the attractive feature of 'future proof', forward security rooted in the laws of quantum physics. Ground based quantum key distribution (QKD) experiments in optical fiber have attained transmission ranges in excess of 200km, but for larger distances we proposed a methodology for satellite-based QC. Over the past decade we have devised solutions to the technical challenges to satellite-to-ground QC, and we now have a clear concept for how space-based QC could be performed and potentially utilized within a trusted QKD network architecture. Functioning as a trusted QKD node, a QC satellite ('QC-sat') could deliver secret keys to the key stores of ground-based trusted QKD network nodes, to each of which multiple users are connected by optical fiber or free-space QC. A QC-sat could thereby extend quantum-secured connectivity to geographically disjoint domains, separated by continental or inter-continental distances. In this paper we describe our system concept that makes QC feasible with low-earth orbit (LEO) QC-sats (200-km-2,000-km altitude orbits), and the results of link modeling of expected performance. Using the architecture that we have developed, LEO satellite-to-ground QKD will be feasible with secret bit yields of several hundred 256-bit AES keys per contact. With multiple ground sites separated by {approx} 100km, mitigation of cloudiness over any single ground site would be possible, potentially allowing multiple contact opportunities each day. The essential next step is an experimental QC-sat. A number of LEO-platforms would be suitable, ranging from a dedicated, three-axis stabilized small satellite, to a secondary experiment on an imaging satellite. to the ISS. With one or more QC-sats, low-latency quantum-secured communications could then be provided to ground-based users on a global scale. Air-to-ground QC would also be possible.

  5. Noisy quantum phase communication channels

    NASA Astrophysics Data System (ADS)

    Teklu, Berihu; Trapani, Jacopo; Olivares, Stefano; Paris, Matteo G. A.

    2015-06-01

    We address quantum phase channels, i.e communication schemes where information is encoded in the phase-shift imposed to a given signal, and analyze their performances in the presence of phase diffusion. We evaluate mutual information for coherent and phase-coherent signals, and for both ideal and realistic phase receivers. We show that coherent signals offer better performances than phase-coherent ones, and that realistic phase channels are effective ones in the relevant regime of low energy and large alphabets.

  6. Metrology for industrial quantum communications: the MIQC project

    NASA Astrophysics Data System (ADS)

    Rastello, M. L.; Degiovanni, I. P.; Sinclair, A. G.; Kück, S.; Chunnilall, C. J.; Porrovecchio, G.; Smid, M.; Manoocheri, F.; Ikonen, E.; Kubarsepp, T.; Stucki, D.; Hong, K. S.; Kim, S. K.; Tosi, A.; Brida, G.; Meda, A.; Piacentini, F.; Traina, P.; Natsheh, A. Al; Cheung, J. Y.; Müller, I.; Klein, R.; Vaigu, A.

    2014-12-01

    The ‘Metrology for Industrial Quantum Communication Technologies’ project (MIQC) is a metrology framework that fosters development and market take-up of quantum communication technologies and is aimed at achieving maximum impact for the European industry in this area. MIQC is focused on quantum key distribution (QKD) technologies, the most advanced quantum-based technology towards practical application. QKD is a way of sending cryptographic keys with absolute security. It does this by exploiting the ability to encode in a photon's degree of freedom specific quantum states that are noticeably disturbed if an eavesdropper trying to decode it is present in the communication channel. The MIQC project has started the development of independent measurement standards and definitions for the optical components of QKD system, since one of the perceived barriers to QKD market success is the lack of standardization and quality assurance.

  7. Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Gedney, Richard T.; Schertler, Ronald J.

    1989-01-01

    The NASA Advanced Communications Technology Satellite (ACTS) was conceived to help maintain U.S. leadership in the world's communications-satellite market. This experimental satellite is expected to be launched by NASA in 1992 and to furnish the technology necessary for establishing very small aperture terminal digital networks which provide on-demand full-mesh connectivity, and 1.544-MBPS services with only a single hop. Utilizing on-board switching and processing, each individual voice or data circuit can be separately routed to any location in the network. This paper provides an overview of the ACTS and discusses the value of the technology for future communications systems.

  8. Software-defined Quantum Communication Systems

    SciTech Connect

    Humble, Travis S; Sadlier, Ronald J

    2013-01-01

    We show how to extend the paradigm of software-defined communication to include quantum communication systems. We introduce the decomposition of a quantum communication terminal into layers separating the concerns of the hardware, software, and middleware. We provide detailed descriptions of how each component operates and we include results of an implementation of the super-dense coding protocol. We argue that the versatility of software-defined quantum communication test beds can be useful for exploring new regimes in communication and rapidly prototyping new systems.

  9. Authenticated semi-quantum direct communication protocols using Bell states

    NASA Astrophysics Data System (ADS)

    Luo, Yi-Ping; Hwang, Tzonelih

    2016-02-01

    This study presents the first two authenticated semi-quantum direct communication protocols without using any classical channel. By pre-sharing a master secret key between two communicants, a sender with advanced quantum devices can transmit a secret message to a receiver who can only perform classical operations without any information leakage. The receiver is then capable of verifying the message up to the single-qubit level, i.e., a one-qubit modification of the transmitted quantum sequence can be detected with a probability close to 1. Moreover, the proposed protocols are resistant to several well-known attacks.

  10. PREFACE: Quantum Information, Communication, Computation and Cryptography

    NASA Astrophysics Data System (ADS)

    Benatti, F.; Fannes, M.; Floreanini, R.; Petritis, D.

    2007-07-01

    The application of quantum mechanics to information related fields such as communication, computation and cryptography is a fast growing line of research that has been witnessing an outburst of theoretical and experimental results, with possible practical applications. On the one hand, quantum cryptography with its impact on secrecy of transmission is having its first important actual implementations; on the other hand, the recent advances in quantum optics, ion trapping, BEC manipulation, spin and quantum dot technologies allow us to put to direct test a great deal of theoretical ideas and results. These achievements have stimulated a reborn interest in various aspects of quantum mechanics, creating a unique interplay between physics, both theoretical and experimental, mathematics, information theory and computer science. In view of all these developments, it appeared timely to organize a meeting where graduate students and young researchers could be exposed to the fundamentals of the theory, while senior experts could exchange their latest results. The activity was structured as a school followed by a workshop, and took place at The Abdus Salam International Center for Theoretical Physics (ICTP) and The International School for Advanced Studies (SISSA) in Trieste, Italy, from 12-23 June 2006. The meeting was part of the activity of the Joint European Master Curriculum Development Programme in Quantum Information, Communication, Cryptography and Computation, involving the Universities of Cergy-Pontoise (France), Chania (Greece), Leuven (Belgium), Rennes1 (France) and Trieste (Italy). This special issue of Journal of Physics A: Mathematical and Theoretical collects 22 contributions from well known experts who took part in the workshop. They summarize the present day status of the research in the manifold aspects of quantum information. The issue is opened by two review articles, the first by G Adesso and F Illuminati discussing entanglement in continuous variable

  11. Optimal architectures for long distance quantum communication.

    PubMed

    Muralidharan, Sreraman; Li, Linshu; Kim, Jungsang; Lütkenhaus, Norbert; Lukin, Mikhail D; Jiang, Liang

    2016-01-01

    Despite the tremendous progress of quantum cryptography, efficient quantum communication over long distances (≥ 1000 km) remains an outstanding challenge due to fiber attenuation and operation errors accumulated over the entire communication distance. Quantum repeaters (QRs), as a promising approach, can overcome both photon loss and operation errors, and hence significantly speedup the communication rate. Depending on the methods used to correct loss and operation errors, all the proposed QR schemes can be classified into three categories (generations). Here we present the first systematic comparison of three generations of quantum repeaters by evaluating the cost of both temporal and physical resources, and identify the optimized quantum repeater architecture for a given set of experimental parameters for use in quantum key distribution. Our work provides a roadmap for the experimental realizations of highly efficient quantum networks over transcontinental distances. PMID:26876670

  12. Optimal architectures for long distance quantum communication

    PubMed Central

    Muralidharan, Sreraman; Li, Linshu; Kim, Jungsang; Lütkenhaus, Norbert; Lukin, Mikhail D.; Jiang, Liang

    2016-01-01

    Despite the tremendous progress of quantum cryptography, efficient quantum communication over long distances (≥1000 km) remains an outstanding challenge due to fiber attenuation and operation errors accumulated over the entire communication distance. Quantum repeaters (QRs), as a promising approach, can overcome both photon loss and operation errors, and hence significantly speedup the communication rate. Depending on the methods used to correct loss and operation errors, all the proposed QR schemes can be classified into three categories (generations). Here we present the first systematic comparison of three generations of quantum repeaters by evaluating the cost of both temporal and physical resources, and identify the optimized quantum repeater architecture for a given set of experimental parameters for use in quantum key distribution. Our work provides a roadmap for the experimental realizations of highly efficient quantum networks over transcontinental distances. PMID:26876670

  13. Optimal architectures for long distance quantum communication

    NASA Astrophysics Data System (ADS)

    Muralidharan, Sreraman; Li, Linshu; Kim, Jungsang; Lütkenhaus, Norbert; Lukin, Mikhail D.; Jiang, Liang

    2016-02-01

    Despite the tremendous progress of quantum cryptography, efficient quantum communication over long distances (≥1000 km) remains an outstanding challenge due to fiber attenuation and operation errors accumulated over the entire communication distance. Quantum repeaters (QRs), as a promising approach, can overcome both photon loss and operation errors, and hence significantly speedup the communication rate. Depending on the methods used to correct loss and operation errors, all the proposed QR schemes can be classified into three categories (generations). Here we present the first systematic comparison of three generations of quantum repeaters by evaluating the cost of both temporal and physical resources, and identify the optimized quantum repeater architecture for a given set of experimental parameters for use in quantum key distribution. Our work provides a roadmap for the experimental realizations of highly efficient quantum networks over transcontinental distances.

  14. Optimal architectures for long distance quantum communication.

    PubMed

    Muralidharan, Sreraman; Li, Linshu; Kim, Jungsang; Lütkenhaus, Norbert; Lukin, Mikhail D; Jiang, Liang

    2016-02-15

    Despite the tremendous progress of quantum cryptography, efficient quantum communication over long distances (≥ 1000 km) remains an outstanding challenge due to fiber attenuation and operation errors accumulated over the entire communication distance. Quantum repeaters (QRs), as a promising approach, can overcome both photon loss and operation errors, and hence significantly speedup the communication rate. Depending on the methods used to correct loss and operation errors, all the proposed QR schemes can be classified into three categories (generations). Here we present the first systematic comparison of three generations of quantum repeaters by evaluating the cost of both temporal and physical resources, and identify the optimized quantum repeater architecture for a given set of experimental parameters for use in quantum key distribution. Our work provides a roadmap for the experimental realizations of highly efficient quantum networks over transcontinental distances.

  15. Secure quantum communication using classical correlated channel

    NASA Astrophysics Data System (ADS)

    Costa, D.; de Almeida, N. G.; Villas-Boas, C. J.

    2016-07-01

    We propose a secure protocol to send quantum information from one part to another without a quantum channel. In our protocol, which resembles quantum teleportation, a sender (Alice) and a receiver (Bob) share classical correlated states instead of EPR ones, with Alice performing measurements in two different bases and then communicating her results to Bob through a classical channel. Our secure quantum communication protocol requires the same amount of classical bits as the standard quantum teleportation protocol. In our scheme, as in the usual quantum teleportation protocol, once the classical channel is established in a secure way, a spy (Eve) will never be able to recover the information of the unknown quantum state, even if she is aware of Alice's measurement results. Security, advantages, and limitations of our protocol are discussed and compared with the standard quantum teleportation protocol.

  16. Secure quantum communication using classical correlated channel

    NASA Astrophysics Data System (ADS)

    Costa, D.; de Almeida, N. G.; Villas-Boas, C. J.

    2016-10-01

    We propose a secure protocol to send quantum information from one part to another without a quantum channel. In our protocol, which resembles quantum teleportation, a sender (Alice) and a receiver (Bob) share classical correlated states instead of EPR ones, with Alice performing measurements in two different bases and then communicating her results to Bob through a classical channel. Our secure quantum communication protocol requires the same amount of classical bits as the standard quantum teleportation protocol. In our scheme, as in the usual quantum teleportation protocol, once the classical channel is established in a secure way, a spy (Eve) will never be able to recover the information of the unknown quantum state, even if she is aware of Alice's measurement results. Security, advantages, and limitations of our protocol are discussed and compared with the standard quantum teleportation protocol.

  17. Recent progress of quantum communication in China (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Zhang, Qiang

    2016-04-01

    Quantum communication, based on the quantum physics, can provide information theoretical security. Building a global quantum network is one ultimate goal for the research of quantum information. Here, this talk will review the progress for quantum communication in China, including quantum key distribution over metropolitan area with untrustful relay, field test of quantum entanglement swapping over metropolitan network, the 2000 km quantum key distribution main trunk line, and satellite based quantum communication.

  18. Multiparty-controlled quantum secure direct communication

    SciTech Connect

    Xiu, X.-M. Dong, L.; Gao, Y.-J.; Chi, F.

    2007-12-15

    A theoretical scheme of a multiparty-controlled quantum secure direct communication is proposed. The supervisor prepares a communication network with Einstein-Podolsky-Rosen pairs and auxiliary particles. After passing a security test of the communication network, a supervisor tells the users the network is secure and they can communicate. If the controllers allow the communicators to communicate, the controllers should perform measurements and inform the communicators of the outcomes. The communicators then begin to communicate after they perform a security test of the quantum channel and verify that it is secure. The recipient can decrypt the secret message in a classical message from the sender depending on the protocol. Any two users in the network can communicate through the above processes under the control of the supervisor and the controllers.

  19. Quantum memories: emerging applications and recent advances

    PubMed Central

    Heshami, Khabat; England, Duncan G.; Humphreys, Peter C.; Bustard, Philip J.; Acosta, Victor M.; Nunn, Joshua; Sussman, Benjamin J.

    2016-01-01

    Quantum light–matter interfaces are at the heart of photonic quantum technologies. Quantum memories for photons, where non-classical states of photons are mapped onto stationary matter states and preserved for subsequent retrieval, are technical realizations enabled by exquisite control over interactions between light and matter. The ability of quantum memories to synchronize probabilistic events makes them a key component in quantum repeaters and quantum computation based on linear optics. This critical feature has motivated many groups to dedicate theoretical and experimental research to develop quantum memory devices. In recent years, exciting new applications, and more advanced developments of quantum memories, have proliferated. In this review, we outline some of the emerging applications of quantum memories in optical signal processing, quantum computation and non-linear optics. We review recent experimental and theoretical developments, and their impacts on more advanced photonic quantum technologies based on quantum memories.

  20. Quantum memories: emerging applications and recent advances

    NASA Astrophysics Data System (ADS)

    Heshami, Khabat; England, Duncan G.; Humphreys, Peter C.; Bustard, Philip J.; Acosta, Victor M.; Nunn, Joshua; Sussman, Benjamin J.

    2016-11-01

    Quantum light-matter interfaces are at the heart of photonic quantum technologies. Quantum memories for photons, where non-classical states of photons are mapped onto stationary matter states and preserved for subsequent retrieval, are technical realizations enabled by exquisite control over interactions between light and matter. The ability of quantum memories to synchronize probabilistic events makes them a key component in quantum repeaters and quantum computation based on linear optics. This critical feature has motivated many groups to dedicate theoretical and experimental research to develop quantum memory devices. In recent years, exciting new applications, and more advanced developments of quantum memories, have proliferated. In this review, we outline some of the emerging applications of quantum memories in optical signal processing, quantum computation and non-linear optics. We review recent experimental and theoretical developments, and their impacts on more advanced photonic quantum technologies based on quantum memories.

  1. Quantum memories: emerging applications and recent advances

    PubMed Central

    Heshami, Khabat; England, Duncan G.; Humphreys, Peter C.; Bustard, Philip J.; Acosta, Victor M.; Nunn, Joshua; Sussman, Benjamin J.

    2016-01-01

    Quantum light–matter interfaces are at the heart of photonic quantum technologies. Quantum memories for photons, where non-classical states of photons are mapped onto stationary matter states and preserved for subsequent retrieval, are technical realizations enabled by exquisite control over interactions between light and matter. The ability of quantum memories to synchronize probabilistic events makes them a key component in quantum repeaters and quantum computation based on linear optics. This critical feature has motivated many groups to dedicate theoretical and experimental research to develop quantum memory devices. In recent years, exciting new applications, and more advanced developments of quantum memories, have proliferated. In this review, we outline some of the emerging applications of quantum memories in optical signal processing, quantum computation and non-linear optics. We review recent experimental and theoretical developments, and their impacts on more advanced photonic quantum technologies based on quantum memories. PMID:27695198

  2. Communications: quantum teleportation across the Danube.

    PubMed

    Ursin, Rupert; Jennewein, Thomas; Aspelmeyer, Markus; Kaltenbaek, Rainer; Lindenthal, Michael; Walther, Philip; Zeilinger, Anton

    2004-08-19

    Efficient long-distance quantum teleportation is crucial for quantum communication and quantum networking schemes. Here we describe the high-fidelity teleportation of photons over a distance of 600 metres across the River Danube in Vienna, with the optimal efficiency that can be achieved using linear optics. Our result is a step towards the implementation of a quantum repeater, which will enable pure entanglement to be shared between distant parties in a public environment and eventually on a worldwide scale.

  3. Quantum communications: Teleportation becomes streetwise

    NASA Astrophysics Data System (ADS)

    Grosshans, Frédéric

    2016-10-01

    Quantum teleportation is at the heart of many quantum information protocols. Two teams have now performed it over several kilometres of metropolitan fibre networks, paving the way for future quantum technologies on the city scale.

  4. Polarization tracking for quantum satellite communications

    NASA Astrophysics Data System (ADS)

    Wang, Gang; Shen, Dan; Chen, Genshe; Pham, Khanh; Blasch, Erik

    2014-06-01

    Satellite networks and quantum communications offer complementary opportunities for enhanced operations. Quantum communications provide security for the transmissions between satellites and ground stations; while the free-space link of satellite networks provide the potential of long distance transmission of quantum bits (qubit) for space communications. However, with the promising advantages of the two approaches, challenges remain to fully develop quantum-based satellite communications such as robust and reliable information detection which is difficult to achieve due to the movement of satellites. In this paper, a tracking algorithm is proposed for polarization-encoded quantum satellite communications where polarization states are used to determine the bit transfer between the transmitter and receiver. The polarization tracking is essential for the decoding of a qubit and the quantum key distribution (QKD). A practical channel model for free-space quantum communications is adopted in this paper. With the estimated polarization, a novel dynamic polarization compensation scheme is also proposed. The results show that our methods can accurately estimate the polarization, providing much lower quantum bit error rate (QBER) by compensation, as compared with the direct qubit detection without polarization tracking and compensation scheme.

  5. Software-defined Quantum Communication Systems

    SciTech Connect

    Humble, Travis S; Sadlier, Ronald J

    2014-01-01

    Quantum communication systems harness modern physics through state-of-the-art optical engineering to provide revolutionary capabilities. An important concern for quantum communication engineering is designing and prototyping these systems to prototype proposed capabilities. We apply the paradigm of software-defined communica- tion for engineering quantum communication systems to facilitate rapid prototyping and prototype comparisons. We detail how to decompose quantum communication terminals into functional layers defining hardware, software, and middleware concerns, and we describe how each layer behaves. Using the super-dense coding protocol as a test case, we describe implementations of both the transmitter and receiver, and we present results from numerical simulations of the behavior. We find that while the theoretical benefits of super dense coding are maintained, there is a classical overhead associated with the full implementation.

  6. Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Plecity, Mark S.; Nall, Mark E.

    1991-01-01

    The NASA Advanced Communications Technology Satellite (ACTS) provides high risk technologies having the potential to dramatically enhance the capabilities of the satellite communications industry. This experimental satellite, which will be launched by NASA in 1993, will furnish the technology necessary for providing a range of services. Utilizing the ACTS very-high-gain-hopping spot-beam antennas with on-board routing and processing, Very Small Aperture Terminal (VSAT) digital networks which provide on-demand, full-mesh-convectivity 1.544-MBPS services with only a single hop can be established. The high-gain spot-beam antenna at Ka-band permits wide area, flexible networks providing high data rate services between modest-size earth terminals.

  7. The Holy Grail of quantum optical communication

    SciTech Connect

    García-Patrón, Raúl; Navarrete-Benlloch, Carlos; Lloyd, Seth; Shapiro, Jeffrey H.; Cerf, Nicolas J.

    2014-12-04

    Optical parametric amplifiers together with phase-shifters and beamsplitters have certainly been the most studied objects in the field of quantum optics. Despite such an intensive study, optical parametric amplifiers still keep secrets from us. We will show how they hold the answer to one of the oldest problems in quantum communication theory, namely the calculation of the optimal communication rate of optical channels.

  8. Entanglement-Based Quantum Cryptography and Quantum Communication

    NASA Astrophysics Data System (ADS)

    Zeilinger, Anton

    2007-03-01

    Quantum entanglement, to Erwin Schroedinger the essential feature of quantum mechanics, has become a central resource in various quantum communication protocols including quantum cryptography and quantum teleportation. From a fundamental point of view what is exploited in these experiments is the very fact which led Schroedinger to his statement namely that in entangled states joint properties of the entangled systems may be well defined while the individual subsystems may carry no information at all. In entanglement-based quantum cryptography it leads to the most elegant possible solution of the classic key distribution problem. It implies that the key comes into existence at spatially distant location at the same time and does not need to be transported. A number recent developments include for example highly efficient, robust and stable sources of entangled photons with a broad bandwidth of desired features. Also, entanglement-based quantum cryptography is successfully joining other methods in the work towards demonstrating quantum key distribution networks. Along that line recently decoy-state quantum cryptography over a distance of 144 km between two Canary Islands was demonstrated successfully. Such experiments also open up the possibility of quantum communication on a really large scale using LEO satellites. Another important possible future branch of quantum communication involves quantum repeaters in order to cover larger distances with entangled states. Recently the connection of two fully independent lasers in an entanglement swapping experiment did demonstrate that the timing control of such systems on a femtosecond time scale is possible. A related development includes recent demonstrations of all-optical one-way quantum computation schemes with the extremely short cycle time of only 100 nanoseconds.

  9. Directional coupling for quantum computing and communication.

    PubMed

    Nikolopoulos, Georgios M

    2008-11-14

    We introduce the concept of directional coupling, i.e., the selective transfer of a state between adjacent quantum wires, in the context of quantum computing and communication. Our analysis rests upon a mathematical analogy between a dual-channel directional coupler and a composite spin system.

  10. Nonperturbative approach to relativistic quantum communication channels

    NASA Astrophysics Data System (ADS)

    Landulfo, André G. S.

    2016-05-01

    We investigate the transmission of both classical and quantum information between two arbitrary observers in globally hyperbolic spacetimes using a quantum field as a communication channel. The field is supposed to be in some arbitrary quasifree state and no choice of representation of its canonical commutation relations is made. Both sender and receiver possess some localized two-level quantum system with which they can interact with the quantum field to prepare the input and receive the output of the channel, respectively. The interaction between the two-level systems and the quantum field is such that one can trace out the field degrees of freedom exactly and thus obtain the quantum channel in a nonperturbative way. We end the paper determining the unassisted as well as the entanglement-assisted classical and quantum channel capacities.

  11. Quantum communication with macroscopically bright nonclassical states.

    PubMed

    Usenko, Vladyslav C; Ruppert, Laszlo; Filip, Radim

    2015-11-30

    We analyze homodyne detection of macroscopically bright multimode nonclassical states of light and propose their application in quantum communication. We observe that the homodyne detection is sensitive to a mode-matching of the bright light to the highly intense local oscillator. Unmatched bright modes of light result in additional noise which technically limits detection of Gaussian entanglement at macroscopic level. When the mode-matching is sufficient, we show that multimode quantum key distribution with bright beams is feasible. It finally merges the quantum communication with classical optical technology of visible beams of light.

  12. Communication: Quantum mechanics without wavefunctions

    SciTech Connect

    Schiff, Jeremy; Poirier, Bill

    2012-01-21

    We present a self-contained formulation of spin-free non-relativistic quantum mechanics that makes no use of wavefunctions or complex amplitudes of any kind. Quantum states are represented as ensembles of real-valued quantum trajectories, obtained by extremizing an action and satisfying energy conservation. The theory applies for arbitrary configuration spaces and system dimensionalities. Various beneficial ramifications--theoretical, computational, and interpretational--are discussed.

  13. An exactly solvable model for quantum communications.

    PubMed

    Smith, Graeme; Smolin, John A

    2013-12-12

    Information theory establishes the ultimate limits on performance for noisy communication systems. Accurate models of physical communication devices must include quantum effects, but these typically make the theory intractable. As a result, communication capacities--the maximum possible rates of data transmission--are not known, even for transmission between two users connected by an electromagnetic waveguide with Gaussian noise. Here we present an exactly solvable model of communication with a fully quantum electromagnetic field. This gives explicit expressions for all point-to-point capacities of noisy quantum channels, with implications for quantum key distribution and fibre-optic communications. We also develop a theory of quantum communication networks by solving some rudimentary models including broadcast and multiple-access channels. We compare the predictions of our model with the orthodox Gaussian model and in all cases find agreement to within a few bits. At high signal-to-noise ratios, our simple model captures the relevant physics while remaining amenable to exact solution. PMID:24240277

  14. An exactly solvable model for quantum communications.

    PubMed

    Smith, Graeme; Smolin, John A

    2013-12-12

    Information theory establishes the ultimate limits on performance for noisy communication systems. Accurate models of physical communication devices must include quantum effects, but these typically make the theory intractable. As a result, communication capacities--the maximum possible rates of data transmission--are not known, even for transmission between two users connected by an electromagnetic waveguide with Gaussian noise. Here we present an exactly solvable model of communication with a fully quantum electromagnetic field. This gives explicit expressions for all point-to-point capacities of noisy quantum channels, with implications for quantum key distribution and fibre-optic communications. We also develop a theory of quantum communication networks by solving some rudimentary models including broadcast and multiple-access channels. We compare the predictions of our model with the orthodox Gaussian model and in all cases find agreement to within a few bits. At high signal-to-noise ratios, our simple model captures the relevant physics while remaining amenable to exact solution.

  15. Advanced Communications Technology: Mobile Communications Requirements Report

    NASA Astrophysics Data System (ADS)

    1998-05-01

    The Coast Guard's mobile communications requirements will outstrip existing system capabilities, available capacity, and affordability by the late 1990s. This will require changes in the mix of mobile communications equipment and services used by operational units. New commercial mobile satellite services are available now, with many others arriving on the market between 1998 and 2003. These new services present unique opportunities to satisfy mission requirements, reduce investment in communications infrastructure, and realize more costeffective communications services. The Coast Guard Research and Development Center (R&DC) has undertaken an effort to identify and evaluate current and emerging satellite services that may be used to satisfy Coast Guard mobile communications requirements. As part of this effort, Anteon Corporation has been tasked by R&DC to collect the mobile communications functional requirements that have been identified by program managers. Anteon analysts have reviewed the Government Furnished Information (GFI) and researched other related documentation to identify and collect the requirements that may be used to describe the needed operating environment. Anteon analysts assessed the functional requirements to develop system requirements that describe the features that a communications system must provide to support the functional requirements. This report presents the current and projected Coast Guard mobile communications system requirements.

  16. Secure quantum communication with orthogonal states

    NASA Astrophysics Data System (ADS)

    Shukla, Chitra; Banerjee, Anindita; Pathak, Anirban; Srikanth, R.

    2016-08-01

    In majority of protocols of secure quantum communication (such as, BB84, B92, etc.), the unconditional security of the protocols are obtained by using conjugate coding (two or more mutually unbiased bases (MUBs)). Initially, all the conjugate-coding-based protocols of secure quantum communication were restricted to quantum key distribution (QKD), but later on they were extended to other cryptographic tasks (such as, secure direct quantum communication and quantum key agreement). In contrast to the conjugate-coding-based protocols, a few completely orthogonal-state-based protocols of unconditionally secure QKD (such as, Goldenberg-Vaidman and N09) were also proposed. However, till the recent past, orthogonal-state-based protocols were only a theoretical concept and were limited to QKD. Only recently, orthogonal-state-based protocols of QKD are experimentally realized and extended to cryptographic tasks beyond QKD. This paper aims to briefly review the orthogonal-state-based protocols of secure quantum communication that are recently introduced by our group and other researchers.

  17. Controlled bidirectional quantum secure direct communication.

    PubMed

    Chou, Yao-Hsin; Lin, Yu-Ting; Zeng, Guo-Jyun; Lin, Fang-Jhu; Chen, Chi-Yuan

    2014-01-01

    We propose a novel protocol for controlled bidirectional quantum secure communication based on a nonlocal swap gate scheme. Our proposed protocol would be applied to a system in which a controller (supervisor/Charlie) controls the bidirectional communication with quantum information or secret messages between legitimate users (Alice and Bob). In this system, the legitimate users must obtain permission from the controller in order to exchange their respective quantum information or secret messages simultaneously; the controller is unable to obtain any quantum information or secret messages from the decoding process. Moreover, the presence of the controller also avoids the problem of one legitimate user receiving the quantum information or secret message before the other, and then refusing to help the other user decode the quantum information or secret message. Our proposed protocol is aimed at protecting against external and participant attacks on such a system, and the cost of transmitting quantum bits using our protocol is less than that achieved in other studies. Based on the nonlocal swap gate scheme, the legitimate users exchange their quantum information or secret messages without transmission in a public channel, thus protecting against eavesdroppers stealing the secret messages.

  18. Controlled Bidirectional Quantum Secure Direct Communication

    PubMed Central

    Chou, Yao-Hsin; Lin, Yu-Ting; Zeng, Guo-Jyun; Lin, Fang-Jhu; Chen, Chi-Yuan

    2014-01-01

    We propose a novel protocol for controlled bidirectional quantum secure communication based on a nonlocal swap gate scheme. Our proposed protocol would be applied to a system in which a controller (supervisor/Charlie) controls the bidirectional communication with quantum information or secret messages between legitimate users (Alice and Bob). In this system, the legitimate users must obtain permission from the controller in order to exchange their respective quantum information or secret messages simultaneously; the controller is unable to obtain any quantum information or secret messages from the decoding process. Moreover, the presence of the controller also avoids the problem of one legitimate user receiving the quantum information or secret message before the other, and then refusing to help the other user decode the quantum information or secret message. Our proposed protocol is aimed at protecting against external and participant attacks on such a system, and the cost of transmitting quantum bits using our protocol is less than that achieved in other studies. Based on the nonlocal swap gate scheme, the legitimate users exchange their quantum information or secret messages without transmission in a public channel, thus protecting against eavesdroppers stealing the secret messages. PMID:25006596

  19. Classical communication cost of quantum steering

    NASA Astrophysics Data System (ADS)

    Sainz, Ana Belén; Aolita, Leandro; Brunner, Nicolas; Gallego, Rodrigo; Skrzypczyk, Paul

    2016-07-01

    Quantum steering is observed when performing appropriate local measurements on an entangled state. Here we discuss the possibility of simulating classically this effect, using classical communication instead of entanglement. We show that infinite communication is necessary for exactly simulating steering for any pure entangled state, as well as for a class of mixed entangled states. Moreover, we discuss the communication cost of steering for general entangled states, as well as approximate simulation. Our findings reveal striking differences between Bell nonlocality and steering and provide a natural way of measuring the strength of the latter.

  20. The quantum cryptograpy: Communication and computation

    NASA Astrophysics Data System (ADS)

    Delicado, Raquel Fernandez; Cabello, David Bellver; Boada, Ivan Lloro

    2005-07-01

    Nowadays there are two secure ways of encrypting information, the public key cryptography (PKC), and the symmetric cryptography (SC). With the arrival of the quantum computation, both methods become vulnerable, thanks to its exponential-growing calculation capacity. To solve this lack of security, quantum physics nowadays offers us two satisfactory methods which have been proposed successfully from a theoretical point of view: the two non-commuting observables, based on the Bennet and Brassard protocol, and the quantum entanglement combined with the Bell's inequality theorem, based on the Ekert protocol. Since some experiments have demonstrated the viability of the conduction of free space quantum cryptography at the surface of the Earth, we propose that this could be a boost for secure ground-to-satellite or satellite-to-satellite communications.

  1. Quantum chromodynamics with advanced computing

    SciTech Connect

    Kronfeld, Andreas S.; /Fermilab

    2008-07-01

    We survey results in lattice quantum chromodynamics from groups in the USQCD Collaboration. The main focus is on physics, but many aspects of the discussion are aimed at an audience of computational physicists.

  2. Quantum information theory: classical communication over quantum channels

    NASA Astrophysics Data System (ADS)

    Cortese, John Anthony

    This thesis studies classical communication over quantum channels. Chapter 1 describes an algebraic technique which extends several previously known qubit channel capacity results to the qudit quantum channel case. Chapter 2 derives a formula for the relative entropy function of two qubit density matrices in terms of their Bloch vectors. The application of the Bloch vector relative entropy formula to the determination of Holevo-Schumacher-Westmoreland (HSW) capacities for qubit quantum channels is discussed. Chapter 3 outlines several numerical simulation results which support theoretical conclusions and conjectures discussed in Chapters 1 and 2. Chapter 4 closes the thesis with comments, examples and discussion on the additivity of Holevo Chi and the HSW channel capacity.

  3. Quantum noise limits to terabaud communications

    NASA Astrophysics Data System (ADS)

    Corney, J. F.; Drummond, P. D.; Liebman, A.

    1997-08-01

    From a general model of fiber optics, we investigate the physical limits of soliton-based terabaud communication systems. In particular we consider Raman and initial quantum noise effects which are often neglected in fiber communications. Simulations of the position diffusion in dark and bright solitons show that these effects become increasingly important at short pulse durations, even over kilometer-scale distances. We also obtain an approximate analytic theory in agreement with numerical simulations, which shows that the Raman effects exceed the Gordon-Haus jitter for sub-picosecond pulses.

  4. Communication capacity of mixed quantum t -designs

    NASA Astrophysics Data System (ADS)

    Brandsen, Sarah; Dall'Arno, Michele; Szymusiak, Anna

    2016-08-01

    We operationally introduce mixed quantum t -designs as the most general arbitrary-rank extension of projective quantum t -designs which preserves indistinguishability from the uniform distribution for t copies. First, we derive upper bounds on the classical communication capacity of any mixed t -design measurement for t ∈[1 ,5 ] . Second, we explicitly compute the classical communication capacity of several mixed t -design measurements, including the depolarized version of any qubit and qutrit symmetric, informationally complete (SIC) measurement and complete mutually unbiased bases, the qubit icosahedral measurement, the Hoggar SIC measurement, any anti-SIC (where each element is proportional to the projector on the subspace orthogonal to one of the elements of the original SIC), and the uniform distribution over pure effects.

  5. Experimental demonstration of counterfactual quantum communication.

    PubMed

    Liu, Yang; Ju, Lei; Liang, Xiao-Lei; Tang, Shi-Biao; Tu, Guo-Liang Shen; Zhou, Lei; Peng, Cheng-Zhi; Chen, Kai; Chen, Teng-Yun; Chen, Zeng-Bing; Pan, Jian-Wei

    2012-07-20

    Quantum effects, besides offering substantial superiority in many tasks over classical methods, are also expected to provide interesting ways to establish secret keys between remote parties. A striking scheme called "counterfactual quantum cryptography" proposed by Noh [Phys. Rev. Lett. 103, 230501 (2009).] allows one to maintain secure key distributions, in which particles carrying secret information are seemingly not being transmitted through quantum channels. We have experimentally demonstrated, for the first time, a faithful implementation for such a scheme with an on-table realization operating at telecom wavelengths. To verify its feasibility for extension over a long distance, we have furthermore reported an illustration on a 1 km fiber. In both cases, high visibilities of more than 98% are achieved through active stabilization of interferometers. Our demonstration is crucial as a direct verification of such a remarkable application, and this procedure can become a key communication module for revealing fundamental physics through counterfactuals.

  6. Experimental demonstration of counterfactual quantum communication.

    PubMed

    Liu, Yang; Ju, Lei; Liang, Xiao-Lei; Tang, Shi-Biao; Tu, Guo-Liang Shen; Zhou, Lei; Peng, Cheng-Zhi; Chen, Kai; Chen, Teng-Yun; Chen, Zeng-Bing; Pan, Jian-Wei

    2012-07-20

    Quantum effects, besides offering substantial superiority in many tasks over classical methods, are also expected to provide interesting ways to establish secret keys between remote parties. A striking scheme called "counterfactual quantum cryptography" proposed by Noh [Phys. Rev. Lett. 103, 230501 (2009).] allows one to maintain secure key distributions, in which particles carrying secret information are seemingly not being transmitted through quantum channels. We have experimentally demonstrated, for the first time, a faithful implementation for such a scheme with an on-table realization operating at telecom wavelengths. To verify its feasibility for extension over a long distance, we have furthermore reported an illustration on a 1 km fiber. In both cases, high visibilities of more than 98% are achieved through active stabilization of interferometers. Our demonstration is crucial as a direct verification of such a remarkable application, and this procedure can become a key communication module for revealing fundamental physics through counterfactuals. PMID:22861830

  7. Entanglement enhances security in quantum communication

    SciTech Connect

    Demkowicz-Dobrzanski, Rafal; Sen, Aditi; Sen, Ujjwal; Lewenstein, Maciej

    2009-07-15

    Secret sharing is a protocol in which a 'boss' wants to send a classical message secretly to two 'subordinates', such that none of the subordinates is able to know the message alone, while they can find it if they cooperate. Quantum mechanics is known to allow for such a possibility. We analyze tolerable quantum bit error rates in such secret sharing protocols in the physically relevant case when the eavesdropping is local with respect to the two channels of information transfer from the boss to the two subordinates. We find that using entangled encoding states is advantageous to legitimate users of the protocol. We therefore find that entanglement is useful for secure quantum communication. We also find that bound entangled states with positive partial transpose are not useful as a local eavesdropping resource. Moreover, we provide a criterion for security in secret sharing--a parallel of the Csiszar-Koerner criterion in single-receiver classical cryptography.

  8. Coherent communication with continuous quantum variables

    SciTech Connect

    Wilde, Mark M.; Krovi, Hari; Brun, Todd A.

    2007-06-15

    The coherent bit (cobit) channel is a resource intermediate between classical and quantum communication. It produces coherent versions of teleportation and superdense coding. We extend the cobit channel to continuous variables by providing a definition of the coherent nat (conat) channel. We construct several coherent protocols that use both a position-quadrature and a momentum-quadrature conat channel with finite squeezing. Finally, we show that the quality of squeezing diminishes through successive compositions of coherent teleportation and superdense coding.

  9. Memory assisted free space quantum communication

    NASA Astrophysics Data System (ADS)

    Jordaan, Bertus; Namazi, Mehdi; Goham, Connor; Shahrokhshahi, Reihaneh; Vallone, Giuseppe; Villoresi, Paolo; Figueroa, Eden

    2016-05-01

    A quantum memory assisted node between different quantum channels has the capability to modify and synchronize its output, allowing for easy connectivity, and advanced cryptography protocols. We present the experimental progress towards the storage of single photon level pulses carrying random polarization qubits into a dual rail room temperature quantum memory (RTQM) after ~ 20m of free space propagation. The RTQM coherently stores the input pulses through electromagnetically induced transparency (EIT) of a warm 87 Rb vapor and filters the output by polarization elements and temperature-controlled etalon resonators. This allows the characterization of error rates for each polarization basis and the testing of the synchronization ability of the quantum memory. This work presents a steppingstone towards quantum key distribution and quantum repeater networks. The work was supported by the US-Navy Office of Naval Research, Grant Number N00141410801 and the Simons Foundation, Grant Number SBF241180.B. J. acknowledges financial assistance of the National Research Foundation (NRF) of South Africa.

  10. Quantum Limits of Space-to-Ground Optical Communications

    NASA Technical Reports Server (NTRS)

    Hemmati, H.; Dolinar, S.

    2012-01-01

    Quantum limiting factors contributed by the transmitter, the optical channel, and the receiver of a space-to-ground optical communications link are described. Approaches to move toward the ultimate quantum limit are discussed.

  11. Three-Party Quantum Network Communication Protocols Based on Quantum Teleportation

    NASA Astrophysics Data System (ADS)

    Zhou, Nan-Run; Cheng, Hu-Lai; Gong, Li-Hua; Li, Chi-Sheng

    2014-04-01

    By utilizing the delocalized correlation of entangled states in quantum information theory, a novel method on acknowledgments of quantum information among three-party is presented, and then two three-party quantum network communication protocols based on quantum teleportation are presented, namely, three-party stop-wait quantum communication protocol and three-party selective automatic repeat quantum communication protocol. In the two proposed protocols, the data frames composed of qubits are teleported via three-party quantum teleportation, the two receivers simultaneously receive quantum frames from the sender, and then return quantum acknowledgment frames or quantum negative acknowledgment frames via quantum entanglement channels. The sender simultaneously receives and deals with quantum acknowledgment frames and quantum negative acknowledgment frames from the two receivers, thus the processing delay on returning quantum frames is reduced. And due to the transience of transferring quantum information, the returning of quantum acknowledgment frames and quantum negative acknowledgment frames are completed instantaneously, the proposed protocols reduce the transmission delay and improve the communication efficiency. During the whole course of communications, the classical channels are only used to transmit the measurement message, so the burdens of classical channels are reduced.

  12. Atmospheric continuous-variable quantum communication

    NASA Astrophysics Data System (ADS)

    Heim, B.; Peuntinger, C.; Killoran, N.; Khan, I.; Wittmann, C.; Marquardt, Ch; Leuchs, G.

    2014-11-01

    We present a quantum communication experiment conducted over a point-to-point free-space link of 1.6 km in urban conditions. We study atmospheric influences on the capability of the link to act as a continuous-variable (CV) quantum channel. Continuous polarization states (that contain the signal encoding as well as a local oscillator (LO) in the same spatial mode) are prepared and sent over the link in a polarization multiplexed setting. Both signal and LO undergo the same atmospheric fluctuations. These are intrinsically auto-compensated which removes detrimental influences on the interferometric visibility. At the receiver, we measure the Q-function and interpret the data using the framework of effective entanglement (EE). We compare different state amplitudes and alphabets (two-state and four-state) and determine their optimal working points with respect to the distributed EE. Based on the high entanglement transmission rates achieved, our system indicates the high potential of atmospheric links in the field of CV quantum key distribution.

  13. Quantum communication complexity advantage implies violation of a Bell inequality.

    PubMed

    Buhrman, Harry; Czekaj, Łukasz; Grudka, Andrzej; Horodecki, Michał; Horodecki, Paweł; Markiewicz, Marcin; Speelman, Florian; Strelchuk, Sergii

    2016-03-22

    We obtain a general connection between a large quantum advantage in communication complexity and Bell nonlocality. We show that given any protocol offering a sufficiently large quantum advantage in communication complexity, there exists a way of obtaining measurement statistics that violate some Bell inequality. Our main tool is port-based teleportation. If the gap between quantum and classical communication complexity can grow arbitrarily large, the ratio of the quantum value to the classical value of the Bell quantity becomes unbounded with the increase in the number of inputs and outputs. PMID:26957600

  14. Quantum communication complexity advantage implies violation of a Bell inequality

    PubMed Central

    Buhrman, Harry; Czekaj, Łukasz; Grudka, Andrzej; Horodecki, Michał; Horodecki, Paweł; Markiewicz, Marcin; Speelman, Florian; Strelchuk, Sergii

    2016-01-01

    We obtain a general connection between a large quantum advantage in communication complexity and Bell nonlocality. We show that given any protocol offering a sufficiently large quantum advantage in communication complexity, there exists a way of obtaining measurement statistics that violate some Bell inequality. Our main tool is port-based teleportation. If the gap between quantum and classical communication complexity can grow arbitrarily large, the ratio of the quantum value to the classical value of the Bell quantity becomes unbounded with the increase in the number of inputs and outputs. PMID:26957600

  15. Quantum communication complexity advantage implies violation of a Bell inequality

    NASA Astrophysics Data System (ADS)

    Buhrman, Harry; Czekaj, Łukasz; Grudka, Andrzej; Horodecki, Michał; Horodecki, Paweł; Markiewicz, Marcin; Speelman, Florian; Strelchuk, Sergii

    2016-03-01

    We obtain a general connection between a large quantum advantage in communication complexity and Bell nonlocality. We show that given any protocol offering a sufficiently large quantum advantage in communication complexity, there exists a way of obtaining measurement statistics that violate some Bell inequality. Our main tool is port-based teleportation. If the gap between quantum and classical communication complexity can grow arbitrarily large, the ratio of the quantum value to the classical value of the Bell quantity becomes unbounded with the increase in the number of inputs and outputs.

  16. Quantum communication complexity advantage implies violation of a Bell inequality.

    PubMed

    Buhrman, Harry; Czekaj, Łukasz; Grudka, Andrzej; Horodecki, Michał; Horodecki, Paweł; Markiewicz, Marcin; Speelman, Florian; Strelchuk, Sergii

    2016-03-22

    We obtain a general connection between a large quantum advantage in communication complexity and Bell nonlocality. We show that given any protocol offering a sufficiently large quantum advantage in communication complexity, there exists a way of obtaining measurement statistics that violate some Bell inequality. Our main tool is port-based teleportation. If the gap between quantum and classical communication complexity can grow arbitrarily large, the ratio of the quantum value to the classical value of the Bell quantity becomes unbounded with the increase in the number of inputs and outputs.

  17. Multiplexed communication over a high-speed quantum channel

    NASA Astrophysics Data System (ADS)

    Heurs, M.; Webb, J. G.; Dunlop, A. E.; Harb, C. C.; Ralph, T. C.; Huntington, E. H.

    2010-03-01

    In quantum information systems it is of particular interest to consider the best way in which to use the nonclassical resources consumed by that system. Quantum communication protocols are integral to quantum information systems and are among the most promising near-term applications of quantum information science. Here we show that a multiplexed, digital quantum communications system supported by a comb of vacuum squeezing has a greater channel capacity per photon than a source of broadband squeezing with the same analog band width. We report on the time-resolved, simultaneous observation of the first dozen teeth in a 2.4-GHz comb of vacuum squeezing produced by a subthreshold optical parametric oscillator, as required for such a quantum communications channel. We also demonstrate multiplexed communication on that channel.

  18. Multiplexed communication over a high-speed quantum channel

    SciTech Connect

    Heurs, M.; Webb, J. G.; Dunlop, A. E.; Harb, C. C.; Huntington, E. H.; Ralph, T. C.

    2010-03-15

    In quantum information systems it is of particular interest to consider the best way in which to use the nonclassical resources consumed by that system. Quantum communication protocols are integral to quantum information systems and are among the most promising near-term applications of quantum information science. Here we show that a multiplexed, digital quantum communications system supported by a comb of vacuum squeezing has a greater channel capacity per photon than a source of broadband squeezing with the same analog band width. We report on the time-resolved, simultaneous observation of the first dozen teeth in a 2.4-GHz comb of vacuum squeezing produced by a subthreshold optical parametric oscillator, as required for such a quantum communications channel. We also demonstrate multiplexed communication on that channel.

  19. Quantum Communication for the Ultimate Capacity and Security

    NASA Astrophysics Data System (ADS)

    Sasaki, Masahide; Fujiwara, Mikio; Takeoka, Masahiro

    Quantum info-communication technologies (Q-ICT) will be able to realize quantum communication which attains higher capacity than that of conventional optical communications, and the unconditionally secure communication, known as quantum key distribution (QKD), that cannot be broken by any future technologies. In this article we first review a brief history of Q-ICT, and introduce basic notions and results so far. We then present our recent results on these two technologies, addressing current limitations of the known schemes, and finally discuss future perspectives, especially a challenge to merge the merits of the two.

  20. Efficient Controlled Quantum Secure Direct Communication Protocols

    NASA Astrophysics Data System (ADS)

    Patwardhan, Siddharth; Moulick, Subhayan Roy; Panigrahi, Prasanta K.

    2016-07-01

    We study controlled quantum secure direct communication (CQSDC), a cryptographic scheme where a sender can send a secret bit-string to an intended recipient, without any secure classical channel, who can obtain the complete bit-string only with the permission of a controller. We report an efficient protocol to realize CQSDC using Cluster state and then go on to construct a (2-3)-CQSDC using Brown state, where a coalition of any two of the three controllers is required to retrieve the complete message. We argue both protocols to be unconditionally secure and analyze the efficiency of the protocols to show it to outperform the existing schemes while maintaining the same security specifications.

  1. Novel systems and methods for quantum communication, quantum computation, and quantum simulation

    NASA Astrophysics Data System (ADS)

    Gorshkov, Alexey Vyacheslavovich

    Precise control over quantum systems can enable the realization of fascinating applications such as powerful computers, secure communication devices, and simulators that can elucidate the physics of complex condensed matter systems. However, the fragility of quantum effects makes it very difficult to harness the power of quantum mechanics. In this thesis, we present novel systems and tools for gaining fundamental insights into the complex quantum world and for bringing practical applications of quantum mechanics closer to reality. We first optimize and show equivalence between a wide range of techniques for storage of photons in atomic ensembles. We describe experiments demonstrating the potential of our optimization algorithms for quantum communication and computation applications. Next, we combine the technique of photon storage with strong atom-atom interactions to propose a robust protocol for implementing the two-qubit photonic phase gate, which is an important ingredient in many quantum computation and communication tasks. In contrast to photon storage, many quantum computation and simulation applications require individual addressing of closely-spaced atoms, ions, quantum dots, or solid state defects. To meet this requirement, we propose a method for coherent optical far-field manipulation of quantum systems with a resolution that is not limited by the wavelength of radiation. While alkali atoms are currently the system of choice for photon storage and many other applications, we develop new methods for quantum information processing and quantum simulation with ultracold alkaline-earth atoms in optical lattices. We show how multiple qubits can be encoded in individual alkaline-earth atoms and harnessed for quantum computing and precision measurements applications. We also demonstrate that alkaline-earth atoms can be used to simulate highly symmetric systems exhibiting spin-orbital interactions and capable of providing valuable insights into strongly

  2. Fault-tolerant Remote Quantum Entanglement Establishment for Secure Quantum Communications

    NASA Astrophysics Data System (ADS)

    Tsai, Chia-Wei; Lin, Jason

    2016-07-01

    This work presents a strategy for constructing long-distance quantum communications among a number of remote users through collective-noise channel. With the assistance of semi-honest quantum certificate authorities (QCAs), the remote users can share a secret key through fault-tolerant entanglement swapping. The proposed protocol is feasible for large-scale distributed quantum networks with numerous users. Each pair of communicating parties only needs to establish the quantum channels and the classical authenticated channels with his/her local QCA. Thus, it enables any user to communicate freely without point-to-point pre-establishing any communication channels, which is efficient and feasible for practical environments.

  3. Exponential Communication Complexity Advantage from Quantum Superposition of the Direction of Communication

    NASA Astrophysics Data System (ADS)

    Guérin, Philippe Allard; Feix, Adrien; Araújo, Mateus; Brukner, Časlav

    2016-09-01

    In communication complexity, a number of distant parties have the task of calculating a distributed function of their inputs, while minimizing the amount of communication between them. It is known that with quantum resources, such as entanglement and quantum channels, one can obtain significant reductions in the communication complexity of some tasks. In this work, we study the role of the quantum superposition of the direction of communication as a resource for communication complexity. We present a tripartite communication task for which such a superposition allows for an exponential saving in communication, compared to one-way quantum (or classical) communication; the advantage also holds when we allow for protocols with bounded error probability.

  4. Exponential Communication Complexity Advantage from Quantum Superposition of the Direction of Communication.

    PubMed

    Guérin, Philippe Allard; Feix, Adrien; Araújo, Mateus; Brukner, Časlav

    2016-09-01

    In communication complexity, a number of distant parties have the task of calculating a distributed function of their inputs, while minimizing the amount of communication between them. It is known that with quantum resources, such as entanglement and quantum channels, one can obtain significant reductions in the communication complexity of some tasks. In this work, we study the role of the quantum superposition of the direction of communication as a resource for communication complexity. We present a tripartite communication task for which such a superposition allows for an exponential saving in communication, compared to one-way quantum (or classical) communication; the advantage also holds when we allow for protocols with bounded error probability.

  5. Exponential Communication Complexity Advantage from Quantum Superposition of the Direction of Communication.

    PubMed

    Guérin, Philippe Allard; Feix, Adrien; Araújo, Mateus; Brukner, Časlav

    2016-09-01

    In communication complexity, a number of distant parties have the task of calculating a distributed function of their inputs, while minimizing the amount of communication between them. It is known that with quantum resources, such as entanglement and quantum channels, one can obtain significant reductions in the communication complexity of some tasks. In this work, we study the role of the quantum superposition of the direction of communication as a resource for communication complexity. We present a tripartite communication task for which such a superposition allows for an exponential saving in communication, compared to one-way quantum (or classical) communication; the advantage also holds when we allow for protocols with bounded error probability. PMID:27636460

  6. Robust Timing Synchronization for Aviation Communications, and Efficient Modulation and Coding Study for Quantum Communication

    NASA Technical Reports Server (NTRS)

    Xiong, Fugin

    2003-01-01

    One half of Professor Xiong's effort will investigate robust timing synchronization schemes for dynamically varying characteristics of aviation communication channels. The other half of his time will focus on efficient modulation and coding study for the emerging quantum communications.

  7. Advanced Approach of Multiagent Based Buoy Communication

    PubMed Central

    Gricius, Gediminas; Drungilas, Darius; Andziulis, Arunas; Dzemydiene, Dale; Voznak, Miroslav; Kurmis, Mindaugas; Jakovlev, Sergej

    2015-01-01

    Usually, a hydrometeorological information system is faced with great data flows, but the data levels are often excessive, depending on the observed region of the water. The paper presents advanced buoy communication technologies based on multiagent interaction and data exchange between several monitoring system nodes. The proposed management of buoy communication is based on a clustering algorithm, which enables the performance of the hydrometeorological information system to be enhanced. The experiment is based on the design and analysis of the inexpensive but reliable Baltic Sea autonomous monitoring network (buoys), which would be able to continuously monitor and collect temperature, waviness, and other required data. The proposed approach of multiagent based buoy communication enables all the data from the costal-based station to be monitored with limited transition speed by setting different tasks for the agent-based buoy system according to the clustering information. PMID:26345197

  8. Quantum receiver beyond the standard quantum limit of coherent optical communication.

    PubMed

    Tsujino, Kenji; Fukuda, Daiji; Fujii, Go; Inoue, Shuichiro; Fujiwara, Mikio; Takeoka, Masahiro; Sasaki, Masahide

    2011-06-24

    The most efficient modern optical communication is known as coherent communication, and its standard quantum limit is almost reachable with current technology. Though it has been predicted for a long time that this standard quantum limit could be overcome via quantum mechanically optimized receivers, such a performance has not been experimentally realized so far. Here we demonstrate the first unconditional evidence surpassing the standard quantum limit of coherent optical communication. We implement a quantum receiver with a simple linear optics configuration and achieve more than 90% of the total detection efficiency of the system. Such an efficient quantum receiver will provide a new way of extending the distance of amplification-free channels, as well as of realizing quantum information protocols based on coherent states and the loophole-free test of quantum mechanics.

  9. Simulation and test platform for free-space quantum communication

    NASA Astrophysics Data System (ADS)

    Jiang, Hao; Jia, Jianjun; Wang, Jianyu

    2012-10-01

    We propose a simulation and test platform for free-space quantum communication. The platform is used to simulate the working condition of the satellite-to-ground quantum communication, test the technical parameters and performance of the quantum communication terminal. A collimator is used to simulate the far-field optical transmission between the satellite and the ground; A turntable is used to simulate the motion between the satellite and the ground; A voice coil motor fast steering mirror is used to simulate the vibration of the satellite. With this platform, we design experiments to test the quantum communication terminal we developed. Its acquisition, tracking and pointing (ATP) performance and the far-field distribution of the communication photons are tested, the test results are provided and analyzed.

  10. Long distance quantum communication using continuous variable encoding

    NASA Astrophysics Data System (ADS)

    Li, Linshu; Albert, Victor; Michael, Marios; Muralidharan, Sreraman; Zou, Changling; Jiang, Liang

    Quantum communication enables faithful quantum state transfer between different parties and protocols for cryptographic purposes. However, quantum communication over long distances (>1000km) remains challenging due to optical channel attenuation. This calls for investigation on developing novel encoding schemes that correct photon loss errors efficiently. In this talk, we introduce the generalization of multi-component Schrödinger cat states and propose to encode quantum information in these cat states for ultrafast quantum repeaters. We detail the quantum error correction procedures at each repeater station and characterize the performance of this novel encoding scheme given practical imperfections, such as coupling loss. A comparison with other quantum error correcting codes for bosonic modes will be discussed.

  11. Distributed wireless quantum communication networks with partially entangled pairs

    NASA Astrophysics Data System (ADS)

    Yu, Xu-Tao; Zhang, Zai-Chen; Xu, Jin

    2014-01-01

    Wireless quantum communication networks transfer quantum state by teleportation. Existing research focuses on maximal entangled pairs. In this paper, we analyse the distributed wireless quantum communication networks with partially entangled pairs. A quantum routing scheme with multi-hop teleportation is proposed. With the proposed scheme, is not necessary for the quantum path to be consistent with the classical path. The quantum path and its associated classical path are established in a distributed way. Direct multi-hop teleportation is conducted on the selected path to transfer a quantum state from the source to the destination. Based on the feature of multi-hop teleportation using partially entangled pairs, if the node number of the quantum path is even, the destination node will add another teleportation at itself. We simulated the performance of distributed wireless quantum communication networks with a partially entangled state. The probability of transferring the quantum state successfully is statistically analyzed. Our work shows that multi-hop teleportation on distributed wireless quantum networks with partially entangled pairs is feasible.

  12. Long-distance measurement-device-independent multiparty quantum communication.

    PubMed

    Fu, Yao; Yin, Hua-Lei; Chen, Teng-Yun; Chen, Zeng-Bing

    2015-03-01

    The Greenberger-Horne-Zeilinger (GHZ) entanglement, originally introduced to uncover the extreme violation of local realism against quantum mechanics, is an important resource for multiparty quantum communication tasks. But the low intensity and fragility of the GHZ entanglement source in current conditions have made the practical applications of these multiparty tasks an experimental challenge. Here we propose a feasible scheme for practically distributing the postselected GHZ entanglement over a distance of more than 100 km for experimentally accessible parameter regimes. Combining the decoy-state and measurement-device-independent protocols for quantum key distribution, we anticipate that our proposal suggests an important avenue for practical multiparty quantum communication.

  13. Quantum communication through a spin ring with twisted boundary conditions

    SciTech Connect

    Bose, S.; Jin, B.-Q.; Korepin, V.E.

    2005-08-15

    We investigate quantum communication between the sites of a spin ring with twisted boundary conditions. Such boundary conditions can be achieved by a magnetic flux through the ring. We find that a nonzero twist can improve communication through finite odd-numbered rings and enable high-fidelity multiparty quantum communication through spin rings (working near perfectly for rings of five and seven spins). We show that in certain cases, the twist results in the complete blockage of quantum-information flow to a certain site of the ring. This effect can be exploited to interface and entangle a flux qubit and a spin qubit without embedding the latter in a magnetic field.

  14. Advanced Communications Architecture Demonstration Made Significant Progress

    NASA Technical Reports Server (NTRS)

    Carek, David Andrew

    2004-01-01

    Simulation for a ground station located at 44.5 deg latitude. The Advanced Communications Architecture Demonstration (ACAD) is a concept architecture to provide high-rate Ka-band (27-GHz) direct-to-ground delivery of payload data from the International Space Station. This new concept in delivering data from the space station targets scientific experiments that buffer data onboard. The concept design provides a method to augment the current downlink capability through the Tracking Data Relay Satellite System (TDRSS) Ku-band (15-GHz) communications system. The ACAD concept pushes the limits of technology in high-rate data communications for space-qualified systems. Research activities are ongoing in examining the various aspects of high-rate communications systems including: (1) link budget parametric analyses, (2) antenna configuration trade studies, (3) orbital simulations (see the preceding figure), (4) optimization of ground station contact time (see the following graph), (5) processor and storage architecture definition, and (6) protocol evaluations and dependencies.

  15. Communication services for advanced network applications.

    SciTech Connect

    Bresnahan, J.; Foster, I.; Insley, J.; Toonen, B.; Tuecke, S.

    1999-06-10

    Advanced network applications such as remote instrument control, collaborative environments, and remote I/O are distinguished by traditional applications such as videoconferencing by their need to create multiple, heterogeneous flows with different characteristics. For example, a single application may require remote I/O for raw datasets, shared controls for a collaborative analysis system, streaming video for image rendering data, and audio for collaboration. Furthermore, each flow can have different requirements in terms of reliability, network quality of service, security, etc. They argue that new approaches to communication services, protocols, and network architecture are required both to provide high-level abstractions for common flow types and to support user-level management of flow creation and quality. They describe experiences with the development of such applications and communication services.

  16. Quantum Sensing and Communications Being Developed for Nanotechnology

    NASA Technical Reports Server (NTRS)

    Lekki, John D.; Nguyen, Quang-Viet

    2005-01-01

    An interdisciplinary quantum communications and sensing research effort for application in microdevices has been underway at the NASA Glenn Research Center since 2000. Researchers in Glenn's Instrumentation and Controls, Communications Technology, and Propulsion and Turbomachinery Divisions have been working together to study and develop techniques that utilize quantum effects for sensing and communications. The emerging technology provides an innovative way to communicate faster and farther using less power and to sense, measure, and image environmental properties in ways that are not possible with existing technology.

  17. Secure satellite communication using multi-photon tolerant quantum communication protocol

    NASA Astrophysics Data System (ADS)

    Darunkar, Bhagyashri; Punekar, Nikhil; Verma, Pramode K.

    2015-09-01

    This paper proposes and analyzes the potential of a multi-photon tolerant quantum communication protocol to secure satellite communication. For securing satellite communication, quantum cryptography is the only known unconditionally secure method. A number of recent experiments have shown feasibility of satellite-aided global quantum key distribution (QKD) using different methods such as: Use of entangled photon pairs, decoy state methods, and entanglement swapping. The use of single photon in these methods restricts the distance and speed over which quantum cryptography can be applied. Contemporary quantum cryptography protocols like the BB84 and its variants suffer from the limitation of reaching the distances of only Low Earth Orbit (LEO) at the data rates of few kilobits per second. This makes it impossible to develop a general satellite-based secure global communication network using the existing protocols. The method proposed in this paper allows secure communication at the heights of the Medium Earth Orbit (MEO) and Geosynchronous Earth Orbit (GEO) satellites. The benefits of the proposed method are two-fold: First it enables the realization of a secure global communication network based on satellites and second it provides unconditional security for satellite networks at GEO heights. The multi-photon approach discussed in this paper ameliorates the distance and speed issues associated with quantum cryptography through the use of contemporary laser communication (lasercom) devices. This approach can be seen as a step ahead towards global quantum communication.

  18. Epistemic view of quantum states and communication complexity of quantum channels.

    PubMed

    Montina, Alberto

    2012-09-14

    The communication complexity of a quantum channel is the minimal amount of classical communication required for classically simulating a process of state preparation, transmission through the channel and subsequent measurement. It establishes a limit on the power of quantum communication in terms of classical resources. We show that classical simulations employing a finite amount of communication can be derived from a special class of hidden variable theories where quantum states represent statistical knowledge about the classical state and not an element of reality. This special class has attracted strong interest very recently. The communication cost of each derived simulation is given by the mutual information between the quantum state and the classical state of the parent hidden variable theory. Finally, we find that the communication complexity for single qubits is smaller than 1.28 bits. The previous known upper bound was 1.85 bits.

  19. Eavesdropping of quantum communication from a noninertial frame

    SciTech Connect

    Bradler, K.

    2007-02-15

    We introduce a relativistic version of the quantum encryption protocol by considering two inertial observers who wish to securely transmit quantum information encoded in a free scalar quantum field state forming Minkowski particles. In a nonrelativistic setting a certain amount of shared classical resources is necessary to perfectly encrypt the state. We show that in the case of a uniformly accelerated eavesdropper the communicating parties need to share (asymptotically in the limit of infinite acceleration) just half of the classical resources.

  20. The ACTS Flight System - Cost-Effective Advanced Communications Technology. [Advanced Communication Technology Satellite

    NASA Technical Reports Server (NTRS)

    Holmes, W. M., Jr.; Beck, G. A.

    1984-01-01

    The multibeam communications package (MCP) for the Advanced Communications Technology Satellite (ACTS) to be STS-launched by NASA in 1988 for experimental demonstration of satellite-switched TDMA (at 220 Mbit/sec) and baseband-processor signal routing (at 110 or 27.5 Mbit/sec) is characterized. The developmental history of the ACTS, the program definition, and the spacecraft-bus and MCP parameters are reviewed and illustrated with drawings, block diagrams, and maps of the coverage plan. Advanced features of the MPC include 4.5-dB-noise-figure 30-GHz FET amplifiers and 20-GHz TWTA transmitters which provide either 40-W or 8-W RF output, depending on rain conditions. The technologies being tested in ACTS can give frequency-reuse factors as high as 20, thus greatly expanding the orbit/spectrum resources available for U.S. communications use.

  1. GENERAL: Efficient quantum secure communication with a publicly known key

    NASA Astrophysics Data System (ADS)

    Li, Chun-Yan; Li, Xi-Han; Deng, Fu-Guo; Zhou, Hong-Yu

    2008-07-01

    This paper presents a simple way for an eavesdropper to eavesdrop freely the secret message in the experimental realization of quantum communication protocol proposed by Beige et al (2002 Acta Phys. Pol. A 101 357). Moreover, it introduces an efficient quantum secure communication protocol based on a publicly known key with decoy photons and two biased bases by modifying the original protocol. The total efficiency of this new protocol is double that of the original one. With a low noise quantum channel, this protocol can be used for transmitting a secret message. At present, this protocol is good for generating a private key efficiently.

  2. Doubly infinite separation of quantum information and communication

    NASA Astrophysics Data System (ADS)

    Liu, Zi-Wen; Perry, Christopher; Zhu, Yechao; Koh, Dax Enshan; Aaronson, Scott

    2016-01-01

    We prove the existence of (one-way) communication tasks with a subconstant versus superconstant asymptotic gap, which we call "doubly infinite," between their quantum information and communication complexities. We do so by studying the exclusion game [C. Perry et al., Phys. Rev. Lett. 115, 030504 (2015), 10.1103/PhysRevLett.115.030504] for which there exist instances where the quantum information complexity tends to zero as the size of the input n increases. By showing that the quantum communication complexity of these games scales at least logarithmically in n , we obtain our result. We further show that the established lower bounds and gaps still hold even if we allow a small probability of error. However in this case, the n -qubit quantum message of the zero-error strategy can be compressed polynomially.

  3. Quantum error correction assisted by two-way noisy communication.

    PubMed

    Wang, Zhuo; Yu, Sixia; Fan, Heng; Oh, C H

    2014-01-01

    Pre-shared non-local entanglement dramatically simplifies and improves the performance of quantum error correction via entanglement-assisted quantum error-correcting codes (EAQECCs). However, even considering the noise in quantum communication only, the non-local sharing of a perfectly entangled pair is technically impossible unless additional resources are consumed, such as entanglement distillation, which actually compromises the efficiency of the codes. Here we propose an error-correcting protocol assisted by two-way noisy communication that is more easily realisable: all quantum communication is subjected to general noise and all entanglement is created locally without additional resources consumed. In our protocol the pre-shared noisy entangled pairs are purified simultaneously by the decoding process. For demonstration, we first present an easier implementation of the well-known EAQECC [[4, 1, 3; 1

  4. Quantum error correction assisted by two-way noisy communication

    NASA Astrophysics Data System (ADS)

    Wang, Zhuo; Yu, Sixia; Fan, Heng; Oh, C. H.

    2014-11-01

    Pre-shared non-local entanglement dramatically simplifies and improves the performance of quantum error correction via entanglement-assisted quantum error-correcting codes (EAQECCs). However, even considering the noise in quantum communication only, the non-local sharing of a perfectly entangled pair is technically impossible unless additional resources are consumed, such as entanglement distillation, which actually compromises the efficiency of the codes. Here we propose an error-correcting protocol assisted by two-way noisy communication that is more easily realisable: all quantum communication is subjected to general noise and all entanglement is created locally without additional resources consumed. In our protocol the pre-shared noisy entangled pairs are purified simultaneously by the decoding process. For demonstration, we first present an easier implementation of the well-known EAQECC [[4, 1, 3; 1

  5. Quantum error correction assisted by two-way noisy communication

    PubMed Central

    Wang, Zhuo; Yu, Sixia; Fan, Heng; Oh, C. H.

    2014-01-01

    Pre-shared non-local entanglement dramatically simplifies and improves the performance of quantum error correction via entanglement-assisted quantum error-correcting codes (EAQECCs). However, even considering the noise in quantum communication only, the non-local sharing of a perfectly entangled pair is technically impossible unless additional resources are consumed, such as entanglement distillation, which actually compromises the efficiency of the codes. Here we propose an error-correcting protocol assisted by two-way noisy communication that is more easily realisable: all quantum communication is subjected to general noise and all entanglement is created locally without additional resources consumed. In our protocol the pre-shared noisy entangled pairs are purified simultaneously by the decoding process. For demonstration, we first present an easier implementation of the well-known EAQECC [[4, 1, 3; 1

  6. Classical and quantum communication without a shared reference frame.

    PubMed

    Bartlett, Stephen D; Rudolph, Terry; Spekkens, Robert W

    2003-07-11

    We show that communication without a shared reference frame is possible using entangled states. Both classical and quantum information can be communicated with perfect fidelity without a shared reference frame at a rate that asymptotically approaches one classical bit or one encoded qubit per transmitted qubit. We present an optical scheme to communicate classical bits without a shared reference frame using entangled photon pairs and linear optical Bell state measurements.

  7. Advanced communications payload for mobile applications

    NASA Technical Reports Server (NTRS)

    Ames, S. A.; Kwan, R. K.

    1990-01-01

    An advanced satellite payload is proposed for single hop linking of mobile terminals of all classes as well as Very Small Aperture Terminal's (VSAT's). It relies on an intensive use of communications on-board processing and beam hopping for efficient link design to maximize capacity and a large satellite antenna aperture and high satellite transmitter power to minimize the cost of the ground terminals. Intersatellite links are used to improve the link quality and for high capacity relay. Power budgets are presented for links between the satellite and mobile, VSAT, and hub terminals. Defeating the effects of shadowing and fading requires the use of differentially coherent demodulation, concatenated forward error correction coding, and interleaving, all on a single link basis.

  8. An advanced domestic satellite communications system

    NASA Technical Reports Server (NTRS)

    1980-01-01

    An updated traffic projection for U.S. domestic satellite communications service covering a period of 15 years; mid-1980 to mid-1995 was prepared. This model takes into account expected technology advances and reductions in transmission costs, legislative and regulatory changes permitting increased competition, and rising energy costs which will encourage more extensive substitution of telecommunications for travel. The historical development and current status of satellite systems are discussed as well as the characteristics of follow-on systems. Orbital arc utilization, spacecraft configuration for single shuttle launch, Earth station configuration, and system costs are examined. Areas which require technology development include multiple beam frequency reuse antennas, on-board switching, intersatellite links, and ka-band operation. Packing and deployment schemes for enclosing the satellite within the shuttle orbiter bay must also be devised.

  9. Towards scalable quantum communication and computation: Novel approaches and realizations

    NASA Astrophysics Data System (ADS)

    Jiang, Liang

    Quantum information science involves exploration of fundamental laws of quantum mechanics for information processing tasks. This thesis presents several new approaches towards scalable quantum information processing. First, we consider a hybrid approach to scalable quantum computation, based on an optically connected network of few-qubit quantum registers. Specifically, we develop a novel scheme for scalable quantum computation that is robust against various imperfections. To justify that nitrogen-vacancy (NV) color centers in diamond can be a promising realization of the few-qubit quantum register, we show how to isolate a few proximal nuclear spins from the rest of the environment and use them for the quantum register. We also demonstrate experimentally that the nuclear spin coherence is only weakly perturbed under optical illumination, which allows us to implement quantum logical operations that use the nuclear spins to assist the repetitive-readout of the electronic spin. Using this technique, we demonstrate more than two-fold improvement in signal-to-noise ratio. Apart from direct application to enhance the sensitivity of the NV-based nano-magnetometer, this experiment represents an important step towards the realization of robust quantum information processors using electronic and nuclear spin qubits. We then study realizations of quantum repeaters for long distance quantum communication. Specifically, we develop an efficient scheme for quantum repeaters based on atomic ensembles. We use dynamic programming to optimize various quantum repeater protocols. In addition, we propose a new protocol of quantum repeater with encoding, which efficiently uses local resources (about 100 qubits) to identify and correct errors, to achieve fast one-way quantum communication over long distances. Finally, we explore quantum systems with topological order. Such systems can exhibit remarkable phenomena such as quasiparticles with anyonic statistics and have been proposed as

  10. A universal quantum information processor for scalable quantum communication and networks.

    PubMed

    Yang, Xihua; Xue, Bolin; Zhang, Junxiang; Zhu, Shiyao

    2014-10-15

    Entanglement provides an essential resource for quantum computation, quantum communication, and quantum networks. How to conveniently and efficiently realize the generation, distribution, storage, retrieval, and control of multipartite entanglement is the basic requirement for realistic quantum information processing. Here, we present a theoretical proposal to efficiently and conveniently achieve a universal quantum information processor (QIP) via atomic coherence in an atomic ensemble. The atomic coherence, produced through electromagnetically induced transparency (EIT) in the Λ-type configuration, acts as the QIP and has full functions of quantum beam splitter, quantum frequency converter, quantum entangler, and quantum repeater. By employing EIT-based nondegenerate four-wave mixing processes, the generation, exchange, distribution, and manipulation of light-light, atom-light, and atom-atom multipartite entanglement can be efficiently and flexibly achieved in a deterministic way with only coherent light fields. This method greatly facilitates the operations in quantum information processing, and holds promising applications in realistic scalable quantum communication and quantum networks.

  11. A universal quantum information processor for scalable quantum communication and networks

    PubMed Central

    Yang, Xihua; Xue, Bolin; Zhang, Junxiang; Zhu, Shiyao

    2014-01-01

    Entanglement provides an essential resource for quantum computation, quantum communication, and quantum networks. How to conveniently and efficiently realize the generation, distribution, storage, retrieval, and control of multipartite entanglement is the basic requirement for realistic quantum information processing. Here, we present a theoretical proposal to efficiently and conveniently achieve a universal quantum information processor (QIP) via atomic coherence in an atomic ensemble. The atomic coherence, produced through electromagnetically induced transparency (EIT) in the Λ-type configuration, acts as the QIP and has full functions of quantum beam splitter, quantum frequency converter, quantum entangler, and quantum repeater. By employing EIT-based nondegenerate four-wave mixing processes, the generation, exchange, distribution, and manipulation of light-light, atom-light, and atom-atom multipartite entanglement can be efficiently and flexibly achieved in a deterministic way with only coherent light fields. This method greatly facilitates the operations in quantum information processing, and holds promising applications in realistic scalable quantum communication and quantum networks. PMID:25316514

  12. Error filtration and entanglement purification for quantum communication

    SciTech Connect

    Gisin, N.; Linden, N.; Massar, S.; Popescu, S.

    2005-07-15

    The key realization that led to the emergence of the new field of quantum information processing is that quantum mechanics, the theory that describes microscopic particles, allows the processing of information in fundamentally new ways. But just as in classical information processing, errors occur in quantum information processing, and these have to be corrected. A fundamental breakthrough was the realization that quantum error correction is in fact possible. However, most work so far has not been concerned with technological feasibility, but rather with proving that quantum error correction is possible in principle. Here we describe a method for filtering out errors and entanglement purification which is particularly suitable for quantum communication. Our method is conceptually new, and, crucially, it is easy to implement in a wide variety of physical systems with present-day technology and should therefore be of wide applicability.

  13. Quantum ratchets for quantum communication with optical superlattices

    SciTech Connect

    Romero-Isart, Oriol; Garcia-Ripoll, Juan Jose

    2007-11-15

    We propose to use a quantum ratchet to transport quantum information in a chain of atoms trapped in an optical superlattice. The quantum ratchet is created by a continuous modulation of the optical superlattice which is periodic in time and in space. Though there is zero average force acting on the atoms, we show that indeed the ratchet effect permits atoms on even and odd sites to move along opposite directions. By loading the optical lattice with two-level bosonic atoms, this scheme permits us to perfectly transport a qubit or entangled state imprinted in one or more atoms to any desired position in the lattice. From the quantum computation point of view, the transport is achieved by a smooth concatenation of perfect swap gates. We analyze setups with noninteracting and interacting particles and in the latter case we use the tools of optimal control to design optimal modulations. We also discuss the feasibility of this method in current experiments.

  14. RF Technologies for Advancing Space Communication Infrastructure

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R.; Bibyk, Irene K.; Wintucky, Edwin G.

    2006-01-01

    This paper will address key technologies under development at the NASA Glenn Research Center designed to provide architecture-level impacts. Specifically, we will describe deployable antennas, a new type of phased array antenna and novel power amplifiers. The evaluation of architectural influence can be conducted from two perspectives where said architecture can be analyzed from either the top-down to determine the areas where technology improvements will be most beneficial or from the bottom-up where each technology s performance advancement can affect the overall architecture s performance. This paper will take the latter approach with focus on some technology improvement challenges and address architecture impacts. For example, using data rate as a performance metric, future exploration scenarios are expected to demand data rates possibly exceeding 1 Gbps. To support these advancements in a Mars scenario, as an example, Ka-band and antenna aperture sizes on the order of 10 meters will be required from Mars areostationary platforms. Key technical challenges for a large deployable antenna include maximizing the ratio of deployed-to-packaged volume, minimizing aerial density, maintaining RMS surface accuracy to within 1/20 of a wavelength or better, and developing reflector rigidization techniques. Moreover, the high frequencies and large apertures manifest a new problem for microwave engineers that are familiar to optical communications specialists: pointing. The fine beam widths and long ranges dictate the need for electronic or mechanical feed articulation to compensate for spacecraft attitude control limitations.

  15. Communication theory of quantum systems. Ph.D. Thesis, 1970

    NASA Technical Reports Server (NTRS)

    Yuen, H. P. H.

    1971-01-01

    Communication theory problems incorporating quantum effects for optical-frequency applications are discussed. Under suitable conditions, a unique quantum channel model corresponding to a given classical space-time varying linear random channel is established. A procedure is described by which a proper density-operator representation applicable to any receiver configuration can be constructed directly from the channel output field. Some examples illustrating the application of our methods to the development of optical quantum channel representations are given. Optimizations of communication system performance under different criteria are considered. In particular, certain necessary and sufficient conditions on the optimal detector in M-ary quantum signal detection are derived. Some examples are presented. Parameter estimation and channel capacity are discussed briefly.

  16. Ultrafast and fault-tolerant quantum communication across long distances.

    PubMed

    Muralidharan, Sreraman; Kim, Jungsang; Lütkenhaus, Norbert; Lukin, Mikhail D; Jiang, Liang

    2014-06-27

    Quantum repeaters (QRs) provide a way of enabling long distance quantum communication by establishing entangled qubits between remote locations. In this Letter, we investigate a new approach to QRs in which quantum information can be faithfully transmitted via a noisy channel without the use of long distance teleportation, thus eliminating the need to establish remote entangled links. Our approach makes use of small encoding blocks to fault-tolerantly correct both operational and photon loss errors. We describe a way to optimize the resource requirement for these QRs with the aim of the generation of a secure key. Numerical calculations indicate that the number of quantum memory bits at each repeater station required for the generation of one secure key has favorable polylogarithmic scaling with the distance across which the communication is desired. PMID:25014798

  17. Ultrafast and fault-tolerant quantum communication across long distances.

    PubMed

    Muralidharan, Sreraman; Kim, Jungsang; Lütkenhaus, Norbert; Lukin, Mikhail D; Jiang, Liang

    2014-06-27

    Quantum repeaters (QRs) provide a way of enabling long distance quantum communication by establishing entangled qubits between remote locations. In this Letter, we investigate a new approach to QRs in which quantum information can be faithfully transmitted via a noisy channel without the use of long distance teleportation, thus eliminating the need to establish remote entangled links. Our approach makes use of small encoding blocks to fault-tolerantly correct both operational and photon loss errors. We describe a way to optimize the resource requirement for these QRs with the aim of the generation of a secure key. Numerical calculations indicate that the number of quantum memory bits at each repeater station required for the generation of one secure key has favorable polylogarithmic scaling with the distance across which the communication is desired.

  18. Quantum Secure Direct Communication with Authentication Expansion Using Single Photons

    NASA Astrophysics Data System (ADS)

    Yang, Jing; Wang, Chuan; Zhang, Ru

    2010-11-01

    In this paper we propose two quantum secure direct communication (QSDC) protocols with authentication. The authentication key expansion method is introduced to improve the life of the keys with security. In the first scheme, the third party, called Trent is introduced to authenticate the users that participate in the communication. He sends the polarized photons in blocks to authenticate communication parties Alice and Bob using the authentication keys. In the communication process, polarized single photons are used to serve as the carriers, which transmit the secret messages directly. The second QSDC process with authentication between two parties is also discussed.

  19. Intrinsic quantum correlations of weak coherent states for quantum communication

    SciTech Connect

    Sua Yongmeng; Scanlon, Erin; Beaulieu, Travis; Bollen, Viktor; Lee, Kim Fook

    2011-03-15

    Intrinsic quantum correlations of weak coherent states are observed between two parties through a novel detection scheme, which can be used as a supplement to the existence decoy-state Bennett-Brassard 1984 protocol and the differential phase-shift quantum key distribution (DPS-QKD) protocol. In a proof-of-principle experiment, we generate bipartite correlations of weak coherent states using weak local oscillator fields in two spatially separated balanced homodyne detections. We employ a nonlinearity of postmeasurement method to obtain the bipartite correlations from two single-field interferences at individual homodyne measurements. This scheme is then used to demonstrate bits correlations between two parties over a distance of 10 km through a transmission fiber. We believe that the scheme can add another physical layer of security to these protocols for quantum key distribution.

  20. Spacetime effects on satellite-based quantum communications

    NASA Astrophysics Data System (ADS)

    Bruschi, David Edward; Ralph, Timothy C.; Fuentes, Ivette; Jennewein, Thomas; Razavi, Mohsen

    2014-08-01

    We investigate the consequences of space-time being curved on space-based quantum communication protocols. We analyze tasks that require either the exchange of single photons in a certain entanglement distribution protocol or beams of light in a continuous-variable quantum key distribution scheme. We find that gravity affects the propagation of photons, therefore adding additional noise to the channel for the transmission of information. The effects could be measured with current technology.

  1. Communication: Fully coherent quantum state hopping.

    PubMed

    Martens, Craig C

    2015-10-14

    In this paper, we describe a new and fully coherent stochastic surface hopping method for simulating mixed quantum-classical systems. We illustrate the approach on the simple but unforgiving problem of quantum evolution of a two-state quantum system in the limit of unperturbed pure state dynamics and for dissipative evolution in the presence of both stationary and nonstationary random environments. We formulate our approach in the Liouville representation and describe the density matrix elements by ensembles of trajectories. Population dynamics are represented by stochastic surface hops for trajectories representing diagonal density matrix elements. These are combined with an unconventional coherent stochastic hopping algorithm for trajectories representing off-diagonal quantum coherences. The latter generalizes the binary (0,1) "probability" of a trajectory to be associated with a given state to allow integers that can be negative or greater than unity in magnitude. Unlike existing surface hopping methods, the dynamics of the ensembles are fully entangled, correctly capturing the coherent and nonlocal structure of quantum mechanics.

  2. Communication: Fully coherent quantum state hopping

    SciTech Connect

    Martens, Craig C.

    2015-10-14

    In this paper, we describe a new and fully coherent stochastic surface hopping method for simulating mixed quantum-classical systems. We illustrate the approach on the simple but unforgiving problem of quantum evolution of a two-state quantum system in the limit of unperturbed pure state dynamics and for dissipative evolution in the presence of both stationary and nonstationary random environments. We formulate our approach in the Liouville representation and describe the density matrix elements by ensembles of trajectories. Population dynamics are represented by stochastic surface hops for trajectories representing diagonal density matrix elements. These are combined with an unconventional coherent stochastic hopping algorithm for trajectories representing off-diagonal quantum coherences. The latter generalizes the binary (0,1) “probability” of a trajectory to be associated with a given state to allow integers that can be negative or greater than unity in magnitude. Unlike existing surface hopping methods, the dynamics of the ensembles are fully entangled, correctly capturing the coherent and nonlocal structure of quantum mechanics.

  3. Experimental characterization of Gaussian quantum-communication channels

    SciTech Connect

    Di Guglielmo, James; Hage, Boris; Franzen, Alexander; Schnabel, Roman; Fiurasek, Jaromir

    2007-07-15

    We present a full experimental characterization of continuous-variable quantum-communication channels established by shared entanglement together with local operations and classical communication. The resulting teleportation channel was fully characterized by measuring all elements of the covariance matrix of the shared two-mode squeezed Gaussian state. From the experimental data we determined the lower bound to the quantum channel capacity, the teleportation fidelity of coherent states, and the logarithmic negativity and purity of the shared state. Additionally, a positive secret key rate was obtained for two of the established channels.

  4. Exponential communication gap between weak and strong classical simulations of quantum communication

    NASA Astrophysics Data System (ADS)

    Montina, Alberto

    2013-04-01

    The most trivial way to simulate classically the communication of a quantum state is to transmit the classical description of the quantum state itself. However, this requires an infinite amount of classical communication if the simulation is exact. A more intriguing and potentially less demanding strategy would encode the full information about the quantum state into the probability distribution of the communicated variables so that this information is never sent in each single shot. This kind of simulation is called weak, as opposed to strong simulations, where the quantum state is communicated in individual shots. In this paper, we introduce a bounded-error weak protocol for simulating the communication of an arbitrary number of qubits and a subsequent two-outcome measurement consisting of an arbitrary pure state projector and its complement. This protocol requires an amount of classical communication independent of the number of qubits and proportional to Δ-1, where Δ is the error and a free parameter of the protocol. Conversely, a bounded-error strong protocol requires an amount of classical communication growing exponentially with the number of qubits for a fixed error. Our result improves a previous protocol, based on the Johnson-Lindenstrauss lemma, with communication cost scaling as Δ-2lnΔ-1.

  5. Simple algorithm for computing the communication complexity of quantum communication processes

    NASA Astrophysics Data System (ADS)

    Hansen, A.; Montina, A.; Wolf, S.

    2016-04-01

    A two-party quantum communication process with classical inputs and outcomes can be simulated by replacing the quantum channel with a classical one. The minimal amount of classical communication required to reproduce the statistics of the quantum process is called its communication complexity. In the case of many instances simulated in parallel, the minimal communication cost per instance is called the asymptotic communication complexity. Previously, we reduced the computation of the asymptotic communication complexity to a convex minimization problem. In most cases, the objective function does not have an explicit analytic form, as the function is defined as the maximum over an infinite set of convex functions. Therefore, the overall problem takes the form of a minimax problem and cannot directly be solved by standard optimization methods. In this paper, we introduce a simple algorithm to compute the asymptotic communication complexity. For some special cases with an analytic objective function one can employ available convex-optimization libraries. In the tested cases our method turned out to be notably faster. Finally, using our method we obtain 1.238 bits as a lower bound on the asymptotic communication complexity of a noiseless quantum channel with the capacity of 1 qubit. This improves the previous bound of 1.208 bits.

  6. Natural Mode Entanglement as a Resource for Quantum Communication

    SciTech Connect

    Heaney, Libby; Vedral, Vlatko

    2009-11-13

    Natural particle-number entanglement resides between spatial modes in coherent ultracold atomic gases. However, operations on the modes are restricted by a superselection rule that forbids coherent superpositions of different particle numbers. This seemingly prevents mode entanglement being used as a resource for quantum communication. In this Letter, we demonstrate that mode entanglement of a single massive particle can be used for dense coding and quantum teleportation despite the superselection rule. In particular, we provide schemes where the dense coding linear photonic channel capacity is reached without a shared reservoir and where the full quantum channel capacity is achieved if both parties share a coherent particle reservoir.

  7. Advancing colloidal quantum dot photovoltaic technology

    NASA Astrophysics Data System (ADS)

    Cheng, Yan; Arinze, Ebuka S.; Palmquist, Nathan; Thon, Susanna M.

    2016-06-01

    Colloidal quantum dots (CQDs) are attractive materials for solar cells due to their low cost, ease of fabrication and spectral tunability. Progress in CQD photovoltaic technology over the past decade has resulted in power conversion efficiencies approaching 10%. In this review, we give an overview of this progress, and discuss limiting mechanisms and paths for future improvement in CQD solar cell technology.We briefly summarize nanoparticle synthesis and film processing methods and evaluate the optoelectronic properties of CQD films, including the crucial role that surface ligands play in materials performance. We give an overview of device architecture engineering in CQD solar cells. The compromise between carrier extraction and photon absorption in CQD photovoltaics is analyzed along with different strategies for overcoming this trade-off. We then focus on recent advances in absorption enhancement through innovative device design and the use of nanophotonics. Several light-trapping schemes, which have resulted in large increases in cell photocurrent, are described in detail. In particular, integrating plasmonic elements into CQD devices has emerged as a promising approach to enhance photon absorption through both near-field coupling and far-field scattering effects. We also discuss strategies for overcoming the single junction efficiency limits in CQD solar cells, including tandem architectures, multiple exciton generation and hybrid materials schemes. Finally, we offer a perspective on future directions for the field and the most promising paths for achieving higher device efficiencies.

  8. Quantum-secure covert communication on bosonic channels

    NASA Astrophysics Data System (ADS)

    Bash, Boulat A.; Gheorghe, Andrei H.; Patel, Monika; Habif, Jonathan L.; Goeckel, Dennis; Towsley, Don; Guha, Saikat

    2015-10-01

    Computational encryption, information-theoretic secrecy and quantum cryptography offer progressively stronger security against unauthorized decoding of messages contained in communication transmissions. However, these approaches do not ensure stealth--that the mere presence of message-bearing transmissions be undetectable. We characterize the ultimate limit of how much data can be reliably and covertly communicated over the lossy thermal-noise bosonic channel (which models various practical communication channels). We show that whenever there is some channel noise that cannot in principle be controlled by an otherwise arbitrarily powerful adversary--for example, thermal noise from blackbody radiation--the number of reliably transmissible covert bits is at most proportional to the square root of the number of orthogonal modes (the time-bandwidth product) available in the transmission interval. We demonstrate this in a proof-of-principle experiment. Our result paves the way to realizing communications that are kept covert from an all-powerful quantum adversary.

  9. Quantum-secure covert communication on bosonic channels.

    PubMed

    Bash, Boulat A; Gheorghe, Andrei H; Patel, Monika; Habif, Jonathan L; Goeckel, Dennis; Towsley, Don; Guha, Saikat

    2015-01-01

    Computational encryption, information-theoretic secrecy and quantum cryptography offer progressively stronger security against unauthorized decoding of messages contained in communication transmissions. However, these approaches do not ensure stealth--that the mere presence of message-bearing transmissions be undetectable. We characterize the ultimate limit of how much data can be reliably and covertly communicated over the lossy thermal-noise bosonic channel (which models various practical communication channels). We show that whenever there is some channel noise that cannot in principle be controlled by an otherwise arbitrarily powerful adversary--for example, thermal noise from blackbody radiation--the number of reliably transmissible covert bits is at most proportional to the square root of the number of orthogonal modes (the time-bandwidth product) available in the transmission interval. We demonstrate this in a proof-of-principle experiment. Our result paves the way to realizing communications that are kept covert from an all-powerful quantum adversary. PMID:26478089

  10. Quantum-secure covert communication on bosonic channels

    PubMed Central

    Bash, Boulat A.; Gheorghe, Andrei H.; Patel, Monika; Habif, Jonathan L.; Goeckel, Dennis; Towsley, Don; Guha, Saikat

    2015-01-01

    Computational encryption, information-theoretic secrecy and quantum cryptography offer progressively stronger security against unauthorized decoding of messages contained in communication transmissions. However, these approaches do not ensure stealth—that the mere presence of message-bearing transmissions be undetectable. We characterize the ultimate limit of how much data can be reliably and covertly communicated over the lossy thermal-noise bosonic channel (which models various practical communication channels). We show that whenever there is some channel noise that cannot in principle be controlled by an otherwise arbitrarily powerful adversary—for example, thermal noise from blackbody radiation—the number of reliably transmissible covert bits is at most proportional to the square root of the number of orthogonal modes (the time-bandwidth product) available in the transmission interval. We demonstrate this in a proof-of-principle experiment. Our result paves the way to realizing communications that are kept covert from an all-powerful quantum adversary. PMID:26478089

  11. Quantum-secure covert communication on bosonic channels.

    PubMed

    Bash, Boulat A; Gheorghe, Andrei H; Patel, Monika; Habif, Jonathan L; Goeckel, Dennis; Towsley, Don; Guha, Saikat

    2015-01-01

    Computational encryption, information-theoretic secrecy and quantum cryptography offer progressively stronger security against unauthorized decoding of messages contained in communication transmissions. However, these approaches do not ensure stealth--that the mere presence of message-bearing transmissions be undetectable. We characterize the ultimate limit of how much data can be reliably and covertly communicated over the lossy thermal-noise bosonic channel (which models various practical communication channels). We show that whenever there is some channel noise that cannot in principle be controlled by an otherwise arbitrarily powerful adversary--for example, thermal noise from blackbody radiation--the number of reliably transmissible covert bits is at most proportional to the square root of the number of orthogonal modes (the time-bandwidth product) available in the transmission interval. We demonstrate this in a proof-of-principle experiment. Our result paves the way to realizing communications that are kept covert from an all-powerful quantum adversary.

  12. The Advanced Communication Technology Satellite and ISDN

    NASA Technical Reports Server (NTRS)

    Lowry, Peter A.

    1996-01-01

    This paper depicts the Advanced Communication Technology Satellite (ACTS) system as a global central office switch. The ground portion of the system is the collection of earth stations or T1-VSAT's (T1 very small aperture terminals). The control software for the T1-VSAT's resides in a single CPU. The software consists of two modules, the modem manager and the call manager. The modem manager (MM) controls the RF modem portion of the T1-VSAT. It processes the orderwires from the satellite or from signaling generated by the call manager (CM). The CM controls the Recom Laboratories MSPs by receiving signaling messages from the stacked MSP shelves ro units and sending appropriate setup commands to them. There are two methods used to setup and process calls in the CM; first by dialing up a circuit using a standard telephone handset or, secondly by using an external processor connected to the CPU's second COM port, by sending and receiving signaling orderwires. It is the use of the external processor which permits the ISDN (Integrated Services Digital Network) Signaling Processor to implement ISDN calls. In August 1993, the initial testing of the ISDN Signaling Processor was carried out at ACTS System Test at Lockheed Marietta, Princeton, NJ using the spacecraft in its test configuration on the ground.

  13. Comment on: Supervisory Asymmetric Deterministic Secure Quantum Communication

    NASA Astrophysics Data System (ADS)

    Kao, Shih-Hung; Tsai, Chia-Wei; Hwang, Tzonelih

    2012-12-01

    In 2010, Xiu et al. (Optics Communications 284:2065-2069, 2011) proposed several applications based on a new secure four-site distribution scheme using χ-type entangled states. This paper points out that one of these applications, namely, supervisory asymmetric deterministic secure quantum communication, is subject to an information leakage problem, in which the receiver can extract two bits of a three-bit secret message without the supervisor's permission. An enhanced protocol is proposed to resolve this problem.

  14. Protocol for direct counterfactual quantum communication.

    PubMed

    Salih, Hatim; Li, Zheng-Hong; Al-Amri, M; Zubairy, M Suhail

    2013-04-26

    It has long been assumed in physics that for information to travel between two parties in empty space, "Alice" and "Bob," physical particles have to travel between them. Here, using the "chained" quantum Zeno effect, we show how, in the ideal asymptotic limit, information can be transferred between Alice and Bob without any physical particles traveling between them.

  15. Nonlocal Quantum Information Transfer Without Superluminal Signalling and Communication

    NASA Astrophysics Data System (ADS)

    Walleczek, Jan; Grössing, Gerhard

    2016-09-01

    It is a frequent assumption that—via superluminal information transfers—superluminal signals capable of enabling communication are necessarily exchanged in any quantum theory that posits hidden superluminal influences. However, does the presence of hidden superluminal influences automatically imply superluminal signalling and communication? The non-signalling theorem mediates the apparent conflict between quantum mechanics and the theory of special relativity. However, as a `no-go' theorem there exist two opposing interpretations of the non-signalling constraint: foundational and operational. Concerning Bell's theorem, we argue that Bell employed both interpretations, and that he finally adopted the operational position which is associated often with ontological quantum theory, e.g., de Broglie-Bohm theory. This position we refer to as "effective non-signalling". By contrast, associated with orthodox quantum mechanics is the foundational position referred to here as "axiomatic non-signalling". In search of a decisive communication-theoretic criterion for differentiating between "axiomatic" and "effective" non-signalling, we employ the operational framework offered by Shannon's mathematical theory of communication, whereby we distinguish between Shannon signals and non-Shannon signals. We find that an effective non-signalling theorem represents two sub-theorems: (1) Non-transfer-control (NTC) theorem, and (2) Non-signification-control (NSC) theorem. Employing NTC and NSC theorems, we report that effective, instead of axiomatic, non-signalling is entirely sufficient for prohibiting nonlocal communication. Effective non-signalling prevents the instantaneous, i.e., superluminal, transfer of message-encoded information through the controlled use—by a sender-receiver pair —of informationally-correlated detection events, e.g., in EPR-type experiments. An effective non-signalling theorem allows for nonlocal quantum information transfer yet—at the same time

  16. Nonlocal Quantum Information Transfer Without Superluminal Signalling and Communication

    NASA Astrophysics Data System (ADS)

    Walleczek, Jan; Grössing, Gerhard

    2016-01-01

    It is a frequent assumption that—via superluminal information transfers—superluminal signals capable of enabling communication are necessarily exchanged in any quantum theory that posits hidden superluminal influences. However, does the presence of hidden superluminal influences automatically imply superluminal signalling and communication? The non-signalling theorem mediates the apparent conflict between quantum mechanics and the theory of special relativity. However, as a `no-go' theorem there exist two opposing interpretations of the non-signalling constraint: foundational and operational. Concerning Bell's theorem, we argue that Bell employed both interpretations, and that he finally adopted the operational position which is associated often with ontological quantum theory, e.g., de Broglie-Bohm theory. This position we refer to as "effective non-signalling". By contrast, associated with orthodox quantum mechanics is the foundational position referred to here as "axiomatic non-signalling". In search of a decisive communication-theoretic criterion for differentiating between "axiomatic" and "effective" non-signalling, we employ the operational framework offered by Shannon's mathematical theory of communication, whereby we distinguish between Shannon signals and non-Shannon signals. We find that an effective non-signalling theorem represents two sub-theorems: (1) Non-transfer-control (NTC) theorem, and (2) Non-signification-control (NSC) theorem. Employing NTC and NSC theorems, we report that effective, instead of axiomatic, non-signalling is entirely sufficient for prohibiting nonlocal communication. Effective non-signalling prevents the instantaneous, i.e., superluminal, transfer of message-encoded information through the controlled use—by a sender-receiver pair —of informationally-correlated detection events, e.g., in EPR-type experiments. An effective non-signalling theorem allows for nonlocal quantum information transfer yet—at the same time

  17. Advancing Instructional Communication: Integrating a Biosocial Approach

    ERIC Educational Resources Information Center

    Horan, Sean M.; Afifi, Tamara D.

    2014-01-01

    Celebrating 100 years of the National Communication Association necessitates that, as we commemorate our past, we also look toward our future. As part of a larger conversation about the future of instructional communication, this essay reinvestigates the importance of integrating biosocial approaches into instructional communication research. In…

  18. Advances in terahertz communications accelerated by photonics

    NASA Astrophysics Data System (ADS)

    Nagatsuma, Tadao; Ducournau, Guillaume; Renaud, Cyril C.

    2016-06-01

    Almost 15 years have passed since the initial demonstrations of terahertz (THz) wireless communications were made using both pulsed and continuous waves. THz technologies are attracting great interest and are expected to meet the ever-increasing demand for high-capacity wireless communications. Here, we review the latest trends in THz communications research, focusing on how photonics technologies have played a key role in the development of first-age THz communication systems. We also provide a comparison with other competitive technologies, such as THz transceivers enabled by electronic devices as well as free-space lightwave communications.

  19. Relativistic quantum channel of communication through field quanta

    SciTech Connect

    Cliche, M.; Kempf, A.

    2010-01-15

    Setups in which a system Alice emits field quanta that a system Bob receives are prototypical for wireless communication and have been extensively studied. In the most basic setup, Alice and Bob are modeled as Unruh-DeWitt detectors for scalar quanta, and the only noise in their communication is due to quantum fluctuations. For this basic setup, we construct the corresponding information-theoretic quantum channel. We calculate the classical channel capacity as a function of the spacetime separation, and we confirm that the classical as well as the quantum channel capacity are strictly zero for spacelike separations. We show that this channel can be used to entangle Alice and Bob instantaneously. Alice and Bob are shown to extract this entanglement from the vacuum through a Casimir-Polder effect.

  20. Advanced Shipboard Communications Demonstrations with ACTS

    NASA Technical Reports Server (NTRS)

    Axford, Roy A.; Jedrey, Thomas C.; Rupar, Michael A.

    2000-01-01

    For ships at sea. satellites provide the only option for high data rate (HDR), long haul communications. Furthermore the demand for HDR satellite communications (SATCOM) for military and commercial ships. and other offshore platforms is increasing. Presently the bulk of this maritime HDR SATCOM connectivity is provided via C-band and X-band. However, the shipboard antenna sizes required to achieve a data rate of, say T 1 (1.544 Mbps) with present C-/X-band SATCOM systems range from seven to ten feet in diameter. This limits the classes of ships to which HDR services can be provided to those which are large enough to accommodate the massive antennas. With its high powered K/Ka-band spot beams, the National Aeronautics and Space Administration's (NASA) Advanced Communications Technology Satellite (ACTS) was able to provide T I and higher rate services to ships at sea using much smaller shipboard antennas. This paper discusses three shipboard HDR SATCOM demonstrations that were conducted with ACTS between 1996 and 1998. The first demonstration involved a 2 Mbps link provided to the seismic survey ship MN Geco Diamond equipped with a 16-inch wide, 4.5-inch tall, mechanically steered slotted waveguide array antenna developed by the Jet Propulsion Laboratory. In this February 1996 demonstration ACTS allowed supercomputers ashore to process Geco Diamond's voluminous oceanographic seismic data in near real time. This capability allowed the ship to adjust its search parameters on a daily basis based on feedback from the processed data, thereby greatly increasing survey efficiency. The second demonstration was conducted on the US Navy cruiser USS Princeton (CG 59) with the same antenna used on Geco Diamond. Princeton conducted a six-month (January-July 1997) Western Hemisphere solo deployment during which time T1 connectivity via ACTS provided the ship with a range of valuable tools for operational, administrative and quality-of-life tasks. In one instance, video

  1. Quantum Sensing and Communications Being Developed for Nanotechnology

    NASA Technical Reports Server (NTRS)

    Nguyen, Quang-Viet; Seibert, Marc A.

    2003-01-01

    An interdisciplinary quantum communications and sensing research effort has been underway at the NASA Glenn Research Center since the summer of 2000. Researchers in the Communications Technology, Instrumentation and Controls, and Propulsion and Turbomachinery Divisions have been working together to study and develop techniques that use the principle of quantum entanglement (QE). This work is supported principally by the Nanotechnology Base R&T program at Glenn. As applied to communications and sensing, QE is an emerging technology that holds promise as a new and innovative way to communicate faster and farther, and to sense, measure, and image environmental properties in ways that are not possible with existing technology. Quantum entangled photons are "inseparable" as described by a wave function formalism. For two entangled photons, the term "inseparable" means that one cannot describe one photon without completely describing the other. This inseparability gives rise to what appears as "spooky," or nonintuitive, behavior because of the quantum nature of the process. For example, two entangled photons of lower energy can be created simultaneously from a single photon of higher energy in a process called spontaneous parametric down-conversion. Our research is focused on the use of polarization-entangled photons generated by passing a high-energy (blue) photon through a nonlinear beta barium borate crystal to generate two red photons that have orthogonal, but entangled, polarization states. Although the actual polarization state of any one photon is not known until it is measured, the act of measuring the polarization of one photon completely determines the polarization state of its twin because of entanglement. This unique relationship between the photons provides extra information about the system. For example, entanglement makes it easy to distinguish entangled photons from other photons impinging on a detector. For many other applications, ranging from quantum

  2. Simultaneous classical communication and quantum key distribution using continuous variables

    DOE PAGES

    Qi, Bing

    2016-10-26

    Currently, classical optical communication systems employing strong laser pulses and quantum key distribution (QKD) systems working at single-photon levels are very different communication modalities. Dedicated devices are commonly required to implement QKD. In this paper, we propose a scheme which allows classical communication and QKD to be implemented simultaneously using the same communication infrastructure. More specially, we propose a coherent communication scheme where both the bits for classical communication and the Gaussian distributed random numbers for QKD are encoded on the same weak coherent pulse and decoded by the same coherent receiver. Simulation results based on practical system parameters showmore » that both deterministic classical communication with a bit error rate of 10–9 and secure key distribution could be achieved over tens of kilometers of single-mode fibers. It is conceivable that in the future coherent optical communication network, QKD will be operated in the background of classical communication at a minimal cost.« less

  3. Advances in MMIC technology for communications satellites

    NASA Technical Reports Server (NTRS)

    Leonard, Regis F.

    1992-01-01

    This paper discusses NASA Lewis Research Center's program for development of monolithic microwave integrated circuits (MMIC) for application in space communications. Emphasis will be on the improved performance in power amplifiers and low noise receivers which has been made possible by the development of new semiconductor materials and devices. Possible applications of high temperature superconductivity for space communications will also be presented.

  4. Quantum secure communication using a multi-photon tolerant protocol

    NASA Astrophysics Data System (ADS)

    El Rifai, Mayssaa; Verma, Pramode K.

    2015-03-01

    This paper proposes a quantum secure communication protocol using multiple photons to represent each bit of a message to be shared. The multi-photon tolerant approach to quantum cryptography provides a quantum level security while using more than a single photon per transmission. The protocol proposed is a multi-stage protocol; an explanation of its operation and implementation are provided. The multi-stage protocol is based on the use of unitary transformations known only to Alice and Bob. This paper studies the security aspects of the multi-stage protocol by assessing its vulnerability to different attacks. It is well known that as the number of photons increases, the level of vulnerability of the multi-stage protocol increases. This paper sets a limit on the number of photons that can be used while keeping the multi-stage protocol a multi-photon tolerant quantum secure method for communication. The analysis of the number of photons to be used is based on the probability of success of a Helstrom discrimination done by an eavesdropper on the channel. Limiting the number of photons up to certain threshold per stage makes it impossible for an eavesdropper to decipher the message sent over the channel. The proposed protocol obviates the disadvantages associated with single photon implementations, such as limited data rates and distances along with the need to have no more than a single photon per time slot. The multi-stage protocol is a step toward direct quantum communication rather than quantum key distribution associated with single photon approaches.

  5. Basics of perfect communication through quantum networks

    SciTech Connect

    Kay, Alastair

    2011-08-15

    Perfect transfer of a quantum state through a one-dimensional chain is now well understood, allowing one not only to decide whether a fixed Hamiltonian achieves perfect transfer but to design a suitable one. We are particularly interested in being able to design, or understand the limitations imposed upon, Hamiltonians subject to various naturally arising constraints such as a limited coupling topology with low connectivity (specified by a graph) and type of interaction. In this paper, we characterize the necessary and sufficient conditions for transfer through a network and describe some natural consequences such as the impossibility of routing between many different recipients for a large class of Hamiltonians and the limitations on transfer rate. We also consider some of the trade-offs that arise in uniformly coupled networks (both Heisenberg and XX models) between transfer distance and the size of the network as a consequence of the derived conditions.

  6. Partitioned-Interval Quantum Optical Communications Receiver

    NASA Technical Reports Server (NTRS)

    Vilnrotter, Victor A.

    2013-01-01

    The proposed quantum receiver in this innovation partitions each binary signal interval into two unequal segments: a short "pre-measurement" segment in the beginning of the symbol interval used to make an initial guess with better probability than 50/50 guessing, and a much longer segment used to make the high-sensitivity signal detection via field-cancellation and photon-counting detection. It was found that by assigning as little as 10% of the total signal energy to the pre-measurement segment, the initial 50/50 guess can be improved to about 70/30, using the best available measurements such as classical coherent or "optimized Kennedy" detection.

  7. Advancements in the Field of Quantum Dots

    NASA Astrophysics Data System (ADS)

    Mishra, Sambeet; Tripathy, Pratyasha; Sinha, Swami Prasad.

    2012-08-01

    Quantum dots are defined as very small semiconductor crystals of size varying from nanometer scale to a few micron i.e. so small that they are considered dimensionless and are capable of showing many chemical properties by virtue of which they tend to be lead at one minute and gold at the second minute.Quantum dots house the electrons just the way the electrons would have been present in an atom, by applying a voltage. And therefore they are very judiciously given the name of being called as the artificial atoms. This application of voltage may also lead to the modification of the chemical nature of the material anytime it is desired, resulting in lead at one minute to gold at the other minute. But this method is quite beyond our reach. A quantum dot is basically a semiconductor of very tiny size and this special phenomenon of quantum dot, causes the band of energies to change into discrete energy levels. Band gaps and the related energy depend on the relationship between the size of the crystal and the exciton radius. The height and energy between different energy levels varies inversely with the size of the quantum dot. The smaller the quantum dot, the higher is the energy possessed by it.There are many applications of the quantum dots e.g. they are very wisely applied to:Light emitting diodes: LEDs eg. White LEDs, Photovoltaic devices: solar cells, Memory elements, Biology : =biosensors, imaging, Lasers, Quantum computation, Flat-panel displays, Photodetectors, Life sciences and so on and so forth.The nanometer sized particles are able to display any chosen colour in the entire ultraviolet visible spectrum through a small change in their size or composition.

  8. Quantum communication using a multiqubit entangled channel

    SciTech Connect

    Ghose, Shohini; Hamel, Angele

    2015-12-31

    We describe a protocol in which two senders each teleport a qubit to a receiver using a multiqubit entangled state. The multiqubit channel used for teleportation is genuinely 4-qubit entangled and is not equivalent to a product of maximally entangled Bell pairs under local unitary operations. We discuss a scenario in which both senders must participate for the qubits to be successfully teleported. Such an all-or-nothing scheme cannot be implemented with standard two-qubit entangled Bell pairs and can be useful for different communication and computing tasks.

  9. Quantum communication using a multiqubit entangled channel

    NASA Astrophysics Data System (ADS)

    Ghose, Shohini; Hamel, Angele

    2015-12-01

    We describe a protocol in which two senders each teleport a qubit to a receiver using a multiqubit entangled state. The multiqubit channel used for teleportation is genuinely 4-qubit entangled and is not equivalent to a product of maximally entangled Bell pairs under local unitary operations. We discuss a scenario in which both senders must participate for the qubits to be successfully teleported. Such an all-or-nothing scheme cannot be implemented with standard two-qubit entangled Bell pairs and can be useful for different communication and computing tasks.

  10. Impact of turbulence in long range quantum and classical communications.

    PubMed

    Capraro, Ivan; Tomaello, Andrea; Dall'Arche, Alberto; Gerlin, Francesca; Ursin, Ruper; Vallone, Giuseppe; Villoresi, Paolo

    2012-11-16

    The study of the free-space distribution of quantum correlations is necessary for any future application of quantum and classical communication aiming to connect two remote locations. Here we study the propagation of a coherent laser beam over 143 km (between Tenerife and La Palma Islands of the Canary archipelagos). By attenuating the beam we also studied the propagation at the single photon level. We investigated the statistic of arrival of the incoming photons and the scintillation of the beam. From the analysis of the data, we propose the exploitation of turbulence to improve the signal to noise ratio of the signal.

  11. An Online Banking System Based on Quantum Cryptography Communication

    NASA Astrophysics Data System (ADS)

    Zhou, Ri-gui; Li, Wei; Huan, Tian-tian; Shen, Chen-yi; Li, Hai-sheng

    2014-07-01

    In this paper, an online banking system has been built. Based on quantum cryptography communication, this system is proved unconditional secure. Two sets of GHZ states are applied, which can ensure the safety of purchase and payment, respectively. In another word, three trading participants in each triplet state group form an interdependent and interactive relationship. In the meantime, trading authorization and blind signature is introduced by means of controllable quantum teleportation. Thus, an effective monitor is practiced on the premise that the privacy of trading partners is guaranteed. If there is a dispute or deceptive behavior, the system will find out the deceiver immediately according to the relationship mentioned above.

  12. Free-space communication based on quantum cascade laser

    NASA Astrophysics Data System (ADS)

    Chuanwei, Liu; Shenqiang, Zhai; Jinchuan, Zhang; Yuhong, Zhou; Zhiwei, Jia; Fengqi, Liu; Zhanguo, Wang

    2015-09-01

    A free-space communication based on a mid-infrared quantum cascade laser (QCL) is presented. A room-temperature continuous-wave distributed-feedback (DFB) QCL combined with a mid-infrared detector comprise the basic unit of the communication system. Sinusoidal signals at a highest frequency of 40 MHz and modulated video signals with a carrier frequency of 30 MHz were successfully transmitted with this experimental setup. Our research has provided a proof-of-concept demonstration of space optical communication application with QCL. The highest operation frequency of our setup was determined by the circuit-limited modulation bandwidth. A high performance communication system can be obtained with improved modulation circuit system. Project supported by the State Key Development Program for Basic Research of China (Nos. 2013CB632801, 2013CB632803) and the National Natural Science Foundation of China (Nos. 61435014, 61306058, 61274094).

  13. Communication Tasks with Infinite Quantum-Classical Separation.

    PubMed

    Perry, Christopher; Jain, Rahul; Oppenheim, Jonathan

    2015-07-17

    Quantum resources can be more powerful than classical resources-a quantum computer can solve certain problems exponentially faster than a classical computer, and computing a function of two parties' inputs can be done with exponentially less communication with quantum messages than with classical ones. Here we consider a task between two players, Alice and Bob where quantum resources are infinitely more powerful than their classical counterpart. Alice is given a string of length n, and Bob's task is to exclude certain combinations of bits that Alice might have. If Alice must send classical messages, then she must reveal nearly n bits of information to Bob, but if she is allowed to send quantum bits, the amount of information she must reveal goes to zero with increasing n. Next, we consider a version of the task where the parties may have access to entanglement. With this assistance, Alice only needs to send a constant number of bits, while without entanglement, the number of bits Alice must send grows linearly with n. The task is related to the Pusey-Barrett-Rudolph theorem which arises in the context of the foundations of quantum theory. PMID:26230777

  14. Communication Tasks with Infinite Quantum-Classical Separation.

    PubMed

    Perry, Christopher; Jain, Rahul; Oppenheim, Jonathan

    2015-07-17

    Quantum resources can be more powerful than classical resources-a quantum computer can solve certain problems exponentially faster than a classical computer, and computing a function of two parties' inputs can be done with exponentially less communication with quantum messages than with classical ones. Here we consider a task between two players, Alice and Bob where quantum resources are infinitely more powerful than their classical counterpart. Alice is given a string of length n, and Bob's task is to exclude certain combinations of bits that Alice might have. If Alice must send classical messages, then she must reveal nearly n bits of information to Bob, but if she is allowed to send quantum bits, the amount of information she must reveal goes to zero with increasing n. Next, we consider a version of the task where the parties may have access to entanglement. With this assistance, Alice only needs to send a constant number of bits, while without entanglement, the number of bits Alice must send grows linearly with n. The task is related to the Pusey-Barrett-Rudolph theorem which arises in the context of the foundations of quantum theory.

  15. Palliative communications: addressing chemotherapy in patients with advanced cancer.

    PubMed

    Kadakia, K C; Moynihan, T J; Smith, T J; Loprinzi, C L

    2012-04-01

    Patients with advanced cancers often endure chemotherapy late in their disease course leading to unnecessary adverse effects, loss of quality of life, and delay in hospice referral. Compassionate and honest communication about the use of chemotherapy can facilitate better patient care. This manuscript will explore communication issues regarding palliative-intent chemotherapy.

  16. Advanced technology for space communications, tracking, and robotic sensors

    NASA Technical Reports Server (NTRS)

    Krishen, Kumar

    1989-01-01

    Technological advancements in tracking, communications, and robotic vision sensors are reviewed. The development of communications systems for multiple access, broadband, high data rate, and efficient operation is discussed. Consideration is given to the Tracking and Data Relay Satellite systems, GPS, and communications and tracking systems for the Space Shuttle and the Space Station. The use of television, laser, and microwave sensors for robotics and technology for autonomous rendezvous and docking operations are examined.

  17. Satellite quantum communication towards GEO distances

    NASA Astrophysics Data System (ADS)

    Vallone, Giuseppe; Dequal, Daniele; Tomasin, M.; Schiavon, M.; Vedovato, F.; Bacco, Davide; Gaiarin, Simone; Bianco, Giuseppe; Luceri, Vincenza; Villoresi, Paolo

    2016-04-01

    We report on several experiments of single photon transmission from space to ground realized at the Matera Laser Ranging Observatory (MLRO) of the Italian Space Agency in Matera (Italy). We simulated a source of coherent pulses attenuated to the single photon level by exploiting laser ranging satellites equipped with corner-cube retroreflectors (CCRs). By such technique we report QC with qubits encoded in polarization from low-Earth-orbit (LEO) at distance up to 2500km from the ground station, achieving a low quantum bit error ratio (QBER) for different satellites. The same technique is exploited to demonstrate single photon exchange with a medium-Earth-orbit (MEO) satellite, Lageos-2 at more than 7000 km of distance from the MLRO station. In both experiments the temporal jitter of the received counts is of the order of 1.2ns FWHM due to the intrinsic jitter of the single photon detectors. In order to improve the discrimination of signal from the background and reaching distances corresponding to GEO satellites, we improved the detection scheme by using fast single photon detectors with 40 ps FWHM jitter. We report improved single photon detection jitter from Beacon-C and Ajisai, obtaining 340 ps FWHM in the best case.

  18. Fast quantum communication in linear networks

    NASA Astrophysics Data System (ADS)

    Jacobs, Kurt; Wu, Rebing; Wang, Xiaoting; Ashhab, Sahel; Chen, Qi-Ming; Rabitz, Herschel

    2016-05-01

    Here we consider the speed at which quantum information can be transferred between the nodes of a linear network. Because such nodes are linear oscillators, this speed is also important in the cooling and state preparation of mechanical oscillators, as well as in frequency conversion. We show that if there is no restriction on the size of the linear coupling between two oscillators, then there exist control protocols that will swap their respective states with high fidelity within a time much shorter than a single oscillation period. Standard gradient search methods fail to find these fast protocols. We were able to do so by augmenting standard search methods with a path-tracing technique, demonstrating that this technique has remarkable power to solve time-optimal control problems, as well as confirming the highly challenging nature of these problems. As a further demonstration of the power of path tracing, first introduced by Moore Tibbets et al. (Phys. Rev. A, 86 (2012) 062309), we apply it to the generation of entanglement in a linear network.

  19. Satellite quantum communication towards GEO distances

    NASA Astrophysics Data System (ADS)

    Vallone, Giuseppe; Dequal, Daniele; Tomasin, M.; Schiavon, M.; Vedovato, F.; Bacco, Davide; Gaiarin, Simone; Bianco, Giuseppe; Luceri, Vincenza; Villoresi, Paolo

    2016-04-01

    We report on several experiments of single photon transmission from space to ground realized at the Matera Laser Ranging Observatory (MLRO) of the Italian Space Agency in Matera (Italy). We simulated a source of coherent pulses attenuated to the single photon level by exploiting laser ranging satellites equipped with corner-cube retroreflectors (CCRs). By such technique we report QC with qubits encoded in polarization from low-Earth-orbit (LEO) at distance up to 2500km from the ground station, achieving a low quantum bit error ratio (QBER) for different satellites. The same technique is exploited to demonstrate single photon exchange with a medium-Earth-orbit (MEO) satellite, Lageos-2 at more than 7000 km of distance from the MLRO station. In both experiments the temporal jitter of the received counts is of the order of 1.2ns FWHM due to the intrinsic jitter of the single photon detectors. In order to improve the discrimination of signal from the background and reaching distances corresponding to GEO satellites, we improved the detection scheme by using fast single photon detectors with 40 ps FWHM jitter. We report improved single photon detection jitter from Beacon-C and Ajisai, obtaining 340 ps FWHM in the best case.

  20. Virtual Learning Environment for Interactive Engagement with Advanced Quantum Mechanics

    NASA Astrophysics Data System (ADS)

    Pedersen, Mads Kock; Skyum, Birk; Heck, Robert; Müller, Romain; Bason, Mark; Lieberoth, Andreas; Sherson, Jacob F.

    2016-06-01

    A virtual learning environment can engage university students in the learning process in ways that the traditional lectures and lab formats cannot. We present our virtual learning environment StudentResearcher, which incorporates simulations, multiple-choice quizzes, video lectures, and gamification into a learning path for quantum mechanics at the advanced university level. StudentResearcher is built upon the experiences gathered from workshops with the citizen science game Quantum Moves at the high-school and university level, where the games were used extensively to illustrate the basic concepts of quantum mechanics. The first test of this new virtual learning environment was a 2014 course in advanced quantum mechanics at Aarhus University with 47 enrolled students. We found increased learning for the students who were more active on the platform independent of their previous performances.

  1. Aerospace laser communications technology as enabler for worldwide quantum key distribution

    NASA Astrophysics Data System (ADS)

    Moll, Florian; Weinfurter, Harald; Rau, Markus; Schmidt, Christopher; Melén, Gwen; Vogl, Tobias; Nauerth, Sebastian; Fuchs, Christian

    2016-04-01

    A worldwide growing interest in fast and secure data communications pushes technology development along two lines. While fast communications can be realized using laser communications in fiber and free-space, inherently secure communications can be achieved using quantum key distribution (QKD). By combining both technologies in a single device, many synergies can be exploited, therefore reducing size, weight and power of future systems. In recent experiments we demonstrated quantum communications over large distances as well as between an aircraft and a ground station which proved the feasibility of QKD between moving partners. Satellites thus may be used as trusted nodes in combination with QKD receiver stations on ground, thereby enabling fast and secure communications on a global scale. We discuss the previous experiment with emphasis on necessary developments to be done and corresponding ongoing research work of German Aerospace Center (DLR) and Ludwig Maximilians University Munich (LMU). DLR is performing research on satellite and ground terminals for the high-rate laser communication component, which are enabling technologies for the QKD link. We describe the concept and hardware of three generations of OSIRIS (Optical High Speed Infrared Link System) laser communication terminals for low Earth orbiting satellites. The first type applies laser beam pointing solely based on classical satellite control, the second uses an optical feedback to the satellite bus and the third, currently being in design phase, comprises of a special coarse pointing assembly to control beam direction independent of satellite orientation. Ongoing work also targets optical terminals for CubeSats. A further increase of beam pointing accuracy can be achieved with a fine pointing assembly. Two ground stations will be available for future testing, an advanced stationary ground station and a transportable ground station. In parallel the LMU QKD source size will be reduced by more than an

  2. Quantum Authencryption with Two-Photon Entangled States for Off-Line Communicants

    NASA Astrophysics Data System (ADS)

    Ye, Tian-Yu

    2016-02-01

    In this paper, a quantum authencryption protocol is proposed by using the two-photon entangled states as the quantum resource. Two communicants Alice and Bob share two private keys in advance, which determine the generation of two-photon entangled states. The sender Alice sends the two-photon entangled state sequence encoded with her classical bits to the receiver Bob in the manner of one-step quantum transmission. Upon receiving the encoded quantum state sequence, Bob decodes out Alice's classical bits with the two-photon joint measurements and authenticates the integrity of Alice's secret with the help of one-way hash function. The proposed protocol only uses the one-step quantum transmission and needs neither a public discussion nor a trusted third party. As a result, the proposed protocol can be adapted to the case where the receiver is off-line, such as the quantum E-mail systems. Moreover, the proposed protocol provides the message authentication to one bit level with the help of one-way hash function and has an information-theoretical efficiency equal to 100 %.

  3. Experimental bit commitment based on quantum communication and special relativity.

    PubMed

    Lunghi, T; Kaniewski, J; Bussières, F; Houlmann, R; Tomamichel, M; Kent, A; Gisin, N; Wehner, S; Zbinden, H

    2013-11-01

    Bit commitment is a fundamental cryptographic primitive in which Bob wishes to commit a secret bit to Alice. Perfectly secure bit commitment between two mistrustful parties is impossible through asynchronous exchange of quantum information. Perfect security is however possible when Alice and Bob split into several agents exchanging classical and quantum information at times and locations suitably chosen to satisfy specific relativistic constraints. Here we report on an implementation of a bit commitment protocol using quantum communication and special relativity. Our protocol is based on [A. Kent, Phys. Rev. Lett. 109, 130501 (2012)] and has the advantage that it is practically feasible with arbitrary large separations between the agents in order to maximize the commitment time. By positioning agents in Geneva and Singapore, we obtain a commitment time of 15 ms. A security analysis considering experimental imperfections and finite statistics is presented.

  4. Communication at the quantum speed limit along a spin chain

    SciTech Connect

    Murphy, Michael; Montangero, Simone; Giovannetti, Vittorio; Calarco, Tommaso

    2010-08-15

    Spin chains have long been considered as candidates for quantum channels to facilitate quantum communication. We consider the transfer of a single excitation along a spin-1/2 chain governed by Heisenberg-type interactions. We build on the work of Balachandran and Gong [V. Balachandran and J. Gong, Phys. Rev. A 77, 012303 (2008)] and show that by applying optimal control to an external parabolic magnetic field, one can drastically increase the propagation rate by two orders of magnitude. In particular, we show that the theoretical maximum propagation rate can be reached, where the propagation of the excitation takes the form of a dispersed wave. We conclude that optimal control is not only a useful tool for experimental application, but also for theoretical inquiry into the physical limits and dynamics of many-body quantum systems.

  5. Experimental bit commitment based on quantum communication and special relativity.

    PubMed

    Lunghi, T; Kaniewski, J; Bussières, F; Houlmann, R; Tomamichel, M; Kent, A; Gisin, N; Wehner, S; Zbinden, H

    2013-11-01

    Bit commitment is a fundamental cryptographic primitive in which Bob wishes to commit a secret bit to Alice. Perfectly secure bit commitment between two mistrustful parties is impossible through asynchronous exchange of quantum information. Perfect security is however possible when Alice and Bob split into several agents exchanging classical and quantum information at times and locations suitably chosen to satisfy specific relativistic constraints. Here we report on an implementation of a bit commitment protocol using quantum communication and special relativity. Our protocol is based on [A. Kent, Phys. Rev. Lett. 109, 130501 (2012)] and has the advantage that it is practically feasible with arbitrary large separations between the agents in order to maximize the commitment time. By positioning agents in Geneva and Singapore, we obtain a commitment time of 15 ms. A security analysis considering experimental imperfections and finite statistics is presented. PMID:24237497

  6. Advanced high capacity domestic satellite communications system

    NASA Astrophysics Data System (ADS)

    Iso, Akio; Kohiyama, Kenji; Odate, Hitoshi; Ishida, Noriaki

    This paper describes a concept of multibeam high capacity transmission possible with a 30/20 GHz and 50/40 GHz domestic satellite communication system. The relationship between satellite antenna pointing accuracy and multi-beam antenna interference, as well as the relationship between satellite antenna pointing accuracy and multi-satellite interference are looked at. The ultra high capacity domestic satellite communication system will have multi-beam antennas with a 76.0 dB at both 20 GHz and 40 GHz. These antennas will provide 4950 beams that approximately correspond to the number of end office of the Japanese telephone network, and have a pointing accuracy of 0.005 degrees. This system will be equipped with 9900 30/20 GHz and 50/40 GHz transponder channels with bit rates of 800 Mbps. Its capacity will be 119 Tbps through use of 15 large communication satellite platforms.

  7. Quantum cryptography for secure free-space communications

    SciTech Connect

    Hughes, R.J.; Buttler, W.T.; Kwiat, P.G.; Lamoreaux, S.K.; Luther, G.G.; Morgan, G.L.; Nordholt, J.E.; Peterson, C.G.

    1999-03-01

    The secure distribution of the secret random bit sequences known as key material, is an essential precursor to their use for the encryption and decryption of confidential communications. Quantum cryptography is a new technique for secure key distribution with single-photon transmissions: Heisenberg`s uncertainty principle ensures that an adversary can neither successfully tap the key transmissions, nor evade detection (eavesdropping raises the key error rate above a threshold value). The authors have developed experimental quantum cryptography systems based on the transmission of non-orthogonal photon polarization states to generate shared key material over line-of-sight optical links. Key material is built up using the transmission of a single-photon per bit of an initial secret random sequence. A quantum-mechanically random subset of this sequence is identified, becoming the key material after a data reconciliation stage with the sender. The authors have developed and tested a free-space quantum key distribution (QKD) system over an outdoor optical path of {approximately}1 km at Los Alamos National Laboratory under nighttime conditions. Results show that free-space QKD can provide secure real-time key distribution between parties who have a need to communicate secretly. Finally, they examine the feasibility of surface to satellite QKD.

  8. Experimental multiplexing of quantum key distribution with classical optical communication

    SciTech Connect

    Wang, Liu-Jun; Chen, Luo-Kan; Ju, Lei; Xu, Mu-Lan; Zhao, Yong; Chen, Kai; Chen, Zeng-Bing; Chen, Teng-Yun Pan, Jian-Wei

    2015-02-23

    We demonstrate the realization of quantum key distribution (QKD) when combined with classical optical communication, and synchronous signals within a single optical fiber. In the experiment, the classical communication sources use Fabry-Pérot (FP) lasers, which are implemented extensively in optical access networks. To perform QKD, multistage band-stop filtering techniques are developed, and a wavelength-division multiplexing scheme is designed for the multi-longitudinal-mode FP lasers. We have managed to maintain sufficient isolation among the quantum channel, the synchronous channel and the classical channels to guarantee good QKD performance. Finally, the quantum bit error rate remains below a level of 2% across the entire practical application range. The proposed multiplexing scheme can ensure low classical light loss, and enables QKD over fiber lengths of up to 45 km simultaneously when the fibers are populated with bidirectional FP laser communications. Our demonstration paves the way for application of QKD to current optical access networks, where FP lasers are widely used by the end users.

  9. Experimental multiplexing of quantum key distribution with classical optical communication

    NASA Astrophysics Data System (ADS)

    Wang, Liu-Jun; Chen, Luo-Kan; Ju, Lei; Xu, Mu-Lan; Zhao, Yong; Chen, Kai; Chen, Zeng-Bing; Chen, Teng-Yun; Pan, Jian-Wei

    2015-02-01

    We demonstrate the realization of quantum key distribution (QKD) when combined with classical optical communication, and synchronous signals within a single optical fiber. In the experiment, the classical communication sources use Fabry-Pérot (FP) lasers, which are implemented extensively in optical access networks. To perform QKD, multistage band-stop filtering techniques are developed, and a wavelength-division multiplexing scheme is designed for the multi-longitudinal-mode FP lasers. We have managed to maintain sufficient isolation among the quantum channel, the synchronous channel and the classical channels to guarantee good QKD performance. Finally, the quantum bit error rate remains below a level of 2% across the entire practical application range. The proposed multiplexing scheme can ensure low classical light loss, and enables QKD over fiber lengths of up to 45 km simultaneously when the fibers are populated with bidirectional FP laser communications. Our demonstration paves the way for application of QKD to current optical access networks, where FP lasers are widely used by the end users.

  10. FAST TRACK COMMUNICATION: Reversible arithmetic logic unit for quantum arithmetic

    NASA Astrophysics Data System (ADS)

    Kirkedal Thomsen, Michael; Glück, Robert; Axelsen, Holger Bock

    2010-09-01

    This communication presents the complete design of a reversible arithmetic logic unit (ALU) that can be part of a programmable reversible computing device such as a quantum computer. The presented ALU is garbage free and uses reversible updates to combine the standard reversible arithmetic and logical operations in one unit. Combined with a suitable control unit, the ALU permits the construction of an r-Turing complete computing device. The garbage-free ALU developed in this communication requires only 6n elementary reversible gates for five basic arithmetic-logical operations on two n-bit operands and does not use ancillae. This remarkable low resource consumption was achieved by generalizing the V-shape design first introduced for quantum ripple-carry adders and nesting multiple V-shapes in a novel integrated design. This communication shows that the realization of an efficient reversible ALU for a programmable computing device is possible and that the V-shape design is a very versatile approach to the design of quantum networks.

  11. Plan of advanced satellite communications experiment using ETS-VI

    NASA Technical Reports Server (NTRS)

    Shiomi, Tadashi

    1988-01-01

    Communications Research Laboratory (CRL, Ministry of Posts and Telecommunications, Japan) has been engaged in development of three advanced satellite communication payloads aiming at experiments by Japan's 2-ton class Engineering Test Satellite VI (ETS-VI) which is to be launched in H-II rocket by NASDA in August 1992. CRL's three experimental systems are: (1) S-band inter-satellite communications; (2) millimeter-wave inter-satellite and personal-satellite communications; and (3) optical inter-satellite communications. CRL develops experimental optical communication system with telescope of 75 mm diameter which has gimbal mirror beam pointing/tracking mechanism. The onboard system has fundamental optical communication functions with laser diode transmitter of wavelength 0.83 micron, laser beam point-ahead mechanism, receiver of wavelength 0.51 micron, modulation/demodulation subsystem, and so on.

  12. Mathematical foundations of quantum mechanics: An advanced short course

    NASA Astrophysics Data System (ADS)

    Moretti, Valter

    2016-08-01

    This paper collects and extends the lectures I gave at the “XXIV International Fall Workshop on Geometry and Physics” held in Zaragoza (Spain) during September 2015. Within these lectures I review the formulation of Quantum Mechanics, and quantum theories in general, from a mathematically advanced viewpoint, essentially based on the orthomodular lattice of elementary propositions, discussing some fundamental ideas, mathematical tools and theorems also related to the representation of physical symmetries. The final step consists of an elementary introduction the so-called (C∗-) algebraic formulation of quantum theories.

  13. Advanced Communication Technology Satellite (ACTS) multibeam antenna technology verification experiments

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.; Larko, Jeffrey M.; Lagin, Alan R.

    1992-01-01

    The Advanced Communication Technology Satellite (ACTS) is a key to reaching NASA's goal of developing high-risk, advanced communications technology using multiple frequency bands to support the nation's future communication needs. Using the multiple, dynamic hopping spot beams, and advanced on board switching and processing systems, ACTS will open a new era in communications satellite technology. One of the key technologies to be validated as part of the ACTS program is the multibeam antenna with rapidly reconfigurable hopping and fixed spot beam to serve users equipped with small-aperature terminals within the coverage areas. The proposed antenna technology experiments are designed to evaluate in-orbit ACTS multibeam antenna performance (radiation pattern, gain, cross pol levels, etc.).

  14. MMIC technology for advanced space communications systems

    NASA Technical Reports Server (NTRS)

    Downey, A. N.; Connolly, D. J.; Anzic, G.

    1984-01-01

    The current NASA program for 20 and 30 GHz monolithic microwave integrated circuit (MMIC) technology is reviewed. The advantages of MMIC are discussed. Millimeter wavelength MMIC applications and technology for communications systems are discussed. Passive and active MMIC compatible components for millimeter wavelength applications are investigated. The cost of a millimeter wavelength MMIC's is projected.

  15. Advances and prospects in visible light communications

    NASA Astrophysics Data System (ADS)

    Hongda, Chen; Chunhui, Wu; Honglei, Li; Xiongbin, Chen; Zongyu, Gao; Shigang, Cui; Qin, Wang

    2016-01-01

    Visible light communication (VLC) is an emerging technology in optical wireless communication (OWC) that has attracted worldwide research in recent years. VLC can combine communication and illumination together, which could be applied in many application scenarios such as visible light communication local area networks (VLANs), indoor localization, and intelligent lighting. In recent years, pioneering and significant work have been made in the field of VLC. In this paper, an overview of the recent progress in VLC is presented. We also demonstrate our recent experiment results including bidirectional 100 Mbit/s VLAN or Li-Fi system based on OOK modulation without blue filter. The VLC systems that we proposed are good solutions for high-speed VLC application systems with low-cost and low-complexity. VLC technology shows a bright future due to its inherent advantages, shortage of RF spectra and ever increasing popularity of white LEDs. Project supported by the National High Technology Research and Development Program of China (Nos. 2015AA033303, 2013AA013602, 2013AA013603, 2013AA03A104), the National Natural Science Foundation of China (Nos. 61178051, 61321063, 61335010, 61178048, 61275169), and the National Basic Research Program of China (Nos. 2013CB329205, 2011CBA00608).

  16. The Advanced Communications Technology Satellite (ACTS) capabilities for serving science

    NASA Technical Reports Server (NTRS)

    Meyer, Thomas R.

    1990-01-01

    Results of research on potential science applications of the NASA Advanced Communications Technology Satellite (ACTS) are presented. Discussed here are: (1) general research on communications related issues; (2) a survey of science-related activities and programs in the local area; (3) interviews of selected scientists and associated telecommunications support personnel whose projects have communications requirements; (4) analysis of linkages between ACTS functionality and science user communications activities and modes of operation; and (5) an analysis of survey results and the projection of conclusions to a national scale.

  17. Design and analysis of communication protocols for quantum repeater networks

    NASA Astrophysics Data System (ADS)

    Jones, Cody; Kim, Danny; Rakher, Matthew T.; Kwiat, Paul G.; Ladd, Thaddeus D.

    2016-08-01

    We analyze how the performance of a quantum-repeater network depends on the protocol employed to distribute entanglement, and we find that the choice of repeater-to-repeater link protocol has a profound impact on entanglement-distribution rate as a function of hardware parameters. We develop numerical simulations of quantum networks using different protocols, where the repeater hardware is modeled in terms of key performance parameters, such as photon generation rate and collection efficiency. These parameters are motivated by recent experimental demonstrations in quantum dots, trapped ions, and nitrogen-vacancy centers in diamond. We find that a quantum-dot repeater with the newest protocol (‘MidpointSource’) delivers the highest entanglement-distribution rate for typical cases where there is low probability of establishing entanglement per transmission, and in some cases the rate is orders of magnitude higher than other schemes. Our simulation tools can be used to evaluate communication protocols as part of designing a large-scale quantum network.

  18. Advances in Quantum Trajectory Approaches to Dynamics

    NASA Astrophysics Data System (ADS)

    Askar, Attila

    2001-03-01

    The quantum fluid dynamics (QFD) formulation is based on the separation of the amplitude and phase of the complex wave function in Schrodinger's equation. The approach leads to conservation laws for an equivalent "gas continuum". The Lagrangian [1] representation corresponds to following the particles of the fluid continuum, i. e. calculating "quantum trajectories". The Eulerian [2] representation on the other hand, amounts to observing the dynamics of the gas continuum at the points of a fixed coordinate frame. The combination of several factors leads to a most encouraging computational efficiency. QFD enables the numerical analysis to deal with near monotonic amplitude and phase functions. The Lagrangian description concentrates the computation effort to regions of highest probability as an optimal adaptive grid. The Eulerian representation allows the study of multi-coordinate problems as a set of one-dimensional problems within an alternating direction methodology. An explicit time integrator limits the increase in computational effort with the number of discrete points to linear. Discretization of the space via local finite elements [1,2] and global radial functions [3] will be discussed. Applications include wave packets in four-dimensional quadratic potentials and two coordinate photo-dissociation problems for NOCl and NO2. [1] "Quantum fluid dynamics (QFD) in the Lagrangian representation with applications to photo-dissociation problems", F. Sales, A. Askar and H. A. Rabitz, J. Chem. Phys. 11, 2423 (1999) [2] "Multidimensional wave-packet dynamics within the fluid dynamical formulation of the Schrodinger equation", B. Dey, A. Askar and H. A. Rabitz, J. Chem. Phys. 109, 8770 (1998) [3] "Solution of the quantum fluid dynamics equations with radial basis function interpolation", Xu-Guang Hu, Tak-San Ho, H. A. Rabitz and A. Askar, Phys. Rev. E. 61, 5967 (2000)

  19. Underground communications and tracking technology advances

    SciTech Connect

    Fiscor, S.

    2007-03-15

    As the June 2009 deadline set by the MINER Act grows near, several technologies have emerged as possible options for communicating and tracking underground coal miners in the event of an emergency or disaster. NIOSH is currently deciding how best to invest $10 million assigned by Congress under an Emergency Supplementary Appropriations Act (ESA) to research and develop mine safety technology. Medium and ultra high frequency (UHF) systems seem to be leading the pack with radio frequency identification (RFID) tags serving as the tracking system. Wireless mesh systems can serve as a communications infrastructure and they can do much more. Even more technologies continue to emerge, such as inertial navigation tracking systems. Mines are discovering the wonders of modern voice and data communications underground. Still no one know if it is economically practical to design a system that will function after a coal mine explosion. From the nineteen systems submitted to MSHA's request for information (RFI), six systems were selected that represented most of the technologies that had been proposed: the Rajant Breadcrumb, Innovative Wireless, Concurrent Technologies/Time Domain, Transtek, Gamma Services, and the Kutta Consulting systems. They were tested at CONSOL Energy's McElroy mine in April 2006. MSHA felt that all of those systems needed a significant amount of work before they were ready for use in a underground coal mining environment. The agency continues to work with these, and other manufacturers, to assist in arranging for field demonstration and then to gain MSHA approval.

  20. Advanced nurse-patient communication system.

    PubMed

    Unluturk, Mehmet S

    2012-08-01

    Effective communication is the most important part of any healthcare organization. For many years, hospital nurse call solutions had been stand-alone systems with occasional integration to pocket paging for outputting patient call alerts to mobile staff. In the late 1990's, technology enabled in-building wireless phones to supplement or replace paging systems as a means of not only sending alerts, but also enabling voice communication between mobile staff and patients. Today's nurse call market requires integration of additional information from location and ADT (admit, discharge, transfer) systems into what have traditionally been nurse call applications. This system information is required not only at the nursing station, pagers, and phones, but also at PC's placed on each patient care floor in hallways, nurse stations, and offices, and at areas away from the patients, including administrator and clinical engineering offices. It is crucial that nurses have the latest patient information in their hand wherever they go in the hospital. In this paper, MatchMaker.NET has been developed to integrate all these technologies into the hospital's LAN to improve nurse-patient communication. PMID:21541690

  1. An Immune Quantum Communication Model for Dephasing Noise Using Four-Qubit Cluster State

    NASA Astrophysics Data System (ADS)

    Wang, Rui-jin; Li, Dong-fen; Qin, Zhi-guang

    2016-01-01

    Quantum secure communication of dephasing in the presence of noise is a hot spot in research in the field of quantum secure communication. Quantum steganography aims is to transfer secret information in public quantum channel. But because effect of annealing phase noise, quantum states which is need to transfer easily delayed or changed. So, quantum steganography is very meaning apply to transmit secret information covertly in quantum noisy channels. The article introduced dephasing noise impact on the physics of quantum state, through the theoretical research, construct the logic of quantum states to back the phase noise immunity, and construct the decoherence free subspace, It can guarantees fidelity secret information exchange through quantum communication model in a noisy environment.

  2. The Army's Use of the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Ilse, Kenneth

    1996-01-01

    Tactical operations require military commanders to be mobile and have a high level of independence in their actions. Communications capabilities providing intelligence and command orders in these tactical situations have been limited to simple voice communications or low-rate narrow bandwidth communications because of the need for immediate reliable connectivity. The Advanced Communications Technology Satellite (ACTS) has brought an improved communications tool to the tactical commander giving the ability to gain access to a global communications system using high data rates and wide bandwidths. The Army has successfully tested this new capability of bandwidth-on-demand and high data rates for commanders in real-world conditions during Operation UPHOLD DEMOCRACY in Haiti during the fall and winter of 1994. This paper examines ACTS use by field commanders and details the success of the ACTS system in support of a wide variety of field condition command functions.

  3. Advanced Sensors Boost Optical Communication, Imaging

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Brooklyn, New York-based Amplification Technologies Inc. (ATI), employed Phase I and II SBIR funding from NASA s Jet Propulsion Laboratory to forward the company's solid-state photomultiplier technology. Under the SBIR, ATI developed a small, energy-efficient, extremely high-gain sensor capable of detecting light down to single photons in the near infrared wavelength range. The company has commercialized this technology in the form of its NIRDAPD photomultiplier, ideal for use in free space optical communications, lidar and ladar, night vision goggles, and other light sensing applications.

  4. Long-distance quantum communication with neutral atoms

    SciTech Connect

    Razavi, Mohsen; Shapiro, Jeffrey H.

    2006-04-15

    The architecture proposed by Duan, Lukin, Cirac, and Zoller (DLCZ) for long-distance quantum communication with atomic ensembles is analyzed. Its fidelity and throughput in entanglement distribution, entanglement swapping, and quantum teleportation is derived within a framework that accounts for multiple excitations in the ensembles as well as loss and asymmetries in the channel. The DLCZ performance metrics that are obtained are compared to the corresponding results for the trapped-atom quantum communication architecture that has been proposed by a team from the Massachusetts Institute of Technology and Northwestern University (MIT and NU). Both systems are found to be capable of high-fidelity entanglement distribution. However, the DLCZ scheme only provides conditional teleportation and repeater operation, whereas the MIT-NU architecture affords full Bell-state measurements on its trapped atoms. Moreover, it is shown that achieving unity conditional fidelity in DLCZ teleportation and repeater operation requires ideal photon-number resolving detectors. The maximum conditional fidelities for DLCZ teleportation and repeater operation that can be realized with nonresolving detectors are 1/2 and 2/3, respectively.

  5. Advances in superconducting quantum electronic microcircuit fabrication

    NASA Technical Reports Server (NTRS)

    Kirschman, R. K.; Notarys, H. A.; Mercereau, J. E.

    1975-01-01

    Standard microelectronic fabrication techniques have been utilized to produce batch quantities of superconducting quantum electronic devices and circuits. The overall goal is a fabrication technology yielding circuits that are rugged and stable and capable of being fabricated controllably and reproducibly in sizeable quantities. Our progress toward this goal is presented, with primary emphasis on the most recent work, which includes the use of electron-beam lithography and techniques of hybrid microelectronics. Several prototype microcircuits have been successfully fabricated. These microcircuits are formed in a thin-film parent material consisting of layers of superconducting and normal metals, and use proximity-effect structures as the active circuit elements.

  6. Potential markets for advanced satellite communications

    NASA Technical Reports Server (NTRS)

    Adamson, Steven; Roberts, David; Schubert, Leroy; Smith, Brian; Sogegian, Robert; Walters, Daniel

    1993-01-01

    This report identifies trends in the volume and type of traffic offered to the U.S. domestic communications infrastructure and extrapolates these trends through the year 2011. To describe how telecommunications service providers are adapting to the identified trends, this report assesses the status, plans, and capacity of the domestic communications infrastructure. Cable, satellite, and radio components of the infrastructure are examined separately. The report also assesses the following major applications making use of the infrastructure: (1) Broadband services, including Broadband Integrated Services Digital Network (BISDN), Switched Multimegabit Data Service (SMDS), and frame relay; (2) mobile services, including voice, location, and paging; (3) Very Small Aperture Terminals (VSAT), including mesh VSAT; and (4) Direct Broadcast Satellite (DBS) for audio and video. The report associates satellite implementation of specific applications with market segments appropriate to their features and capabilities. The volume and dollar value of these market segments are estimated. For the satellite applications able to address the needs of significant market segments, the report also examines the potential of each satellite-based application to capture business from alternative technologies.

  7. Potential markets for advanced satellite communications

    NASA Astrophysics Data System (ADS)

    Adamson, Steven; Roberts, David; Schubert, Leroy; Smith, Brian; Sogegian, Robert; Walters, Daniel

    1993-09-01

    This report identifies trends in the volume and type of traffic offered to the U.S. domestic communications infrastructure and extrapolates these trends through the year 2011. To describe how telecommunications service providers are adapting to the identified trends, this report assesses the status, plans, and capacity of the domestic communications infrastructure. Cable, satellite, and radio components of the infrastructure are examined separately. The report also assesses the following major applications making use of the infrastructure: (1) Broadband services, including Broadband Integrated Services Digital Network (BISDN), Switched Multimegabit Data Service (SMDS), and frame relay; (2) mobile services, including voice, location, and paging; (3) Very Small Aperture Terminals (VSAT), including mesh VSAT; and (4) Direct Broadcast Satellite (DBS) for audio and video. The report associates satellite implementation of specific applications with market segments appropriate to their features and capabilities. The volume and dollar value of these market segments are estimated. For the satellite applications able to address the needs of significant market segments, the report also examines the potential of each satellite-based application to capture business from alternative technologies.

  8. 76 FR 56244 - Dialpoint Communications Corp., Pacel Corp., Quantum Group, Inc. (The), and Tradequest...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-12

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Dialpoint Communications Corp., Pacel Corp., Quantum Group, Inc. (The), and Tradequest... accurate information concerning the securities of Quantum Group, Inc. (The) because it has not filed...

  9. A Communication Architecture for an Advanced Extravehicular Mobile Unit

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Sands, Obed S.; Bakula, Casey J.; Oldham, Daniel R.; Wright, Ted; Bradish, Martin A.; Klebau, Joseph M.

    2014-01-01

    This document describes the communication architecture for the Power, Avionics and Software (PAS) 1.0 subsystem for the Advanced Extravehicular Mobility Unit (AEMU). The following systems are described in detail: Caution Warning and Control System, Informatics, Storage, Video, Audio, Communication, and Monitoring Test and Validation. This document also provides some background as well as the purpose and goals of the PAS subsystem being developed at Glenn Research Center (GRC).

  10. Quantum memory receiver for superadditive communication using binary coherent states

    NASA Astrophysics Data System (ADS)

    Klimek, Aleksandra; Jachura, Michał; Wasilewski, Wojciech; Banaszek, Konrad

    2016-11-01

    We propose a simple architecture based on multimode quantum memories for collective readout of classical information keyed using a pair coherent states, exemplified by the well-known binary phase shift keying format. Such a configuration enables demonstration of the superadditivity effect in classical communication over quantum channels, where the transmission rate becomes enhanced through joint detection applied to multiple channel uses. The proposed scheme relies on the recently introduced idea to prepare Hadamard sequences of input symbols that are mapped by a linear optical transformation onto the pulse position modulation format [Guha, S. Phys. Rev. Lett. 2011, 106, 240502]. We analyze two versions of readout based on direct detection and an optional Dolinar receiver which implements the minimum-error measurement for individual detection of a binary coherent state alphabet.

  11. Quantum memory receiver for superadditive communication using binary coherent states

    PubMed Central

    Klimek, Aleksandra; Jachura, Michał; Wasilewski, Wojciech; Banaszek, Konrad

    2016-01-01

    We propose a simple architecture based on multimode quantum memories for collective readout of classical information keyed using a pair coherent states, exemplified by the well-known binary phase shift keying format. Such a configuration enables demonstration of the superadditivity effect in classical communication over quantum channels, where the transmission rate becomes enhanced through joint detection applied to multiple channel uses. The proposed scheme relies on the recently introduced idea to prepare Hadamard sequences of input symbols that are mapped by a linear optical transformation onto the pulse position modulation format [Guha, S. Phys. Rev. Lett. 2011, 106, 240502]. We analyze two versions of readout based on direct detection and an optional Dolinar receiver which implements the minimum-error measurement for individual detection of a binary coherent state alphabet.

  12. Complete hyperentangled-Bell-state analysis for quantum communication

    SciTech Connect

    Sheng Yubo; Deng Fuguo; Long Guilu

    2010-09-15

    It is impossible to unambiguously distinguish the four Bell states in polarization, resorting to linear optical elements only. Recently, the hyperentangled Bell state, the simultaneous entanglement in more than one degree of freedom, has been used to assist in the complete Bell-state analysis of the four Bell states. However, if the additional degree of freedom is qubitlike, one can only distinguish 7 from the group of 16 states. Here we present a way to distinguish the hyperentangled Bell states completely with the help of cross-Kerr nonlinearity. Also, we discuss its application in the quantum teleportation of a particle in an unknown state in two different degrees of freedom and in the entanglement swapping of hyperentangled states. These applications will increase the channel capacity of long-distance quantum communication.

  13. Advanced integrated WDM system for POF communication

    NASA Astrophysics Data System (ADS)

    Haupt, M.; Fischer, U. H. P.

    2009-01-01

    Polymer Optical Fibres (POFs) show clear advantages compared to copper and glass fibres. In essence, POFs are inexpensive, space-saving and not susceptible to electromagnetic interference. Thus, the usage of POFs have become a reasonable alternative in short distance data communication. Today, POFs are applied in a wide number of applications due to these specific advantages. These applications include automotive communication systems and in-house-networks. State-of-the-art is to transmit data with only one channel over POF, this limits the bandwidth. To solve this problem, an integrated MUX/DEMUX-element for WDM over POF is designed and developed to use multiple channels. This integration leads to low costs, therefore this component is suitable for mass market applications. The fundamental idea is to separate the chromatic parts of the light in its monochromatic components by means of a grating based on an aspheric mirror. Due to the high NA of the POF the setup has to be designed in a 3D-approach. Therefore this setup cannot be compared with the planar solutions available on market, they would result high losses in the 3rd dimension. To achieve a fast and optimized design an optical simulation program is used. Particular attention has to be paid to the design of the POF as a light source in the simulation program and the optimisation of the grating. The following realization of the demultiplexer is planed to be done with injection molding. This technology offers easy and very economical processing. These advantages make this technology first choice for optical components in the low-cost array.

  14. Advanced Topic: Quasi-Hermitian Quantum Systems

    NASA Astrophysics Data System (ADS)

    Curtright, Thomas L.; Fairlie, David B.; Zachos, Cosmas K.

    2014-11-01

    So far, the discussion has limited itself to hermitian operators and systems. However, superficially non-hermitian Hamiltonian quantum systems are also of considerable current interest, especially in the context of PT symmetric models [Ben07, Mos05], although many of the main ideas appeared earlier [SGH92, XA96]. For such systems, the Hilbert space structure is at first sight very different from that for hermitian Hamiltonian systems, inasmuch as the dual wavefunctions are not just the complex conjugates of the wavefunctions, or, equivalently, the Hilbert space metric is not the usual one. While it is possible to keep most of the compact Dirac notation in analyzing such systems, here we work with explicit functions and avoid abstract notation, in the hope to fully expose all the structure, rather than to hide it...

  15. Quantum secret sharing via local operations and classical communication

    PubMed Central

    Yang, Ying-Hui; Gao, Fei; Wu, Xia; Qin, Su-Juan; Zuo, Hui-Juan; Wen, Qiao-Yan

    2015-01-01

    We investigate the distinguishability of orthogonal multipartite entangled states in d-qudit system by restricted local operations and classical communication. According to these properties, we propose a standard (2, n)-threshold quantum secret sharing scheme (called LOCC-QSS scheme), which solves the open question in [Rahaman et al., Phys. Rev. A, 91, 022330 (2015)]. On the other hand, we find that all the existing (k, n)-threshold LOCC-QSS schemes are imperfect (or “ramp”), i.e., unauthorized groups can obtain some information about the shared secret. Furthermore, we present a (3, 4)-threshold LOCC-QSS scheme which is close to perfect. PMID:26586412

  16. Quantum secret sharing via local operations and classical communication.

    PubMed

    Yang, Ying-Hui; Gao, Fei; Wu, Xia; Qin, Su-Juan; Zuo, Hui-Juan; Wen, Qiao-Yan

    2015-01-01

    We investigate the distinguishability of orthogonal multipartite entangled states in d-qudit system by restricted local operations and classical communication. According to these properties, we propose a standard (2, n)-threshold quantum secret sharing scheme (called LOCC-QSS scheme), which solves the open question in [Rahaman et al., Phys. Rev. A, 91, 022330 (2015)]. On the other hand, we find that all the existing (k, n)-threshold LOCC-QSS schemes are imperfect (or "ramp"), i.e., unauthorized groups can obtain some information about the shared secret. Furthermore, we present a (3, 4)-threshold LOCC-QSS scheme which is close to perfect.

  17. Quantum Secure Direct Communication Based on Chaos with Authentication

    NASA Astrophysics Data System (ADS)

    Huang, Dazu; Chen, Zhigang; Guo, Ying; Lee, Moon Ho

    2007-12-01

    A quantum secure direct communication protocol based on chaos is proposed with authentication. It has an advantage over distributing the secret message directly and verifying the communicators’ identities with the assistance of a trusted center. To ensure the security of the secret message and the process of verification, the initial order of the travel particles is disturbed according to a chaotic sequence generated secretly via the general Arnold map. Security analysis demonstrates that the present scheme is secure against several attack strategies, such as the man-in-the-middle attack and Trojan horse attack.

  18. Advanced high capacity domestic satellite communications system

    NASA Astrophysics Data System (ADS)

    Iso, A.; Kohiyama, K.; Odate, H.; Ishida, N.

    1981-09-01

    The high capacity transmission of a 30/20 GHz and 50/40 GHz domestic satellite communication system is presented with an investigation of the relationship between satellite antenna pointing accuracy, multibeam antenna interference, and multisatellite interference. Antenna pointing is found to affect an antenna's gain and pattern and multibeam interference; thus the antenna beam width is defined to include antenna pointing accuracy. Results include a 6 m antenna gain of 69.5 dB at 20 GHz for 114 beams with a pointing accuracy of 0.05 deg, and a 17.6 m gain of 69.0 dB at 20 GHz for 630 beams with an accuracy of 0.01 deg. The frequency reuse number is given as a function of total beam number and pointing accuracy, and a bandwidth of 7 GHz allocated at 30/20 and 50/40 GHz is made possible by multispot beam antennas and linearly polarized waves.

  19. Communication: Test of quantum chemistry in vibrationally hot hydrogen molecules

    NASA Astrophysics Data System (ADS)

    Niu, M. L.; Salumbides, E. J.; Ubachs, W.

    2015-08-01

    Precision measurements are performed on highly excited vibrational quantum states of molecular hydrogen. The v = 12, J = 0 - 3 rovibrational levels of H2 ( X 1 Σg + ), lying only 2000 cm-1 below the first dissociation limit, were populated by photodissociation of H2S and their level energies were accurately determined by two-photon Doppler-free spectroscopy. A comparison between the experimental results on v = 12 level energies with the best ab initio calculations shows a good agreement, where the present experimental accuracy of 3.5 × 10-3 cm-1 is more precise than theory, hence providing a gateway to further test theoretical advances in this benchmark quantum system.

  20. Communication: Test of quantum chemistry in vibrationally hot hydrogen molecules.

    PubMed

    Niu, M L; Salumbides, E J; Ubachs, W

    2015-08-28

    Precision measurements are performed on highly excited vibrational quantum states of molecular hydrogen. The v = 12, J = 0 - 3 rovibrational levels of H2 (X(1)Σg (+)), lying only 2000 cm(-1) below the first dissociation limit, were populated by photodissociation of H2S and their level energies were accurately determined by two-photon Doppler-free spectroscopy. A comparison between the experimental results on v = 12 level energies with the best ab initio calculations shows a good agreement, where the present experimental accuracy of 3.5 × 10(-3) cm(-1) is more precise than theory, hence providing a gateway to further test theoretical advances in this benchmark quantum system.

  1. Glenn Research Center quantum communicator receiver design and development

    NASA Astrophysics Data System (ADS)

    Hizlan, Murad; Lekki, John D.; Nguyen, Binh V.

    2009-10-01

    We investigate, design, and develop a prototype real-time synchronous receiver for the second-generation quantum communicator recently developed at the National Aeronautics and Space Administration (NASA) Glenn Research Center. This communication system exploits the temporal coincidences between simultaneously fired low-power laser sources to communicate at power levels several orders of magnitude less than what is currently achievable through classical means, with the ultimate goal of creating ultra-low-power microsize optical communications and sensing devices. The proposed receiver uses a unique adaptation of the early-late gate method for symbol synchronization and a newly identified 31-bit synchronization word for frame synchronization. This receiver, implemented in a field-programmable gate array (FPGA), also provides a number of significant additional features over the existing non-real-time experimental receiver, such as real-time bit error rate (BER) statistics collection and display, and recovery and display of embedded textual information. It also exhibits an indefinite run time and statistics collection.

  2. Practical Quantum Communication and Cryptography for WDM Optical Networks

    NASA Astrophysics Data System (ADS)

    Kumar, Prem

    2004-11-01

    Keeping in mind the ubiquitous standard optical fiber for long-distance transmission and the widespread availability of efficient active and passive fiber devices, we have been developing telecom-band resources for practical quantum communication and cryptography in wave-division-multiplexed (WDM) optical networks. In this talk I present our recent results on two fronts: i) telecom-band in-fiber entanglement generation, storage, and long-distance distribution and ii) quantum-noise protected high-speed data encryption through an optically-amplified WDM line. Along the first front, with our in-fiber entanglement source all four Bell states can be readily produced and we have demonstrated violation of Bell's inequalities by up to 10 standard deviations of measurement uncertainty. With such a source we have demonstrated storage of entanglement for up to 1/8 of a millisecond. Furthermore, when each photon of the entangled pair is propagated in separate 25km-long standard fibers, high visibility quantum interference is still observed, demonstrating that this system is capable of long-distance (> 50 km) entanglement distribution. Along the second front, we have implemented a new quantum cryptographic scheme, based on Yuen's KCQ protocol, in which the inherent quantum noise of coherent states of light is used to perform the cryptographic service of data encryption. In this scheme a legitimate receiver, with use of a short, shared, secret-key, executes a simple binary decision rule on every transmitted bit. An eavesdropper, on the other hand, who does not possess the secret-key, is subjected to an irreducible quantum uncertainty in each measurement, even with the use of ideal detectors. We have implemented this scheme to demonstrate quantum-noise-protected data encryption at 650 Mbps through a 200 km, in-line amplified, WDM line. The line simultaneously carried two 10 Gbps standard data channels, 100 GHz on either side of the encrypted channel, which shows that this scheme

  3. Epidermal electronics with advanced capabilities in near-field communication.

    PubMed

    Kim, Jeonghyun; Banks, Anthony; Cheng, Huanyu; Xie, Zhaoqian; Xu, Sheng; Jang, Kyung-In; Lee, Jung Woo; Liu, Zhuangjian; Gutruf, Philipp; Huang, Xian; Wei, Pinghung; Liu, Fei; Li, Kan; Dalal, Mitul; Ghaffari, Roozbeh; Feng, Xue; Huang, Yonggang; Gupta, Sanjay; Paik, Ungyu; Rogers, John A

    2015-02-25

    Epidermal electronics with advanced capabilities in near field communications (NFC) are presented. The systems include stretchable coils and thinned NFC chips on thin, low modulus stretchable adhesives, to allow seamless, conformal contact with the skin and simultaneous capabilities for wireless interfaces to any standard, NFC-enabled smartphone, even under extreme deformation and after/during normal daily activities.

  4. New Opportunities with the Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Bauer, Robert

    1998-01-01

    Various issues associated with the Advanced Communications Technology Satellite (ACTS) are presented in viewgraph form. Specific topics include: 1) ACTS program review; 2) Spot beam locations; 3) Key ACTS technologies; 4) ACTS accomplishments; 5) Experiments operations; 6) Inclined orbit opportunity, mission and impact; 7) Modifications summary; 8) Experiment opportunity, categories, processes; and 9) Recent and ongoing activity.

  5. Quantum Secure Direct Communication in a noisy environment: Theory and Experiment

    NASA Astrophysics Data System (ADS)

    Long, Gui Lu

    Quantum communication holds promise for absolutely security in secret message transmission. Quantum secure direct communication (QSDC) is an important branch of the quantum communication in which secret messages are sent directly over a quantum channel with security[Phys. Rev. A 65 , 032302 (2002)]. QSDC offers higher security and is instantaneous in communication, and is a great improvement to the classical communication mode. It is also a powerful basic quantum communication primitive for constructing many other quantum communication tasks such as quantum bidding, quantum signature and quantum dialogue and so on. Since the first QSDC protocol proposed in 2000, it has become one of the extensive research focuses. In this talk, the basic ideas of QSDC will be reviewed, and major QSDC protocols will be described, such as the efficient-QSDC protocol, the two-step QSDC protocol, the one-time-pad QSDC protocol, the high-dimensional QSDC protocol and so on. Experimental progress is also developing steadily, and will also be reviewed. In particular, the quantum one-time-pad QSDC protocol has recently been successfully demonstrated experimentally[arXiv:1503.00451]. Work supported by China National Natural Science Foundation, the Ministry of Science and Technology of China.

  6. Quantum communication for satellite-to-ground networks with partially entangled states

    NASA Astrophysics Data System (ADS)

    Chen, Na; Quan, Dong-Xiao; Pei, Chang-Xing; Yang-Hong

    2015-02-01

    To realize practical wide-area quantum communication, a satellite-to-ground network with partially entangled states is developed in this paper. For efficiency and security reasons, the existing method of quantum communication in distributed wireless quantum networks with partially entangled states cannot be applied directly to the proposed quantum network. Based on this point, an efficient and secure quantum communication scheme with partially entangled states is presented. In our scheme, the source node performs teleportation only after an end-to-end entangled state has been established by entanglement swapping with partially entangled states. Thus, the security of quantum communication is guaranteed. The destination node recovers the transmitted quantum bit with the help of an auxiliary quantum bit and specially defined unitary matrices. Detailed calculations and simulation analyses show that the probability of successfully transferring a quantum bit in the presented scheme is high. In addition, the auxiliary quantum bit provides a heralded mechanism for successful communication. Based on the critical components that are presented in this article an efficient, secure, and practical wide-area quantum communication can be achieved. Project supported by the National Natural Science Foundation of China (Grant Nos. 61072067 and 61372076), the 111 Project (Grant No. B08038), the Fund from the State Key Laboratory of Integrated Services Networks (Grant No. ISN 1001004), and the Fundamental Research Funds for the Central Universities (Grant Nos. K5051301059 and K5051201021).

  7. Information Trade-Offs for Optical Quantum Communication

    NASA Astrophysics Data System (ADS)

    Wilde, Mark M.; Hayden, Patrick; Guha, Saikat

    2012-04-01

    Recent work has precisely characterized the achievable trade-offs between three key information processing tasks—classical communication (generation or consumption), quantum communication (generation or consumption), and shared entanglement (distribution or consumption), measured in bits, qubits, and ebits per channel use, respectively. Slices and corner points of this three-dimensional region reduce to well-known protocols for quantum channels. A trade-off coding technique can attain any point in the region and can outperform time sharing between the best-known protocols for accomplishing each information processing task by itself. Previously, the benefits of trade-off coding that had been found were too small to be of practical value (viz., for the dephasing and the universal cloning machine channels). In this Letter, we demonstrate that the associated performance gains are in fact remarkably high for several physically relevant bosonic channels that model free-space or fiber-optic links, thermal-noise channels, and amplifiers. We show that significant performance gains from trade-off coding also apply when trading photon-number resources between transmitting public and private classical information simultaneously over secret-key-assisted bosonic channels.

  8. Information trade-offs for optical quantum communication.

    PubMed

    Wilde, Mark M; Hayden, Patrick; Guha, Saikat

    2012-04-01

    Recent work has precisely characterized the achievable trade-offs between three key information processing tasks-classical communication (generation or consumption), quantum communication (generation or consumption), and shared entanglement (distribution or consumption), measured in bits, qubits, and ebits per channel use, respectively. Slices and corner points of this three-dimensional region reduce to well-known protocols for quantum channels. A trade-off coding technique can attain any point in the region and can outperform time sharing between the best-known protocols for accomplishing each information processing task by itself. Previously, the benefits of trade-off coding that had been found were too small to be of practical value (viz., for the dephasing and the universal cloning machine channels). In this Letter, we demonstrate that the associated performance gains are in fact remarkably high for several physically relevant bosonic channels that model free-space or fiber-optic links, thermal-noise channels, and amplifiers. We show that significant performance gains from trade-off coding also apply when trading photon-number resources between transmitting public and private classical information simultaneously over secret-key-assisted bosonic channels. PMID:22540777

  9. Characterization of measurements in quantum communication. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Chan, V. W. S.

    1975-01-01

    A characterization of quantum measurements by operator valued measures is presented. The generalized measurements include simultaneous approximate measurement of noncommuting observables. This characterization is suitable for solving problems in quantum communication. Two realizations of such measurements are discussed. The first is by adjoining an apparatus to the system under observation and performing a measurement corresponding to a self-adjoint operator in the tensor-product Hilbert space of the system and apparatus spaces. The second realization is by performing, on the system alone, sequential measurements that correspond to self-adjoint operators, basing the choice of each measurement on the outcomes of previous measurements. Simultaneous generalized measurements are found to be equivalent to a single finer grain generalized measurement, and hence it is sufficient to consider the set of single measurements. An alternative characterization of generalized measurement is proposed. It is shown to be equivalent to the characterization by operator-values measures, but it is potentially more suitable for the treatment of estimation problems. Finally, a study of the interaction between the information-carrying system and a measurement apparatus provides clues for the physical realizations of abstractly characterized quantum measurements.

  10. Advanced Communication and Networking Technologies for Mars Exploration

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul; Hayden, Jeff; Agre, Jonathan R.; Clare, Loren P.; Yan, Tsun-Yee

    2001-01-01

    Next-generation Mars communications networks will provide communications and navigation services to a wide variety of Mars science vehicles including: spacecraft that are arriving at Mars, spacecraft that are entering and descending in the Mars atmosphere, scientific orbiter spacecraft, spacecraft that return Mars samples to Earth, landers, rovers, aerobots, airplanes, and sensing pods. In the current architecture plans, the communication services will be provided using capabilities deployed on the science vehicles as well as dedicated communication satellites that will together make up the Mars network. This network will evolve as additional vehicles arrive, depart or end their useful missions. Cost savings and increased reliability will result from the ability to share communication services between missions. This paper discusses the basic architecture that is needed to support the Mars Communications Network part of NASA's Space Science Enterprise (SSE) communications architecture. The network may use various networking technologies such as those employed in the terrestrial Internet, as well as special purpose deep-space protocols to move data and commands autonomously between vehicles, at disparate Mars vicinity sites (on the surface or in near-Mars space) and between Mars vehicles and earthbound users. The architecture of the spacecraft on-board local communications is being reconsidered in light of these new networking requirements. The trend towards increasingly autonomous operation of the spacecraft is aimed at reducing the dependence on resource scheduling provided by Earth-based operators and increasing system fault tolerance. However, these benefits will result in increased communication and software development requirements. As a result, the envisioned Mars communications infrastructure requires both hardware and protocol technology advancements. This paper will describe a number of the critical technology needs and some of the ongoing research

  11. Commercialization of Advanced Communications Technology Satellite (ACTS) technology

    NASA Astrophysics Data System (ADS)

    Plecity, Mark S.; Strickler, Walter M.; Bauer, Robert A.

    1996-03-01

    In an on-going effort to maintain United States leadership in communication satellite technology, the National Aeronautics and Space Administration (NASA), led the development of the Advanced Communications Technology Satellite (ACTS). NASA's ACTS program provides industry, academia, and government agencies the opportunity to perform both technology and telecommunication service experiments with a leading-edge communication satellite system. Over 80 organizations are using ACTS as a multi server test bed to establish communication technologies and services of the future. ACTS was designed to provide demand assigned multiple access (DAMA) digital communications with a minimum switchable circuit bandwidth of 64 Kbps, and a maximum channel bandwidth of 900 MHZ. It can, therefore, provide service to thin routes as well as connect fiber backbones in supercomputer networks, across oceans, or restore full communications in the event of national or manmade disaster. Service can also be provided to terrestrial and airborne mobile users. Commercial applications of ACTS technologies include: telemedicine; distance education; Department of Defense operations; mobile communications, aeronautical applications, terrestrial applications, and disaster recovery. This paper briefly describes the ACTS system and the enabling technologies employed by ACTS including Ka-band hopping spot beams, on-board routing and switching, and rain fade compensation. When used in conjunction with a time division multiple access (TDMA) architecture, these technologies provide a higher capacity, lower cost satellite system. Furthermore, examples of completed user experiments, future experiments, and plans of organizations to commercialize ACTS technology in their own future offerings will be discussed.

  12. A general method for selecting quantum channel for bidirectional controlled state teleportation and other schemes of controlled quantum communication

    NASA Astrophysics Data System (ADS)

    Thapliyal, Kishore; Verma, Amit; Pathak, Anirban

    2015-12-01

    Recently, a large number of protocols for bidirectional controlled state teleportation (BCST) have been proposed using n-qubit entangled states (nin {5,6,7}) as quantum channel. Here, we propose a general method of selecting multiqubit (n>4) quantum channels suitable for BCST and show that all the channels used in the existing protocols of BCST can be obtained using the proposed method. Further, it is shown that the quantum channels used in the existing protocols of BCST form only a negligibly small subset of the set of all the quantum channels that can be constructed using the proposed method to implement BCST. It is also noted that all these quantum channels are also suitable for controlled bidirectional remote state preparation. Following the same logic, methods for selecting quantum channels for other controlled quantum communication tasks, such as controlled bidirectional joint remote state preparation and controlled quantum dialogue, are also provided.

  13. Optical communication with two-photon coherent stages. I - Quantum-state propagation and quantum-noise reduction

    NASA Technical Reports Server (NTRS)

    Yuen, H. P.; Shapiro, J. H.

    1978-01-01

    To determine the ultimate performance limitations imposed by quantum effects, it is also essential to consider optimum quantum-state generation. Certain 'generalized' coherent states of the radiation field possess novel quantum noise characteristics that offer the potential for greatly improved optical communications. These states have been called two-photon coherent states because they can be generated, in principle, by stimulated two-photon processes. The use of two-photon coherent state (TCS) radiation in free-space optical communications is considered. A simple theory of quantum state propagation is developed. The theory provides the basis for representing the free-space channel in a quantum-mechanical form convenient for communication analysis. The new theory is applied to TCS radiation.

  14. Efficient bounds on quantum-communication rates via their reduced variants

    SciTech Connect

    Nowakowski, Marcin L.; Horodecki, Pawel

    2010-10-15

    We investigate one-way communication scenarios where Bob operating on his component can transfer some subsystem to the environment. We define reduced versions of quantum-communication rates and, further, prove upper bounds on a one-way quantum secret key, distillable entanglement, and quantum-channel capacity by means of their reduced versions. It is shown that in some cases they drastically improve their estimation.

  15. Eavesdropping on quantum secure direct communication in quantum channels with arbitrarily low loss rate

    NASA Astrophysics Data System (ADS)

    Zawadzki, Piotr

    2016-04-01

    Quantum attacks that provide an undetectable eavesdropping of the ping-pong protocol operating over lossy quantum channels have already been demonstrated by Wójcik (Phys Rev Lett 90(15):157901, 2003) and Zhang et al. (Phys Lett A 333(12):46-50, 2004). These attacks provide a maximum information gain of 0.311 bits per protocol cycle as long as the induced loss rate remains acceptable. Otherwise, the skipping of some protocol cycles is advised to stay within an accepted loss limit. Such policy leads to a reduction in information gain proportional to the number of skipped cycles. The attack transformation parametrized by the induced loss ratio is proposed. It provides smaller reduction in information gain when the losses accepted by the communicating parties are too low to mount the most effective attack. Other properties of the attack remain the same.

  16. Study of optimum methods of optical communication. [accounting for the effects of the turbulent atmosphere and quantum mechanics

    NASA Technical Reports Server (NTRS)

    Harger, R. O.

    1974-01-01

    Abstracts are reported relating to the techniques used in the research concerning optical transmission of information. Communication through the turbulent atmosphere, quantum mechanics, and quantum communication theory are discussed along with the results.

  17. Display-based communications for advanced transport aircraft

    NASA Technical Reports Server (NTRS)

    Lee, Alfred T.

    1989-01-01

    The next generation of civil transport aircraft will depend increasingly upon ground-air-ground and satellite data link for information critical to safe and efficient air transportation. Previous studies which examined the concept of display-based communications in addition to, or in lieu of, conventional voice transmissions are reviewed. A full-mission flight simulation comparing voice and display-based communication modes in an advanced transport aircraft is also described. The results indicate that a display-based mode of information transfer does not result in significantly increased aircrew workload, but does result in substantially increased message acknowledgment times when compared to conventional voice transmissions. User acceptance of the display-based communication system was generally high, replicating the findings of previous studies. However, most pilots tested expressed concern over the potential loss of information available from frequency monitoring which might result from the introduction of discrete address communications. Concern was expressed by some pilots for the reduced time available to search for conflicting traffic when using the communications display system. The implications of the findings for the design of display-based communications are discussed.

  18. Performance evaluation of cognitive radio in advanced metering infrastructure communication

    NASA Astrophysics Data System (ADS)

    Hiew, Yik-Kuan; Mohd Aripin, Norazizah; Din, Norashidah Md

    2016-03-01

    Smart grid is an intelligent electricity grid system. A reliable two-way communication system is required to transmit both critical and non-critical smart grid data. However, it is difficult to locate a huge chunk of dedicated spectrum for smart grid communications. Hence, cognitive radio based communication is applied. Cognitive radio allows smart grid users to access licensed spectrums opportunistically with the constraint of not causing harmful interference to licensed users. In this paper, a cognitive radio based smart grid communication framework is proposed. Smart grid framework consists of Home Area Network (HAN) and Advanced Metering Infrastructure (AMI), while AMI is made up of Neighborhood Area Network (NAN) and Wide Area Network (WAN). In this paper, the authors only report the findings for AMI communication. AMI is smart grid domain that comprises smart meters, data aggregator unit, and billing center. Meter data are collected by smart meters and transmitted to data aggregator unit by using cognitive 802.11 technique; data aggregator unit then relays the data to billing center using cognitive WiMAX and TV white space. The performance of cognitive radio in AMI communication is investigated using Network Simulator 2. Simulation results show that cognitive radio improves the latency and throughput performances of AMI. Besides, cognitive radio also improves spectrum utilization efficiency of WiMAX band from 5.92% to 9.24% and duty cycle of TV band from 6.6% to 10.77%.

  19. Hard ACTS to follow. [NASA Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Moy, L.

    1986-01-01

    The Advanced Communications Technology Satellite (ACTS), the third phase of NASA's 30/20 GHz satellite communications program, is praised for its frugal usage of both the geosynchronous orbital arch and the frequency spectrum resources necessary for communications satellites. Its objective is to verify Ka-band satellite communications concepts and to develop a flight and ground system for validation of the multibeam communications proof-of-concept technologies. The ACTS ground segment (comprised of four types of terminals) is designed to compliment the spacecraft for the SS launch in 1989. Precise coordination between the ground and spacecraft segments is performed by the baseband processor (BBP), which is an in-orbit switchboard, and the tracking error word, which enables the ground terminals to remain synchronized with onboard timing. Fixed spot beams and scan beams, comprising the two types of spot beams used, both operate at the same frequency and hence, conserve frequency resources. In addition, the time division multiple access serves to enhance system efficiency. It is concluded that Ka-band satellites are a practical approach to the better usage of those resources potentially threatened by communications satellites. Comprehensive graphs and block diagrams of the system are included.

  20. Measurement-based noiseless linear amplification for quantum communication

    NASA Astrophysics Data System (ADS)

    Chrzanowski, H. M.; Walk, N.; Haw, J. Y.; Thearle, O.; Assad, S. M.; Janousek, J.; Hosseini, S.; Ralph, T. C.; Symul, T.; Lam, P. K.

    2014-11-01

    Entanglement distillation is an indispensable ingredient in extended quantum communication networks. Distillation protocols are necessarily non-deterministic and require non-trivial experimental techniques such as noiseless amplification. We show that noiseless amplification could be achieved by performing a post-selective filtering of measurement outcomes. We termed this protocol measurement-based noiseless linear amplification (MBNLA). We apply this protocol to entanglement that suffers transmission loss of up to the equivalent of 100km of optical fibre and show that it is capable of distilling entanglement to a level stronger than that achievable by transmitting a maximally entangled state through the same channel. We also provide a proof-of-principle demonstration of secret key extraction from an otherwise insecure regime via MBNLA. Compared to its physical counterpart, MBNLA not only is easier in term of implementation, but also allows one to achieve near optimal probability of success.

  1. The braided single-stage protocol for quantum secure communication

    NASA Astrophysics Data System (ADS)

    Darunkar, Bhagyashri; Verma, Pramode K.

    2014-05-01

    This paper presents the concept and implementation of a Braided Single-stage Protocol for quantum secure communication. The braided single-stage protocol is a multi-photon tolerant secure protocol. This multi-photon tolerant protocol has been implemented in the laboratory using free-space optics technology. The proposed protocol capitalizes on strengths of the three-stage protocol and extends it with a new concept of braiding. This protocol overcomes the limitations associated with the three-stage protocol in the following ways: It uses the transmission channel only once as opposed to three times in the three-stage protocol, and it is invulnerable to man-in-the-middle attack. This paper also presents the error analysis resulting from the misalignment of the devices in the implementation. The experimental results validate the efficient use of transmission resources and improvement in the data transfer rate.

  2. Ultimate classical communication rates of quantum optical channels

    NASA Astrophysics Data System (ADS)

    Giovannetti, V.; García-Patrón, R.; Cerf, N. J.; Holevo, A. S.

    2014-10-01

    Optical channels, such as fibres or free-space links, are ubiquitous in today's telecommunication networks. They rely on the electromagnetic field associated with photons to carry information from one point to another in space. A complete physical model of these channels must necessarily take quantum effects into account to determine their ultimate performances. Single-mode, phase-insensitive bosonic Gaussian channels have been extensively studied over past decades, given their importance for practical applications. In spite of this, a long-standing unsolved conjecture on the optimality of Gaussian encodings has prevented finding their classical communication capacity. Here, this conjecture is solved by proving that the vacuum state achieves the minimum output entropy of these channels. This establishes the ultimate achievable bit rate under an energy constraint, as well as the long awaited proof that the single-letter classical capacity of these channels is additive.

  3. Monolithic microwave integrated circuit technology for advanced space communication

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Romanofsky, Robert R.

    1988-01-01

    Future Space Communications subsystems will utilize GaAs Monolithic Microwave Integrated Circuits (MMIC's) to reduce volume, weight, and cost and to enhance system reliability. Recent advances in GaAs MMIC technology have led to high-performance devices which show promise for insertion into these next generation systems. The status and development of a number of these devices operating from Ku through Ka band will be discussed along with anticipated potential applications.

  4. Attitude Control Subsystem for the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Hewston, Alan W.; Mitchell, Kent A.; Sawicki, Jerzy T.

    1996-01-01

    This paper provides an overview of the on-orbit operation of the Attitude Control Subsystem (ACS) for the Advanced Communications Technology Satellite (ACTS). The three ACTS control axes are defined, including the means for sensing attitude and determining the pointing errors. The desired pointing requirements for various modes of control as well as the disturbance torques that oppose the control are identified. Finally, the hardware actuators and control loops utilized to reduce the attitude error are described.

  5. Advanced Communications Technology Satellite (ACTS): Four-Year System Performance

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.; Bauer, Robert; Krawczyk, Richard J.; Reinhart, Richard C.; Zernic, Michael J.; Gargione, Frank

    1999-01-01

    The Advanced Communications Technology Satellite (ACTS) was conceived at the National Aeronautics and Space Administration (NASA) in the late 1970's as a follow-on program to ATS and CTS to continue NASA's long history of satellite communications projects. The ACTS project set the stage for the C-band satellites that started the industry, and later the ACTS project established the use of Ku-band for video distribution and direct-to-home broadcasting. ACTS, launched in September 1993 from the space shuttle, created a revolution in satellite system architecture by using digital communications techniques employing key technologies such as a fast hopping multibeam antenna, an on-board baseband processor, a wide-band microwave switch matrix, adaptive rain fade compensation, and the use of 900 MHz transponders operating at Ka-band frequencies. This paper describes the lessons learned in each of the key ACTS technology areas, as well as in the propagation investigations.

  6. A Mobile Communications Space Link Between the Space Shuttle Orbiter and the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Fink, Patrick; Arndt, G. D.; Bondyopadhyay, P.; Shaw, Roland

    1994-01-01

    A communications experiment is described as a link between the Space Shuttle Orbiter (SSO) and the Advanced Communications Technology Satellite (ACTS). Breadboarding for this experiment has led to two items with potential for commercial application: a 1-Watt Ka-band amplifier and a Ka-band, circularly polarized microstrip antenna. Results of the hybrid Ka-band amplifier show gain at 30 dB and a saturated output power of 28.5 dBm. A second version comprised of MMIC amplifiers is discussed. Test results of the microstrip antenna subarray show a gain of approximately 13 dB and excellent circular polarization.

  7. Fault-tolerant controlled deterministic secure quantum communication using EPR states against collective noise

    NASA Astrophysics Data System (ADS)

    Kao, Shih-Hung; Yang, Chun-Wei; Hwang, Tzonelih

    2016-09-01

    This paper proposes two new fault-tolerant controlled deterministic secure quantum communication (CDSQC) protocols based only on Einstein-Podolsky-Rosen (EPR) entangled states. The proposed protocols are designed to be robust against the collective-dephasing noise and the collective-rotation noise, respectively. Compared to the existing fault-tolerant controlled quantum communication protocols, the proposed protocols not only can do without a quantum channel between the receiver and the controller as the state-of-the-art protocols do, but also have the advantage that the number of quantum particles required in the CDSQC protocols is reduced owing to the use of the simplest entangled states.

  8. Radiation-Hardened Electronics for Advanced Communications Systems

    NASA Technical Reports Server (NTRS)

    Whitaker, Sterling

    2015-01-01

    Novel approach enables high-speed special-purpose processors Advanced reconfigurable and reprogrammable communication systems will require sub-130-nanometer electronics. Legacy single event upset (SEU) radiation-tolerant circuits are ineffective at speeds greater than 125 megahertz. In Phase I of this project, ICs, LLC, demonstrated new base-level logic circuits that provide SEU immunity for sub-130-nanometer high-speed circuits. In Phase II, the company developed an innovative self-restoring logic (SRL) circuit and a system approach that provides high-speed, SEU-tolerant solutions that are effective for sub-130-nanometer electronics scalable to at least 22-nanometer processes. The SRL system can be used in the design of NASA's next-generation special-purpose processors, especially reconfigurable communication processors.

  9. Improved orthogonal frequency division multiplexing communications through advanced coding

    NASA Astrophysics Data System (ADS)

    Westra, Jeffrey; Patti, John

    2005-08-01

    Orthogonal Frequency Division Multiplexing (OFDM) is a communications technique that transmits a signal over multiple, evenly spaced, discrete frequency bands. OFDM offers some advantages over traditional, single-carrier modulation techniques, such as increased immunity to inter-symbol interference. For this reason OFDM is an attractive candidate for sensor network application; it has already been included in several standards, including Digital Audio Broadcast (DAB); digital television standards in Europe, Japan and Australia; asymmetric digital subscriber line (ASDL); and wireless local area networks (WLAN), specifically IEEE 802.11a. Many of these applications currently make use of a standard convolutional code with Viterbi decoding to perform forward error correction (FEC). Replacing such convolutional codes with advanced coding techniques using iterative decoding, such as Turbo codes, can substantially improve the performance of the OFDM communications link. This paper demonstrates such improvements using the 802.11a wireless LAN standard.

  10. Numerical simulation of linear and nonlinear quantum optics as a design tool for free-space quantum communications and quantum imaging

    NASA Astrophysics Data System (ADS)

    Meyers, Ronald E.; Deacon, Keith S.; Rosen, D.

    2002-12-01

    A new quantum optics tool for simulating quantum probability density functions resulting from the linear and nonlinear interaction of photons with atoms and with other photons is developed and presented. It can be used to design and simulate quantum optics experiments used in quantum communications, quantum computing, and quantum imaging. Examples of a photon interacting with linears systems of mirrors and beamsplitters are simulated. Nonlinear simulations of the interaction of three photons resulting in photon momentum entanglement is presented. The wavefunction is expanded in Fock states. Fock states cannot be represented by classical modeling and therefore, the results of our modeling can in general represent phenomena in both the linear and nonlinear cases which cannot be modeled by classical linear optics. The modeling presented here is more general than the classical linear optics. Models of atmospheric turbulence and their simulations are presented and demonstrate the potential for first principles physics quantum optics simulations through turbulence in realistic environments.

  11. Quantifying the Nonlocality of Greenberger-Horne-Zeilinger Quantum Correlations by a Bounded Communication Simulation Protocol

    NASA Astrophysics Data System (ADS)

    Branciard, Cyril; Gisin, Nicolas

    2011-07-01

    The simulation of quantum correlations with finite nonlocal resources, such as classical communication, gives a natural way to quantify their nonlocality. While multipartite nonlocal correlations appear to be useful resources, very little is known on how to simulate multipartite quantum correlations. We present a protocol that reproduces tripartite Greenberger-Horne-Zeilinger correlations with bounded communication: 3 bits in total turn out to be sufficient to simulate all equatorial Von Neumann measurements on the tripartite Greenberger-Horne-Zeilinger state.

  12. Quantifying the nonlocality of Greenberger-Horne-Zeilinger quantum correlations by a bounded communication simulation protocol.

    PubMed

    Branciard, Cyril; Gisin, Nicolas

    2011-07-01

    The simulation of quantum correlations with finite nonlocal resources, such as classical communication, gives a natural way to quantify their nonlocality. While multipartite nonlocal correlations appear to be useful resources, very little is known on how to simulate multipartite quantum correlations. We present a protocol that reproduces tripartite Greenberger-Horne-Zeilinger correlations with bounded communication: 3 bits in total turn out to be sufficient to simulate all equatorial Von Neumann measurements on the tripartite Greenberger-Horne-Zeilinger state.

  13. Quantum secure direct communication of digital and analog signals using continuum coherent states

    NASA Astrophysics Data System (ADS)

    Guerra, Antônio Geovan de Araújo Holanda; Rios, Francisco Franklin Sousa; Ramos, Rubens Viana

    2016-08-01

    In this work, we present optical schemes for secure direct quantum communication of digital and analog signals using continuum coherent states and frequency-dependent phase modulation. The main advantages of the proposed schemes are that they do not use entangled states and they can be implemented with today technology. The theory of quantum interference of continuum coherent state is described, and the optical setups for secure direct communication are presented and their securities are discussed.

  14. Advanced Communications Technology Satellite Now Operating in an Inclined Orbit

    NASA Technical Reports Server (NTRS)

    Bauer, Robert A.

    1999-01-01

    The Advanced Communications Technology Satellite (ACTS) system has been modified to support operation in an inclined orbit that is virtually transparent to users, and plans are to continue this final phase of its operation through September 2000. The next 2 years of ACTS will provide a new opportunity for using the technologies that this system brought online over 5 years ago and that are still being used to resolve the technical issues that face NASA and the satellite industry in the area of seamless networking and interoperability with terrestrial systems. New goals for ACTS have been defined that align the program with recent changes in NASA and industry. ACTS will be used as a testbed to: Show how NASA and other Government agencies can use commercial systems for 1. future support of their operations Test, characterize, and resolve technical issues in using advanced communications 2. protocols such as asynchronous transfer mode (ATM) and transmission control protocol/Internet protocol (TCP/IP) over long latency links as found when interoperating satellites with terrestrial systems Evaluate narrow-spot-beam Ka-band satellite operation in an inclined orbit 3. Verify Ka-band satellite technologies since no other Ka-band system is yet 4. available in the United States

  15. The Dining Cryptographer Problem-Based Anonymous Quantum Communication via Non-maximally Entanglement State Analysis

    NASA Astrophysics Data System (ADS)

    Shi, Ronghua; Su, Qian; Guo, Ying; Huang, Dazu

    2013-02-01

    We demonstrate an anonymous quantum communication (AQC) via the non-maximally entanglement state analysis (NESA) based on the dining cryptographer problem (DCP). The security of the present AQC is ensured due to the quantum-mechanical impossibility of local unitary transformations between non-maximally entanglement states, which provides random numbers for the secure AQC. The analysis shows that the DCP-based AQC can be performed without intractability through the NESA in the multi-photon entangled quantum system.

  16. Use of advanced solar cells for commercial communication satellites

    NASA Astrophysics Data System (ADS)

    Bailey, Sheila G.; Landis, Geoffrey A.

    1995-03-01

    The current generation of communications satellites are located primarily in geosynchronous Earth orbit (GEO). Over the next decade, however, a new generation of communications satellites will be built and launched, designed to provide a world-wide interconnection of portable telephones. For this mission, the satellites must be positioned in lower polar and near-polar orbits. To provide complete coverage, large numbers of satellites will be required. Because the required number of satellites decreases as the orbital altitude is increased, fewer satellites would be required if the orbit chosen were raised from low to intermediate orbit. However, in intermediate orbits, satellites encounter significant radiation due to trapped electrons and protons. Radiation tolerant solar cells may be necessary to make such satellites feasible. We analyze the amount of radiation encountered in low and intermediate polar orbits at altitudes of interest to next-generation communication satellites, calculate the expected degradation for silicon, GaAs, and InP solar cells, and show that the lifetimes can be significantly increased by use of advanced solar cells.

  17. Use of advanced solar cells for commerical communication satellites

    NASA Astrophysics Data System (ADS)

    Landis, Geoffrey A.; Bailey, Sheila G.

    1995-01-01

    The current generation of communications satellites are located primarily in geosynchronous Earth orbit (GEO). Over the next decade, however, a new generation of communications satellites will be built and launched, designed to provide a world-wide interconnection of portable telephones. For this mission, the satellites must be positioned in lower polar- and near-polar orbits. To provide complete coverage, large numbers of satellites will be required. Because of the required number of satellites decreases as the orbital altitude is increased, fewer satellites would be required if the orbit chosen were raised from Low to intermediate orbit. However, in intermediate orbits, satellites encounter significant radiation due to trapped electrons and protons. Radiation tolerant solar cells may be necessary to make such satellites feasible. We analyze the amount of radiation encountered in low and intermediate polar orbits at altitudes of interest to next-generation communication satellites, calculate the expected degradation for silicon, GaAs, and InP solar cells, and show that the lifetimes can be significantly increased by use of advanced solar cells.

  18. Discord as a quantum resource for bi-partite communication

    SciTech Connect

    Chrzanowski, Helen M.; Assad, Syed M.; Symul, Thomas; Lam, Ping Koy; Gu, Mile; Modi, Kavan; Vedral, Vlatko; Ralph, Timothy C.

    2014-12-04

    Coherent interactions that generate negligible entanglement can still exhibit unique quantum behaviour. This observation has motivated a search beyond entanglement for a complete description of all quantum correlations. Quantum discord is a promising candidate. Here, we experimentally demonstrate that under certain measurement constraints, discord between bipartite systems can be consumed to encode information that can only be accessed by coherent quantum interactions. The inability to access this information by any other means allows us to use discord to directly quantify this ‘quantum advantage’.

  19. Secure multi-party communication with quantum key distribution managed by trusted authority

    DOEpatents

    Hughes, Richard John; Nordholt, Jane Elizabeth; Peterson, Charles Glen

    2015-01-06

    Techniques and tools for implementing protocols for secure multi-party communication after quantum key distribution ("QKD") are described herein. In example implementations, a trusted authority facilitates secure communication between multiple user devices. The trusted authority distributes different quantum keys by QKD under trust relationships with different users. The trusted authority determines combination keys using the quantum keys and makes the combination keys available for distribution (e.g., for non-secret distribution over a public channel). The combination keys facilitate secure communication between two user devices even in the absence of QKD between the two user devices. With the protocols, benefits of QKD are extended to multi-party communication scenarios. In addition, the protocols can retain benefit of QKD even when a trusted authority is offline or a large group seeks to establish secure communication within the group.

  20. Secure multi-party communication with quantum key distribution managed by trusted authority

    DOEpatents

    Nordholt, Jane Elizabeth; Hughes, Richard John; Peterson, Charles Glen

    2013-07-09

    Techniques and tools for implementing protocols for secure multi-party communication after quantum key distribution ("QKD") are described herein. In example implementations, a trusted authority facilitates secure communication between multiple user devices. The trusted authority distributes different quantum keys by QKD under trust relationships with different users. The trusted authority determines combination keys using the quantum keys and makes the combination keys available for distribution (e.g., for non-secret distribution over a public channel). The combination keys facilitate secure communication between two user devices even in the absence of QKD between the two user devices. With the protocols, benefits of QKD are extended to multi-party communication scenarios. In addition, the protocols can retain benefit of QKD even when a trusted authority is offline or a large group seeks to establish secure communication within the group.

  1. Advances toward high spectral resolution quantum X-ray calorimetry

    NASA Technical Reports Server (NTRS)

    Moseley, S. H.; Kelley, R. L.; Schoelkopf, R. J.; Szymkowiak, A. E.; Mccammon, D.

    1988-01-01

    Thermal detectors for X-ray spectroscopy combining high spectral resolution and quantum efficiency have been developed. These microcalorimeters measure the energy released in the absorption of a single photon by sensing the rise in temperature of a small absorbing structure. The ultimate energy resolution of such a device is limited by the thermodynamic power fluctuations in the thermal link between the calorimeter and isothermal bath and can in principle be made as low as 1 eV. The performance of a real device is degraded due to noise contributions such as excess 1/f noise in the thermistor and incomplete conversion of energy into phonons. The authors report some recent advances in thermometry, X-ray absorption and thermalization, fabrication techniques, and detector optimization in the presence of noise. These improvements have resulted in a device with a spectral resolution of 17 eV FWHM, measured at 6 keV.

  2. Detection and compensation of basis deviation in satellite-to-ground quantum communications.

    PubMed

    Zhang, Ming; Zhang, Liang; Wu, Jincai; Yang, Shiji; Wan, Xiong; He, Zhiping; Jia, Jianjun; Citrin, D S; Wang, Jianyu

    2014-04-21

    Basis deviation is the reference-frame deviation between a sender and receiver caused by satellite motion in satellite-to-ground quantum communications. It increases the quantum-bit error ratio of the system and must be compensated for to guarantee reliable quantum communications. We present a new scheme for compensating for basis deviation that employs a BB84 decoding module to detect basis deviation and half-wave plate to provide compensation. Based on this detection scheme, we design a basis-deviation compensation approach and test its feasibility in a voyage experiment. Unlike other polarization-correction schemes, this compensation scheme is simple, convenient, and can be easily implemented in satellite-to-ground quantum communications without increased burden to the satellite. PMID:24787870

  3. Detection and compensation of basis deviation in satellite-to-ground quantum communications.

    PubMed

    Zhang, Ming; Zhang, Liang; Wu, Jincai; Yang, Shiji; Wan, Xiong; He, Zhiping; Jia, Jianjun; Citrin, D S; Wang, Jianyu

    2014-04-21

    Basis deviation is the reference-frame deviation between a sender and receiver caused by satellite motion in satellite-to-ground quantum communications. It increases the quantum-bit error ratio of the system and must be compensated for to guarantee reliable quantum communications. We present a new scheme for compensating for basis deviation that employs a BB84 decoding module to detect basis deviation and half-wave plate to provide compensation. Based on this detection scheme, we design a basis-deviation compensation approach and test its feasibility in a voyage experiment. Unlike other polarization-correction schemes, this compensation scheme is simple, convenient, and can be easily implemented in satellite-to-ground quantum communications without increased burden to the satellite.

  4. Field test of a practical secure communication network with decoy-state quantum cryptography.

    PubMed

    Chen, Teng-Yun; Liang, Hao; Liu, Yang; Cai, Wen-Qi; Ju, Lei; Liu, Wei-Yue; Wang, Jian; Yin, Hao; Chen, Kai; Chen, Zeng-Bing; Peng, Cheng-Zhi; Pan, Jian-Wei

    2009-04-13

    We present a secure network communication system that operated with decoy-state quantum cryptography in a real-world application scenario. The full key exchange and application protocols were performed in real time among three nodes, in which two adjacent nodes were connected by approximate 20 km of commercial telecom optical fiber. The generated quantum keys were immediately employed and demonstrated for communication applications, including unbreakable real-time voice telephone between any two of the three communication nodes, or a broadcast from one node to the other two nodes by using one-time pad encryption.

  5. Field test of a practical secure communication network with decoy-state quantum cryptography.

    PubMed

    Chen, Teng-Yun; Liang, Hao; Liu, Yang; Cai, Wen-Qi; Ju, Lei; Liu, Wei-Yue; Wang, Jian; Yin, Hao; Chen, Kai; Chen, Zeng-Bing; Peng, Cheng-Zhi; Pan, Jian-Wei

    2009-04-13

    We present a secure network communication system that operated with decoy-state quantum cryptography in a real-world application scenario. The full key exchange and application protocols were performed in real time among three nodes, in which two adjacent nodes were connected by approximate 20 km of commercial telecom optical fiber. The generated quantum keys were immediately employed and demonstrated for communication applications, including unbreakable real-time voice telephone between any two of the three communication nodes, or a broadcast from one node to the other two nodes by using one-time pad encryption. PMID:19365479

  6. A Multiparty Controlled Bidirectional Quantum Secure Direct Communication and Authentication Protocol Based on EPR Pairs

    NASA Astrophysics Data System (ADS)

    Chang, Yan; Zhang, Shi-Bin; Yan, Li-Li; Sheng, Zhi-Wei

    2013-06-01

    A multiparty controlled bidirectional quantum secure direct communication and authentication protocol is proposed based on EPR pair and entanglement swapping. The legitimate identities of communicating parties are encoded to Bell states which act as a detection sequence. Secret messages are transmitted by using the classical XOR operation, which serves as a one-time-pad. No photon with secret information transmits in the quantum channel. Compared with the protocols proposed by Wang et al. [Acta Phys. Sin. 56 (2007) 673; Opt. Commun. 266 (2006) 732], the protocol in this study implements bidirectional communication and authentication, which defends most attacks including the ‘man-in-the-middle’ attack efficiently.

  7. NASA ACTS Multibeam Antenna (MBA) System. [Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Choung, Youn H.; Stiles, W. Herschel; Wu, Joseph; Wong, William C.; Chen, C. Harry

    1986-01-01

    The design of the Advanced Communications Technology Satellite MBA system, which provides both spot beam and scanning beam coverage to both high and low burst rates data-users is examined. The MBA consists of receive and transmit antennas installed on a common precision mounting platform that is integrated to the bus through three flexures; a lightweight system with low thermal distortion is obtained by using composite materials for the MBA structures. The RF design, which is a Cassegrain reflector with a large equivalent focal length/aperture size, is described. Consideration is given to the position of the feed in order to minimize scan loss and sidelobe levels, the size of the subreflector in order to minimize feed spillover, and antenna performance degradation caused by reflector surface distortion. Breadbroad model test result reveal that the maximum sidelobe level outside the 2.5 HPBW region is -30 dB or lower relative to the power.

  8. Advancing Information and Communication Technology Knowledge for Undergraduate Nursing Students

    PubMed Central

    Procter, Paula M

    2012-01-01

    Nursing is a dynamic profession; for registered nurses their role is increasingly requiring greater information process understanding and the effective management of information to ensure high quality safe patient care. This paper outlines the design and implementation of Systems of eCare. This is a course which advances information and communication technology knowledge for undergraduate nursing students within a Faculty of Health and Wellbeing appropriately preparing nurses for their professional careers. Systems of eCare entwines throughout the three year programme mapping to the curriculum giving meaning to learning for the student. In conclusion comments from students convey their appreciation of the provision of this element of the undergraduate programme. PMID:24199114

  9. Study of repeater technology for advanced multifunctional communications satellites

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Investigations are presented concerning design concepts and implementation approaches for the satellite communication repeater subsystems of advanced multifunctional satellites. In such systems the important concepts are the use of multiple antenna beams, repeater switching (routing), and efficient spectrum utilization through frequency reuse. An information base on these techniques was developed and tradeoff analyses were made of repeater design concepts, with the work design taken in a broad sense to include modulation beam coverage patterns. There were five major areas of study: requirements analysis and processing; study of interbeam interference in multibeam systems; characterization of multiple-beam switching repeaters; estimation of repeater weight and power for a number of alternatives; and tradeoff analyses based on these weight and power data.

  10. Experiments applications guide: Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    1988-01-01

    This applications guide first surveys the capabilities of the Advanced Communication Technology Satellite (ACTS) system (both the flight and ground segments). This overview is followed by a description of the baseband processor (BBP) and microwave switch matrix (MSM) operating modes. Terminals operating with the baseband processor are referred to as low burst rate (LBR); and those operating with the microwave switch matrix, as high burst rate (HBR). Three very small-aperture terminals (VSATs), LBR-1, LBR-2, and HBR, are described for various ACTS operating modes. Also described is the NASA Lewis link evaluation terminal. A section on ACTS experiment opportunities introduces a wide spectrum of network control, telecommunications, system, and scientific experiments. The performance of the VSATs is discussed in detail. This guide is intended as a catalyst to encourage participation by the telecommunications, business, and science communities in a broad spectrum of experiments.

  11. Advanced information processing system: Inter-computer communication services

    NASA Technical Reports Server (NTRS)

    Burkhardt, Laura; Masotto, Tom; Sims, J. Terry; Whittredge, Roy; Alger, Linda S.

    1991-01-01

    The purpose is to document the functional requirements and detailed specifications for the Inter-Computer Communications Services (ICCS) of the Advanced Information Processing System (AIPS). An introductory section is provided to outline the overall architecture and functional requirements of the AIPS and to present an overview of the ICCS. An overview of the AIPS architecture as well as a brief description of the AIPS software is given. The guarantees of the ICCS are provided, and the ICCS is described as a seven-layered International Standards Organization (ISO) Model. The ICCS functional requirements, functional design, and detailed specifications as well as each layer of the ICCS are also described. A summary of results and suggestions for future work are presented.

  12. The Advanced Communications Technology Satellite - Performance, Reliability and Lessons Learned

    NASA Technical Reports Server (NTRS)

    Krawczyk, Richard J.; Ignaczak, Louis R.

    2000-01-01

    The Advanced Communications Satellite (ACTS) was conceived and developed in the mid- 1980s as an experimental satellite to demonstrate unproven Ka-band technology, and potential new commercial applications and services. Since launch into geostationary orbit in September 1993. ACTS has accumulated almost seven years of essentially trouble-free operation and met all program objectives. The unique technology, service experiments. and system level demonstrations accomplished by ACTS have been reported in many forums over the past several years. As ACTS completes its final experiments activity, this paper will relate the top-level program goals that have been achieved in the design, operation, and performance of the particular satellite subsystems. Pre-launch decisions to ensure satellite reliability and the subsequent operational experiences contribute to lessons learned that may be applicable to other comsat programs.

  13. Proceedings of the Advanced Communications Technology Satellite (ACTS) Conference 2000

    NASA Technical Reports Server (NTRS)

    Bauer, Robert (Editor); Derwae, Robert (Editor)

    2000-01-01

    The ACTS experiments program, which began in December 1993 and consisted of 103 different experiments, has made significant contributions to minimizing the risk of advanced satellite communications technology. The ACTS Conference 2000 (AC2000) was held to report the results of the program since the last ACTS conference was held in 1995 and to celebrate the end of a very successful satellite program. The conference was held on May 31, 2000, as part of the 6th Ka-band Utilization Conference in Cleveland, Ohio. Approximately 280 representatives of industry, academia, and government attended. The conference was organized into two parts: a technical session during the day and an evening reception. During the day, a series of five technical sessions included presentations of 17 papers covering the results of the experiment activity and technical performance of the satellite. In the evening, a reception was held to celebrate the end of the ACTS Experiments Program on one of NASA's most successful experimental communications satellite. These proceedings were developed to capture the entire event, including the evening reception.

  14. Innovative Networking Concepts Tested on the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Friedman, Daniel; Gupta, Sonjai; Zhang, Chuanguo; Ephremides, Anthony

    1996-01-01

    This paper describes a program of experiments conducted over the advanced communications technology satellite (ACTS) and the associated TI-VSAT (very small aperture terminal). The experiments were motivated by the commercial potential of low-cost receive only satellite terminals that can operate in a hybrid network environment, and by the desire to demonstrate frame relay technology over satellite networks. The first experiment tested highly adaptive methods of satellite bandwidth allocation in an integrated voice-data service environment. The second involved comparison of forward error correction (FEC) and automatic repeat request (ARQ) methods of error control for satellite communication with emphasis on the advantage that a hybrid architecture provides, especially in the case of multicasts. Finally, the third experiment demonstrated hybrid access to databases and compared the performance of internetworking protocols for interconnecting local area networks (LANs) via satellite. A custom unit termed frame relay access switch (FRACS) was developed by COMSAT Laboratories for these experiments; the preparation and conduct of these experiments involved a total of 20 people from the University of Maryland, the University of Colorado and COMSAT Laboratories, from late 1992 until 1995.

  15. Advanced MEMS systems for optical communication and imaging

    NASA Astrophysics Data System (ADS)

    Horenstein, M. N.; Stewart, J. B.; Cornelissen, S.; Sumner, R.; Freedman, D. S.; Datta, M.; Kani, N.; Miller, P.

    2011-06-01

    Optical communication and adaptive optics have emerged as two important uses of micro-electromechanical (MEMS) devices based on electrostatic actuation. Each application uses a mirror whose surface is altered by applying voltages of up to 300 V. Previous generations of adaptive-optic mirrors were large (~1 m) and required the use of piezoelectric transducers. Beginning in the mid-1990s, a new class of small MEMS mirrors (~1 cm) were developed. These mirrors are now a commercially available, mature technology. This paper describes three advanced applications of MEMS mirrors. The first is a mirror used for corona-graphic imaging, whereby an interferometric telescope blocks the direct light from a distant star so that nearby objects such as planets can be seen. We have developed a key component of the system: a 144-channel, fully-scalable, high-voltage multiplexer that reduces power consumption to only a few hundred milliwatts. In a second application, a MEMS mirror comprises part of a two-way optical communication system in which only one node emits a laser beam. The other node is passive, incorporating a retro-reflective, electrostatic MEMS mirror that digitally encodes the reflected beam. In a third application, the short (~100-ns) pulses of a commercially-available laser rangefinder are returned by the MEMS mirror as a digital data stream. Suitable low-power drive systems comprise part of the system design.

  16. Data communication requirements for the advanced NAS network

    NASA Technical Reports Server (NTRS)

    Levin, Eugene; Eaton, C. K.; Young, Bruce

    1986-01-01

    The goal of the Numerical Aerodynamic Simulation (NAS) Program is to provide a powerful computational environment for advanced research and development in aeronautics and related disciplines. The present NAS system consists of a Cray 2 supercomputer connected by a data network to a large mass storage system, to sophisticated local graphics workstations, and by remote communications to researchers throughout the United States. The program plan is to continue acquiring the most powerful supercomputers as they become available. In the 1987/1988 time period it is anticipated that a computer with 4 times the processing speed of a Cray 2 will be obtained and by 1990 an additional supercomputer with 16 times the speed of the Cray 2. The implications of this 20-fold increase in processing power on the data communications requirements are described. The analysis was based on models of the projected workload and system architecture. The results are presented together with the estimates of their sensitivity to assumptions inherent in the models.

  17. Communication: Spin-free quantum computational simulations and symmetry adapted states.

    PubMed

    Whitfield, James Daniel

    2013-07-14

    The ideas of digital simulation of quantum systems using a quantum computer parallel the original ideas of numerical simulation using a classical computer. In order for quantum computational simulations to advance to a competitive point, many techniques from classical simulations must be imported into the quantum domain. In this article, we consider the applications of symmetry in the context of quantum simulation. Building upon well established machinery, we propose a form of first quantized simulation that only requires the spatial part of the wave function, thereby allowing spin-free quantum computational simulations. We go further and discuss the preparation of N-body states with specified symmetries based on projection techniques. We consider two simple examples, molecular hydrogen and cyclopropenyl cation, to illustrate the ideas. The methods here are the first to explicitly deal with preparing N-body symmetry-adapted states and open the door for future investigations into group theory, chemistry, and quantum simulation. PMID:23862919

  18. Communication: Spin-free quantum computational simulations and symmetry adapted states.

    PubMed

    Whitfield, James Daniel

    2013-07-14

    The ideas of digital simulation of quantum systems using a quantum computer parallel the original ideas of numerical simulation using a classical computer. In order for quantum computational simulations to advance to a competitive point, many techniques from classical simulations must be imported into the quantum domain. In this article, we consider the applications of symmetry in the context of quantum simulation. Building upon well established machinery, we propose a form of first quantized simulation that only requires the spatial part of the wave function, thereby allowing spin-free quantum computational simulations. We go further and discuss the preparation of N-body states with specified symmetries based on projection techniques. We consider two simple examples, molecular hydrogen and cyclopropenyl cation, to illustrate the ideas. The methods here are the first to explicitly deal with preparing N-body symmetry-adapted states and open the door for future investigations into group theory, chemistry, and quantum simulation.

  19. Practical Quantum Cryptography for Secure Free-Space Communications

    SciTech Connect

    Buttler, W.T.; Hughes, R.J.; Kwiat, P.G.; Lamoreaux, S.K.; Morgan, G.L.; Nordholt, J.E.; Peterson, C.G.

    1999-02-01

    Quantum cryptography is an emerging technology in which two parties may simultaneously generate shared, secret cryptographic key material using the transmission of quantum states of light. The security of these transmissions is based on the inviolability of the laws of quantum mechanics and information-theoretically secure post-processing methods. An adversary can neither successfully tap the quantum transmissions, nor evade detection, owing to Heisenberg's uncertainty principle. In this paper we describe the theory of quantum cryptography, and the most recent results from our experimental free-space system with which we have demonstrated for the first time the feasibility of quantum key generation over a point-to-point outdoor atmospheric path in daylight. We achieved a transmission distance of 0.5 km, which was limited only by the length of the test range. Our results provide strong evidence that cryptographic key material could be generated on demand between a ground station and a satellite (or between two satellites), allowing a satellite to be securely re-keyed on orbit. We present a feasibility analysis of surface-to-satellite quantum key generation.

  20. On the quantum-channel capacity for orbital angular momentum-based free-space optical communications.

    PubMed

    Zhang, Yequn; Djordjevic, Ivan B; Gao, Xin

    2012-08-01

    Inspired by recent demonstrations of orbital angular momentum-(OAM)-based single-photon communications, we propose two quantum-channel models: (i) the multidimensional quantum-key distribution model and (ii) the quantum teleportation model. Both models employ operator-sum representation for Kraus operators derived from OAM eigenkets transition probabilities. These models are highly important for future development of quantum-error correction schemes to extend the transmission distance and improve date rates of OAM quantum communications. By using these models, we calculate corresponding quantum-channel capacities in the presence of atmospheric turbulence.

  1. On the quantum-channel capacity for orbital angular momentum-based free-space optical communications.

    PubMed

    Zhang, Yequn; Djordjevic, Ivan B; Gao, Xin

    2012-08-01

    Inspired by recent demonstrations of orbital angular momentum-(OAM)-based single-photon communications, we propose two quantum-channel models: (i) the multidimensional quantum-key distribution model and (ii) the quantum teleportation model. Both models employ operator-sum representation for Kraus operators derived from OAM eigenkets transition probabilities. These models are highly important for future development of quantum-error correction schemes to extend the transmission distance and improve date rates of OAM quantum communications. By using these models, we calculate corresponding quantum-channel capacities in the presence of atmospheric turbulence. PMID:22859154

  2. Quantum Steganography for Multi-party Covert Communication

    NASA Astrophysics Data System (ADS)

    Liu, Lin; Tang, Guang-Ming; Sun, Yi-Feng; Yan, Shu-Fan

    2016-01-01

    A novel multi-party quantum steganography protocol based on quantum secret sharing is proposed in this paper. Hidden channels are built in HBB and improved HBB quantum secret sharing protocols for secret messages transmitting, via the entanglement swapping of GHZ states and Bell measurement. Compared with the original protocol, there are only a few different GHZ sates transmitted in the proposed protocol, making the hidden channel with good imperceptibility. Moreover, the secret messages keep secure even when the hidden channel is under the attack from the dishonest participators, for the sub-secretmessages distributed randomly to different participators. With good imperceptibility and security, the capacity of proposed protocol is higher than previous multi-party quantum steganography protocol.

  3. Security of quantum key distribution with a laser reference coherent state, resistant to loss in the communication channel

    NASA Astrophysics Data System (ADS)

    Molotkov, S. N.; Potapova, T. A.

    2015-06-01

    The problem of quantum key distribution security in channels with large losses is still open. Quasi-single-photon sources of quantum states with losses in the quantum communication channel open up the possibility of attacking with unambiguous state discrimination (USD) measurements, resulting in a loss of privacy. In this letter, the problem is solved by counting the classic reference pulses. Conservation of the number of counts of intense coherent pulses makes it impossible to conduct USD measurements. Moreover, the losses in the communication channel are considered to be unknown in advance and are subject to change throughout the series parcels. Unlike other protocols, differential phase shift (Inoue et al 2002 Phys. Rev. Lett. 89 037902, Inoue et al 2003 Phys. Rev. A 68 022317, Takesue et al 2007 Nat. Photon. 1 343, Wen et al 2009 Phys. Rev. Lett. 103 170503) and coherent one way (Stucki et al 2005 Appl. Phys. Lett. 87 194108, Branciard et al 2005 Appl. Phys. Lett. 87 194108, Branciard et al 2008 New J. Phys. 10 013031, Stucki et al 2008 Opt. Express 17 13326), the simplicity of the protocol makes it possible to carry out a complete analysis of its security.

  4. Relativistic Quantum Communication and the Structure of Spacetime

    NASA Astrophysics Data System (ADS)

    Martin-Martinez, Eduardo

    We study the transmission of information and correlations through quantum fields in cosmological backgrounds. With this aim, we make use of quantum information tools to quantify the classical and quantum correlations induced by a quantum massless scalar field in two particle detectors, one located in the early universe (Alice's) and the other located at a later time (Bob's). In particular, we focus on two phenomena: a) the consequences on the transmission of information of the violations of the strong Huygens principle for quantum fields, and b) the analysis of the field vacuum correlations via correlation harvesting from Alice to Bob. We will study a standard cosmological model first and then assess whether these results also hold if we use other than the general relativistic dynamics. As a particular example, we will study the transmission of information through the Big Bounce, that replaces the Big Bang, in the effective dynamics of Loop Quantum Cosmology. We show that much more information reaches us through timelike channels (not mediated by real photons) than it is carried by rays of light, which are usually regarded as the only carriers of information.

  5. Fluorescence correlation spectroscopy using quantum dots: advances, challenges and opportunities.

    PubMed

    Heuff, Romey F; Swift, Jody L; Cramb, David T

    2007-04-28

    Semiconductor nanocrystals (quantum dots) have been increasingly employed in measuring the dynamic behavior of biomacromolecules using fluorescence correlation spectroscopy. This poses a challenge, because quantum dots display their own dynamic behavior in the form of intermittent photoluminescence, also known as blinking. In this review, the manifestation of blinking in correlation spectroscopy will be explored, preceded by an examination of quantum dot blinking in general.

  6. Quantum secure direct communication network with superdense coding and decoy photons

    NASA Astrophysics Data System (ADS)

    Deng, Fu-Guo; Li, Xi-Han; Li, Chun-Yan; Zhou, Ping; Zhou, Hong-Yu

    2007-07-01

    A quantum secure direct communication network scheme is proposed with quantum superdense coding and decoy photons. The servers on a passive optical network prepare and measure the quantum signal, i.e. a sequence of the d-dimensional Bell states. After confirming the security of the photons received from the receiver, the sender codes his secret message on them directly. For preventing a dishonest server from eavesdropping, some decoy photons prepared by measuring one photon in the Bell states are used to replace some original photons. One of the users on the network can communicate to any other one. This scheme has the advantage of high capacity, and it is more convenient than others as only a sequence of photons is transmitted in quantum line.

  7. Characterizing the performance of waveguide technologies for microwave-frequency quantum communication

    NASA Astrophysics Data System (ADS)

    Kurpiers, Philipp; Frey, Tobias; Wallraff, Andreas

    In circuit quantum electrodynamics (QED) systems quantum communication over distances beyond chip-scale requires low-loss waveguides. We measure the loss per unit length and the phase stability of commercially available waveguide technologies down to Millikelvin temperatures and single photon levels. More specifically, we characterize the frequency dependent attenuation and dispersion properties of a range of semi-rigid microwave cables and waveguides. We study the properties of various, commonly used conducting and dielectric materials with high accuracy in resonant structures to extract the internal quality factor which is inversely proportional to the loss per unit length. Furthermore, we compare our data with corresponding loss models. The results of our characterization are relevant to applications in which quantum communication is needed between nodes of a small network, e.g. between quantum circuits realized on different chips within the same or in distinct cryogenic systems.

  8. Cryptanalysis and improvement of a quantum communication-based online shopping mechanism

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Yang, Ying-Hui; Jia, Heng-Yue

    2015-06-01

    Recently, Chou et al. (Electron Commer Res 14:349-367, 2014) presented a novel controlled quantum secure direct communication protocol which can be used for online shopping. The authors claimed that their protocol was immune to the attacks from both external eavesdropper and internal betrayer. However, we find that this protocol is vulnerable to the attack from internal betrayer. In this paper, we analyze the security of this protocol to show that the controller in this protocol is able to eavesdrop the secret information of the sender (i.e., the customer's shopping information), which indicates that it cannot be used for secure online shopping as the authors expected. Accordingly, an improvement of this protocol, which could resist the controller's attack, is proposed. In addition, we present another protocol which is more appropriate for online shopping. Finally, a discussion about the difference in detail of the quantum secure direct communication process between regular quantum communications and online shopping is given.

  9. Experimental quantum secret sharing and third-man quantum cryptography.

    PubMed

    Chen, Yu-Ao; Zhang, An-Ning; Zhao, Zhi; Zhou, Xiao-Qi; Lu, Chao-Yang; Peng, Cheng-Zhi; Yang, Tao; Pan, Jian-Wei

    2005-11-11

    Quantum secret sharing (QSS) and third-man quantum cryptography (TQC) are essential for advanced quantum communication; however, the low intensity and fragility of the multiphoton entanglement source in previous experiments have made their realization an extreme experimental challenge. Here, we develop and exploit an ultrastable high intensity source of four-photon entanglement to report an experimental realization of QSS and TQC. The technology developed in our experiment will be important for future multiparty quantum communication.

  10. Quantum correlations in Newtonian space and time: arbitrarily fast communication or nonlocality

    NASA Astrophysics Data System (ADS)

    Gisin, Nicolas

    2013-03-01

    Experimental violations of Bell inequalities using space-like separated measurements precludes the explanation of quantum correlations through causal influences propagating at subluminal speed. Yet, ``everything looks as if the two parties somehow communicate behind the scene.'' We investigate the assumption that they do so at a speed faster than light, though finite. Such an assumption doesn't respect the spirit of Einstein relativity. However, it is not crystal clear that such ``communication behind the scene'' would contradict relativity. Indeed, one could imagine that this communication remains for ever hidden to humans, i.e. that it could not be controlled by humans, only Nature exploits it to produce correlations that can't be explained by usual common causes. To define faster than light hidden communication requires a universal privileged reference frame in which this faster than light speed is defined. Again, such a universal privileged frame is not in the spirit of relativity, but it is also clearly not in contradiction: for example the reference frame in which the cosmic microwave background radiation is isotropic defines such a privileged frame. Hence, a priori, a hidden communication explanation is not more surprising than nonlocality. We prove that for any finite speed, such models predict correlations that can be exploited for faster-than-light communication. This superluminal communication doesn't require access to any hidden physical quantities, but only the manipulation of measurement devices at the level of our present-day description of quantum experiments. Consequently, all possible explanations of quantum correlations that satisfy the principle of continuity, which states that everything propagates gradually and continuously through space and time, or in other words, all combination of local common causes and direct causes that reproduce quantum correlations, lead to faster than light communication. Accordingly, either there is superluminal

  11. Advanced optical fiber communication simulations in electrotechnical engineering education

    NASA Astrophysics Data System (ADS)

    Vervaeke, Michael; Nguyen Thi, Cac; Thienpont, Hugo

    2004-10-01

    We present our efforts in education to apply advanced optical communication simulation software into our Electrical Engineering curriculum by implementing examples from theoretical courses with commercially available simulation software. Photonic design software is an interesting tool for the education of Engineers: these tools are able to simulate a huge variety of photonic components without major investments in student lab hardware. Moreover: some exotic phenomena ,which would usually involve specialty hardware, can be taught. We chose to implement VPItransmissionMaker from VPIsystems in the lab exercises for graduating Electrotechnical Engineers with majors in Photonics. The guideline we develop starts with basic examples provided by VPIsystems. The simplified simulation schemes serve as an introduction to the simulation techniques. Next, we highlight examples from the theoretical courses on Optical Telecommunications. A last part is an assignment where students have to design and simulate a system using real life component datasheets. The aim is to train them to interpret datasheets, to make design choices for their optical fiber system and to enhance their management skills. We detail our approach, highlight the educational aspects, the insight gained by the students, and illustrate our method with different examples.

  12. Gigabit Satellite Network for NASA's Advanced Communication Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Hoder, Douglas; Bergamo, Marcos

    1996-01-01

    The advanced communication technology satellite (ACTS) gigabit satellite network provides long-haul point-to-point and point-to-multipoint full-duplex SONET services over NASA's ACTS. at rates up to 622 Mbit/s (SONET OC-12), with signal quality comparable to that obtained with terrestrial fiber networks. Data multiplexing over the satellite is accomplished using time-division multiple access (TDMA) techniques coordinated with the switching and beam hopping facilities provided by ACTS. Transmissions through the satellite are protected with Reed-Solomon encoding. providing virtually error-free transmission under most weather conditions. Unique to the system are a TDMA frame structure and satellite synchronization mechanism that allow: (a) very efficient utilization of the satellite capacity: (b) over-the-satellite dosed-loop synchronization of the network in configurations with up to 64 ground stations: and (c) ground station initial acquisition without collisions with existing signalling or data traffic. The user interfaces are compatible with SONET standards, performing the function of conventional SONET multiplexers and. as such. can be: readily integrated with standard SONET fiber-based terrestrial networks. Management of the network is based upon the simple network management protocol (SNMP). and includes an over-the-satellite signalling network and backup terrestrial internet (IP-based) connectivity. A description of the ground stations is also included.

  13. Advanced Electrical, Optical and Data Communication Infrastructure Development

    SciTech Connect

    Simon Cobb

    2011-04-30

    The implementation of electrical and IT infrastructure systems at the North Carolina Center for Automotive Research , Inc. (NCCAR) has achieved several key objectives in terms of system functionality, operational safety and potential for ongoing research and development. Key conclusions include: (1) The proven ability to operate a high speed wireless data network over a large 155 acre area; (2) Node to node wireless transfers from access points are possible at speeds of more than 50 mph while maintaining high volume bandwidth; (3) Triangulation of electronic devices/users is possible in areas with overlapping multiple access points, outdoor areas with reduced overlap of access point coverage considerably reduces triangulation accuracy; (4) Wireless networks can be adversely affected by tree foliage, pine needles are a particular challenge due to the needle length relative to the transmission frequency/wavelength; and (5) Future research will use the project video surveillance and wireless systems to further develop automated image tracking functionality for the benefit of advanced vehicle safety monitoring and autonomous vehicle control through 'vehicle-to-vehicle' and 'vehicle-to-infrastructure' communications. A specific advantage realized from this IT implementation at NCCAR is that NC State University is implementing a similar wireless network across Centennial Campus, Raleigh, NC in 2011 and has benefited from lessons learned during this project. Consequently, students, researchers and members of the public will be able to benefit from a large scale IT implementation with features and improvements derived from this NCCAR project.

  14. Advanced mobile satellite communications using COMETS satellite in MM-wave and Ka-band

    NASA Technical Reports Server (NTRS)

    Ohmori, Shingo; Isobe, Shunkichi; Takeuchi, Makoto; Naito, Hideyuki

    1993-01-01

    Early in the 21st century, the demand for personal communications using mobile, hand-held, and VSAT terminals will rapidly increase. In a future system, many different types of services should be provided with one-hop connection. The Communications Research Laboratory (CRL) has studied a future advanced mobile satellite communications system using millimeter wave and Ka band. In 1990, CRL started the Communications and Broadcasting Engineering Test Satellite (COMETS) project. The satellite has been developed in conjunction with NASDA and will be launched in 1997. This paper describes the COMETS payload configuration and the experimental system for the advanced mobile communications mission.

  15. Public classical communication in quantum cryptography: Error correction, integrity, and authentication

    SciTech Connect

    Timofeev, A. V.; Pomozov, D. I.; Makkaveev, A. P.; Molotkov, S. N.

    2007-05-15

    Quantum cryptography systems combine two communication channels: a quantum and a classical one. (They can be physically implemented in the same fiber-optic link, which is employed as a quantum channel when one-photon states are transmitted and as a classical one when it carries classical data traffic.) Both channels are supposed to be insecure and accessible to an eavesdropper. Error correction in raw keys, interferometer balancing, and other procedures are performed by using the public classical channel. A discussion of the requirements to be met by the classical channel is presented.

  16. Lossless quantum prefix compression for communication channels that are always open

    NASA Astrophysics Data System (ADS)

    Müller, Markus; Rogers, Caroline; Nagarajan, Rajagopal

    2009-01-01

    We describe a method for lossless quantum compression if the output of the information source is not known. We compute the best possible compression rate, minimizing the expected base length of the output quantum bit string (the base length of a quantum string is the maximal length in the superposition). This complements work by Schumacher and Westmoreland who calculated the corresponding rate for minimizing the output’s average length. Our compressed code words are prefix-free indeterminate-length quantum bit strings which can be concatenated in the case of multiple sources. Therefore, we generalize the known theory of prefix-free quantum codes to the case where strings have indeterminate length. Moreover, we describe a communication model which allows the lossless transmission of the compressed code words. The benefit of compression is then the reduction of transmission errors in the presence of noise.

  17. A probabilistic quantum communication protocol using mixed entangled channel

    NASA Astrophysics Data System (ADS)

    Choudhury, Binayak S.; Dhara, Arpan

    2016-05-01

    Qubits are realized as polarization state of photons or as superpositions of the spin states of electrons. In this paper we propose a scheme to probabilistically teleport an unknown arbitrary two-qubit state using a non-maximally entangled GHZ- like state and a non-maximally Bell state simultaneously as quantum channels. We also discuss the success probability of our scheme. We perform POVM in the protocol which is operationally advantageous. In our scheme we show that the non-maximal quantum resources perform better than maximal resources.

  18. Quantum entanglement and the communication complexity of the inner product function

    SciTech Connect

    Cleve, R.; Dam, W. van |; Nielsen, M. |; Tapp, A.

    1998-08-01

    The authors consider the communication complexity of the binary inner product function in a variation of the two-party scenario where the parties have an a priori supply of particles in an entangled quantum state. They prove linear lower bounds for both exact protocols, as well as for protocols that determine the answer with bounded-error probability. The proofs employ a novel kind of quantum reduction from multibit communication problems to the problem of computing the inner product. The communication required for the former problem can then be bounded by an application of Holevo`s theorem. They also give a specific example of a probabilistic scenario where entanglement reduces the communication complexity of the inner product function by one bit.

  19. Experimental error filtration for quantum communication over highly noisy channels.

    PubMed

    Lamoureux, L-P; Brainis, E; Cerf, N J; Emplit, Ph; Haelterman, M; Massar, S

    2005-06-17

    Error filtration is a method for encoding the quantum state of a single particle into a higher dimensional Hilbert space in such a way that it becomes less sensitive to noise. We have realized a fiber optics demonstration of this method and illustrated its potentialities by carrying out the optical part of a quantum key distribution scheme over a line whose phase noise is too high for a standard implementation of BB84 to be secure. By filtering out the noise, a bit error rate of 15.3% +/- 0.1%, which is beyond the security limit, can be reduced to 10.6% +/- 0.1%, thereby guaranteeing the cryptographic security. PMID:16090449

  20. On the passive probing of fiber optic quantum communication channels

    SciTech Connect

    Korol'kov, A. V.; Katamadze, K. G.; Kulik, S. P.; Molotkov, S. N.

    2010-04-15

    Avalanche photodetectors based on InGaAs:P are the most sensitive and only detectors operating in the telecommunication wavelength range 1.30-1.55 {mu}m in the fiber optic quantum cryptography systems that can operate in the single photon count mode. In contrast to the widely used silicon photodetectors for wavelengths up to 1 {mu}m operating in a waiting mode, these detectors always operate in a gated mode. The production of an electron-hole pair in the process of the absorption of a photon and the subsequent appearance of an avalanche of carriers can be accompanied by the inverse processes of the recombination and emission of photons. Such a backward emission can present a potential serious problem for the stability of fiber optic quantum cryptography systems against passive probing. The results of analyzing the detection of backscattered radiation are reported. The probability of such an emission has been estimated.

  1. Number-theoretic nature of communication in quantum spin systems.

    PubMed

    Godsil, Chris; Kirkland, Stephen; Severini, Simone; Smith, Jamie

    2012-08-01

    The last decade has witnessed substantial interest in protocols for transferring information on networks of quantum mechanical objects. A variety of control methods and network topologies have been proposed, on the basis that transfer with perfect fidelity-i.e., deterministic and without information loss-is impossible through unmodulated spin chains with more than a few particles. Solving the original problem formulated by Bose [Phys. Rev. Lett. 91, 207901 (2003)], we determine the exact number of qubits in unmodulated chains (with an XY Hamiltonian) that permit transfer with a fidelity arbitrarily close to 1, a phenomenon called pretty good state transfer. We prove that this happens if and only if the number of nodes is n = p - 1, 2p - 1, where p is a prime, or n = 2(m) - 1. The result highlights the potential of quantum spin system dynamics for reinterpreting questions about the arithmetic structure of integers and, in this case, primality. PMID:23006153

  2. A generalized architecture of quantum secure direct communication for N disjointed users with authentication.

    PubMed

    Farouk, Ahmed; Zakaria, Magdy; Megahed, Adel; Omara, Fatma A

    2015-01-01

    In this paper, we generalize a secured direct communication process between N users with partial and full cooperation of quantum server. So, N - 1 disjointed users u1, u2, …, uN-1 can transmit a secret message of classical bits to a remote user uN by utilizing the property of dense coding and Pauli unitary transformations. The authentication process between the quantum server and the users are validated by EPR entangled pair and CNOT gate. Afterwards, the remained EPR will generate shared GHZ states which are used for directly transmitting the secret message. The partial cooperation process indicates that N - 1 users can transmit a secret message directly to a remote user uN through a quantum channel. Furthermore, N - 1 users and a remote user uN can communicate without an established quantum channel among them by a full cooperation process. The security analysis of authentication and communication processes against many types of attacks proved that the attacker cannot gain any information during intercepting either authentication or communication processes. Hence, the security of transmitted message among N users is ensured as the attacker introduces an error probability irrespective of the sequence of measurement.

  3. A generalized architecture of quantum secure direct communication for N disjointed users with authentication

    PubMed Central

    Farouk, Ahmed; Zakaria, Magdy; Megahed, Adel; Omara, Fatma A.

    2015-01-01

    In this paper, we generalize a secured direct communication process between N users with partial and full cooperation of quantum server. So, N − 1 disjointed users u1, u2, …, uN−1 can transmit a secret message of classical bits to a remote user uN by utilizing the property of dense coding and Pauli unitary transformations. The authentication process between the quantum server and the users are validated by EPR entangled pair and CNOT gate. Afterwards, the remained EPR will generate shared GHZ states which are used for directly transmitting the secret message. The partial cooperation process indicates that N − 1 users can transmit a secret message directly to a remote user uN through a quantum channel. Furthermore, N − 1 users and a remote user uN can communicate without an established quantum channel among them by a full cooperation process. The security analysis of authentication and communication processes against many types of attacks proved that the attacker cannot gain any information during intercepting either authentication or communication processes. Hence, the security of transmitted message among N users is ensured as the attacker introduces an error probability irrespective of the sequence of measurement. PMID:26577473

  4. Man-in-the-middle attack on quantum secure communications with authentication

    NASA Astrophysics Data System (ADS)

    Lin, Tzu Han; Hwang, Tzonelish

    2014-04-01

    This study points out a man-in-the-middle (MIM) attack on many of quantum secure communication with authentication protocols. The MIM attack is due to a design carelessness on performing public discussions on a nonauthenticated classical channel. A possible solution is proposed to solve the problem.

  5. A generalized architecture of quantum secure direct communication for N disjointed users with authentication

    NASA Astrophysics Data System (ADS)

    Farouk, Ahmed; Zakaria, Magdy; Megahed, Adel; Omara, Fatma A.

    2015-11-01

    In this paper, we generalize a secured direct communication process between N users with partial and full cooperation of quantum server. So, N - 1 disjointed users u1, u2, …, uN-1 can transmit a secret message of classical bits to a remote user uN by utilizing the property of dense coding and Pauli unitary transformations. The authentication process between the quantum server and the users are validated by EPR entangled pair and CNOT gate. Afterwards, the remained EPR will generate shared GHZ states which are used for directly transmitting the secret message. The partial cooperation process indicates that N - 1 users can transmit a secret message directly to a remote user uN through a quantum channel. Furthermore, N - 1 users and a remote user uN can communicate without an established quantum channel among them by a full cooperation process. The security analysis of authentication and communication processes against many types of attacks proved that the attacker cannot gain any information during intercepting either authentication or communication processes. Hence, the security of transmitted message among N users is ensured as the attacker introduces an error probability irrespective of the sequence of measurement.

  6. Necessary and sufficient optimality conditions for classical simulations of quantum communication processes

    NASA Astrophysics Data System (ADS)

    Montina, Alberto; Wolf, Stefan

    2014-07-01

    We consider the process consisting of preparation, transmission through a quantum channel, and subsequent measurement of quantum states. The communication complexity of the channel is the minimal amount of classical communication required for classically simulating it. Recently, we reduced the computation of this quantity to a convex minimization problem with linear constraints. Every solution of the constraints provides an upper bound on the communication complexity. In this paper, we derive the dual maximization problem of the original one. The feasible points of the dual constraints, which are inequalities, give lower bounds on the communication complexity, as illustrated with an example. The optimal values of the two problems turn out to be equal (zero duality gap). By this property, we provide necessary and sufficient conditions for optimality in terms of a set of equalities and inequalities. We use these conditions and two reasonable but unproven hypotheses to derive the lower bound n ×2n -1 for a noiseless quantum channel with capacity equal to n qubits. This lower bound can have interesting consequences in the context of the recent debate on the reality of the quantum state.

  7. Multiplexing OAM states in an optical fiber: Increase bandwidth of quantum communication and QKD applications

    NASA Astrophysics Data System (ADS)

    Gupta, Manish Kumar; Dowling, Jonathan P.

    2015-05-01

    We propose a noble method for multiplexing OAM states to increase bandwidth of communication in a birefringent single-mode optical fiber for quantum communication and QKD applications by minimizing the decoherence. We analytically derive and show that the rate of decoherence for OAM state in a birefringent optical fiber is proportional to l2. We also show numerically that decoherence can be minimized with CPMG pulse sequence to preserve the state with > 90 % fidelity for smaller values of l to allow for high-bandwidth communication. Louisiana State University, Baton Rouge, Louisiana 70803, USA.

  8. Entanglement distillation for quantum communication network with atomic-ensemble memories.

    PubMed

    Li, Tao; Yang, Guo-Jian; Deng, Fu-Guo

    2014-10-01

    Atomic ensembles are effective memory nodes for quantum communication network due to the long coherence time and the collective enhancement effect for the nonlinear interaction between an ensemble and a photon. Here we investigate the possibility of achieving the entanglement distillation for nonlocal atomic ensembles by the input-output process of a single photon as a result of cavity quantum electrodynamics. We give an optimal entanglement concentration protocol (ECP) for two-atomic-ensemble systems in a partially entangled pure state with known parameters and an efficient ECP for the systems in an unknown partially entangled pure state with a nondestructive parity-check detector (PCD). For the systems in a mixed entangled state, we introduce an entanglement purification protocol with PCDs. These entanglement distillation protocols have high fidelity and efficiency with current experimental techniques, and they are useful for quantum communication network with atomic-ensemble memories.

  9. FAST TRACK COMMUNICATION: A stable toolkit method in quantum control

    NASA Astrophysics Data System (ADS)

    Belhadj, M.; Salomon, J.; Turinici, G.

    2008-09-01

    Recently the 'toolkit' discretization introduced to accelerate the numerical resolution of the time-dependent Schrödinger equation arising in quantum optimal control problems demonstrated good results on a large range of models. However, when coupling this class of methods with the so-called monotonically convergent algorithms, numerical instabilities affect the convergence of the discretized scheme. We present an adaptation of the 'toolkit' method which preserves the monotonicity of the procedure. The theoretical properties of the new algorithm are illustrated by numerical simulations.

  10. Non-Markovian effects on quantum-communication protocols

    SciTech Connect

    Yeo, Ye; Oh, C. H.; An, Jun-Hong

    2010-09-15

    We show how, under the influence of non-Markovian environments, two different maximally entangled Bell states give rise to states that have equal classical correlations and the same capacities to violate the Bell-Clauser-Horne-Shimony-Holt inequality, but intriguingly differing usefulness for teleportation and dense coding. We elucidate how different entanglement measures like negativity and concurrence, and two different measures of quantum discord, could account for these behaviors. In particular, we explicitly show how the Ollivier-Zurek measure of discord directly accounts for one state being a better resource for dense coding compared to another. Our study leads to several important issues about these measures of discord.

  11. Plan of advanced satellite communication experiments using ETS-6

    NASA Technical Reports Server (NTRS)

    Ikegami, Tetsushi

    1989-01-01

    In 1992, an Engineering Test Satellite 6 is scheduled to be launched by an H-2 rocket. The missions of ETS-6 are to establish basic technologies of inter-satellite communications using S-band, millimeter waves and optical beams and of fixed and mobile satellite communications using multibeam antenna on board the satellite. A plan of the experiments is introduced.

  12. Advanced communication infrastructure for pre-hospital EMS care.

    PubMed

    Orthner, Helmuth; Mazza, Giovanni; Mazza, Giovanni Giorgio; Shenvi, Rohit; Battles, Marcie

    2008-11-06

    The traditional communication infrastructure of the pre-hospital Emergency Medical System (EMS) is limited to voice communication using radio or cell phone technologies. With the emergence of 3rd Generation wireless networks (3G) and enhanced mobile devices capable of data communication (e.g., mobile tablets, PDAs with cell phones, or cell phones with PDA capabilities), the voice communication can be enhanced with interactive data messaging and perhaps even with interactive video communication. However, video requires substantially more bandwidth which 4th Generation (4G) systems are promising. However, their availability is limited. We present an infrastructure that allows dynamic selection of the best data transport mode in the pre-hospital EMS environment.

  13. Secure communications with low-orbit spacecraft using quantum cryptography

    DOEpatents

    Hughes, Richard J.; Buttler, William T.; Kwiat, Paul G.; Luther, Gabriel G.; Morgan, George L; Nordholt, Jane E.; Peterson, Charles G.; Simmons, Charles M.

    1999-01-01

    Apparatus and method for secure communication between an earth station and spacecraft. A laser outputs single pulses that are split into preceding bright pulses and delayed attenuated pulses, and polarized. A Pockels cell changes the polarization of the polarized delayed attenuated pulses according to a string of random numbers, a first polarization representing a "1," and a second polarization representing a "0." At the receiving station, a beamsplitter randomly directs the preceding bright pulses and the polarized delayed attenuated pulses onto longer and shorter paths, both terminating in a beamsplitter which directs the preceding bright pulses and a first portion of the polarized delayed attenuated pulses to a first detector, and a second portion of the polarized delayed attenuated pulses to a second detector to generate a key for secure communication between the earth station and the spacecraft.

  14. Detecting relay attacks on RFID communication systems using quantum bits

    NASA Astrophysics Data System (ADS)

    Jannati, Hoda; Ardeshir-Larijani, Ebrahim

    2016-08-01

    RFID systems became widespread in variety of applications because of their simplicity in manufacturing and usability. In the province of critical infrastructure protection, RFID systems are usually employed to identify and track people, objects and vehicles that enter restricted areas. The most important vulnerability which is prevalent among all protocols employed in RFID systems is against relay attacks. Until now, to protect RFID systems against this kind of attack, the only approach is the utilization of distance-bounding protocols which are not applicable over low-cost devices such as RFID passive tags. This work presents a novel technique using emerging quantum technologies to detect relay attacks on RFID systems. Recently, it is demonstrated that quantum key distribution (QKD) can be implemented in a client-server scheme where client only requires an on-chip polarization rotator that may be integrated into a handheld device. Now we present our technique for a tag-reader scenario which needs similar resources as the mentioned QKD scheme. We argue that our technique requires less resources and provides lower probability of false alarm for the system, compared with distance-bounding protocols, and may pave the way to enhance the security of current RFID systems.

  15. A Compact Readout Electronics for the Ground Station of a Quantum Communication Satellite

    NASA Astrophysics Data System (ADS)

    Qi, Binxiang; Liu, Shubin; Shen, Qi; Liao, Shengkai; Cai, Wenqi; Lin, Zehong; Liu, Weiyue; Peng, Chengzhi; An, Qi

    2015-06-01

    Since the 1990s, there has been a dramatic interest in quantum communication. Free-space quantum communication is being developed to ultra-long distance quantum experiment, which requires higher electronics performance, such as time measurement precision, data-transfer rate, and system integration density. As part of the ground station of quantum experiment satellite that will be launched in 2016, we specifically designed a compact PCI-based multi-channel electronics system with high time-resolution, high data-transfer-rate. The electronics performance of this system was tested. The time bin size is 23.9ps and the time precision root-mean-square (RMS) is less than 24ps for 16 channels. The dead time is 30ns. The data transfer rate to local computer is up to 35 MBps, and the count rate is up to 30M/s. The system has been proven to perform well and operate stably through a test of free space quantum key distribution (QKD) experiment.

  16. Deterministic Secure Quantum Communication and Authentication Protocol based on Extended GHZ-W State and Quantum One-time Pad

    NASA Astrophysics Data System (ADS)

    Li, Na; Li, Jian; Li, Lei-Lei; Wang, Zheng; Wang, Tao

    2016-08-01

    A deterministic secure quantum communication and authentication protocol based on extended GHZ-W state and quantum one-time pad is proposed. In the protocol, state | φ -> is used as the carrier. One photon of | φ -> state is sent to Alice, and Alice obtains a random key by measuring photons with bases determined by ID. The information of bases is secret to others except Alice and Bob. Extended GHZ-W states are used as decoy photons, the positions of which in information sequence are encoded with identity string ID of the legal user, and the eavesdropping detection rate reaches 81%. The eavesdropping detection based on extended GHZ-W state combines with authentication and the secret ID ensures the security of the protocol.

  17. Advanced information processing system: Authentication protocols for network communication

    NASA Technical Reports Server (NTRS)

    Harper, Richard E.; Adams, Stuart J.; Babikyan, Carol A.; Butler, Bryan P.; Clark, Anne L.; Lala, Jaynarayan H.

    1994-01-01

    In safety critical I/O and intercomputer communication networks, reliable message transmission is an important concern. Difficulties of communication and fault identification in networks arise primarily because the sender of a transmission cannot be identified with certainty, an intermediate node can corrupt a message without certainty of detection, and a babbling node cannot be identified and silenced without lengthy diagnosis and reconfiguration . Authentication protocols use digital signature techniques to verify the authenticity of messages with high probability. Such protocols appear to provide an efficient solution to many of these problems. The objective of this program is to develop, demonstrate, and evaluate intercomputer communication architectures which employ authentication. As a context for the evaluation, the authentication protocol-based communication concept was demonstrated under this program by hosting a real-time flight critical guidance, navigation and control algorithm on a distributed, heterogeneous, mixed redundancy system of workstations and embedded fault-tolerant computers.

  18. A Simultaneous Quantum Secure Direct Communication Scheme between the Central Party and Other M Parties

    NASA Astrophysics Data System (ADS)

    Gao, Ting; Yan, Feng-Li; Wang, Zhi-Xi

    2005-10-01

    We propose a simultaneous quantum secure direct communication scheme between one party and other three parties via four-particle GHZ states and swapping quantum entanglement. In the scheme, three spatially separated senders, Alice, Bob and Charlie, transmit their secret messages to a remote receiver Diana by performing a series of local operations on their respective particles according to the quadripartite stipulation. From Alice, Bob, Charlie and Diana's Bell measurement results, Diana can infer the secret messages. If a perfect quantum channel is used, the secret messages are faithfully transmitted from Alice, Bob and Charlie to Diana via initially shared pairs of four-particle GHZ states without revealing any information to a potential eavesdropper. As there is no transmission of the qubits carrying the secret message in the public channel, it is completely secure for the direct secret communication. This scheme can be considered as a network of communication parties where each party wants to communicate secretly with a central party or server.

  19. Time-reversal-symmetric single-photon wave packets for free-space quantum communication.

    PubMed

    Trautmann, N; Alber, G; Agarwal, G S; Leuchs, G

    2015-05-01

    Readout and retrieval processes are proposed for efficient, high-fidelity quantum state transfer between a matter qubit, encoded in the level structure of a single atom or ion, and a photonic qubit, encoded in a time-reversal-symmetric single-photon wave packet. They are based on controlling spontaneous photon emission and absorption of a matter qubit on demand in free space by stimulated Raman adiabatic passage. As these processes do not involve mode selection by high-finesse cavities or photon transport through optical fibers, they offer interesting perspectives as basic building blocks for free-space quantum-communication protocols.

  20. Strong Converse Exponents for a Quantum Channel Discrimination Problem and Quantum-Feedback-Assisted Communication

    NASA Astrophysics Data System (ADS)

    Cooney, Tom; Mosonyi, Milán; Wilde, Mark M.

    2016-06-01

    This paper studies the difficulty of discriminating between an arbitrary quantum channel and a "replacer" channel that discards its input and replaces it with a fixed state. The results obtained here generalize those known in the theory of quantum hypothesis testing for binary state discrimination. We show that, in this particular setting, the most general adaptive discrimination strategies provide no asymptotic advantage over non-adaptive tensor-power strategies. This conclusion follows by proving a quantum Stein's lemma for this channel discrimination setting, showing that a constant bound on the Type I error leads to the Type II error decreasing to zero exponentially quickly at a rate determined by the maximum relative entropy registered between the channels. The strong converse part of the lemma states that any attempt to make the Type II error decay to zero at a rate faster than the channel relative entropy implies that the Type I error necessarily converges to one. We then refine this latter result by identifying the optimal strong converse exponent for this task. As a consequence of these results, we can establish a strong converse theorem for the quantum-feedback-assisted capacity of a channel, sharpening a result due to Bowen. Furthermore, our channel discrimination result demonstrates the asymptotic optimality of a non-adaptive tensor-power strategy in the setting of quantum illumination, as was used in prior work on the topic. The sandwiched Rényi relative entropy is a key tool in our analysis. Finally, by combining our results with recent results of Hayashi and Tomamichel, we find a novel operational interpretation of the mutual information of a quantum channel {mathcal{N}} as the optimal Type II error exponent when discriminating between a large number of independent instances of {mathcal{N}} and an arbitrary "worst-case" replacer channel chosen from the set of all replacer channels.

  1. Advanced communications technology satellite high burst rate link evaluation terminal communication protocol software user's guide, version 1.0

    NASA Technical Reports Server (NTRS)

    Reinhart, Richard C.

    1993-01-01

    The Communication Protocol Software was developed at the NASA Lewis Research Center to support the Advanced Communications Technology Satellite High Burst Rate Link Evaluation Terminal (ACTS HBR-LET). The HBR-LET is an experimenters terminal to communicate with the ACTS for various experiments by government, university, and industry agencies. The Communication Protocol Software is one segment of the Control and Performance Monitor (C&PM) Software system of the HBR-LET. The Communication Protocol Software allows users to control and configure the Intermediate Frequency Switch Matrix (IFSM) on board the ACTS to yield a desired path through the spacecraft payload. Besides IFSM control, the C&PM Software System is also responsible for instrument control during HBR-LET experiments, uplink power control of the HBR-LET to demonstrate power augmentation during signal fade events, and data display. The Communication Protocol Software User's Guide, Version 1.0 (NASA CR-189162) outlines the commands and procedures to install and operate the Communication Protocol Software. Configuration files used to control the IFSM, operator commands, and error recovery procedures are discussed. The Communication Protocol Software Maintenance Manual, Version 1.0 (NASA CR-189163, to be published) is a programmer's guide to the Communication Protocol Software. This manual details the current implementation of the software from a technical perspective. Included is an overview of the Communication Protocol Software, computer algorithms, format representations, and computer hardware configuration. The Communication Protocol Software Test Plan (NASA CR-189164, to be published) provides a step-by-step procedure to verify the operation of the software. Included in the Test Plan is command transmission, telemetry reception, error detection, and error recovery procedures.

  2. Efficient Multi-Dimensional Simulation of Quantum Confinement Effects in Advanced MOS Devices

    NASA Technical Reports Server (NTRS)

    Biegel, Bryan A.; Ancona, Mario G.; Rafferty, Conor S.; Yu, Zhiping

    2000-01-01

    We investigate the density-gradient (DG) transport model for efficient multi-dimensional simulation of quantum confinement effects in advanced MOS devices. The formulation of the DG model is described as a quantum correction ot the classical drift-diffusion model. Quantum confinement effects are shown to be significant in sub-100nm MOSFETs. In thin-oxide MOS capacitors, quantum effects may reduce gate capacitance by 25% or more. As a result, the inclusion of quantum effects may reduce gate capacitance by 25% or more. As a result, the inclusion of quantum effects in simulations dramatically improves the match between C-V simulations and measurements for oxide thickness down to 2 nm. Significant quantum corrections also occur in the I-V characteristics of short-channel (30 to 100 nm) n-MOSFETs, with current drive reduced by up to 70%. This effect is shown to result from reduced inversion charge due to quantum confinement of electrons in the channel. Also, subthreshold slope is degraded by 15 to 20 mV/decade with the inclusion of quantum effects via the density-gradient model, and short channel effects (in particular, drain-induced barrier lowering) are noticeably increased.

  3. Advanced Level Physics Students' Conceptions of Quantum Physics.

    ERIC Educational Resources Information Center

    Mashhadi, Azam

    This study addresses questions about particle physics that focus on the nature of electrons. Speculations as to whether they are more like particles or waves or like neither illustrate the difficulties with which students are confronted when trying to incorporate the concepts of quantum physics into their overall conceptual framework. Such…

  4. Novel Multiparty Controlled Bidirectional Quantum Secure Direct Communication Based on Continuous-variable States

    NASA Astrophysics Data System (ADS)

    Yu, Zhen-Bo; Gong, Li-Hua; Wen, Ru-Hong

    2016-03-01

    A novel multiparty controlled bidirectional quantum secure direct communication protocol combining continuous-variable states with qubit block transmission is proposed. Two legitimate communication parties encode their own secret information into entangled optical modes with translation operations, and the secret information of each counterpart can only be recovered under the permission of all controllers. Due to continuous-variable states and block transmission strategy, the proposed protocol is easy to realize with perfect qubit efficiency. Security analyses show that the proposed protocol is free from common attacks, including the man-in-the-middle attack.

  5. Controlled quantum secure direct communication by entanglement distillation or generalized measurement

    NASA Astrophysics Data System (ADS)

    Tan, Xiaoqing; Zhang, Xiaoqian

    2016-05-01

    We propose two controlled quantum secure communication schemes by entanglement distillation or generalized measurement. The sender Alice, the receiver Bob and the controllers David and Cliff take part in the whole schemes. The supervisors David and Cliff can control the information transmitted from Alice to Bob by adjusting the local measurement angles θ _4 and θ _3. Bob can verify his secret information by classical one-way function after communication. The average amount of information is analyzed and compared for these two methods by MATLAB. The generalized measurement is a better scheme. Our schemes are secure against some well-known attacks because classical encryption and decoy states are used to ensure the security of the classical channel and the quantum channel.

  6. Identifying Successful Advancement Approaches in Four Catholic Universities: The Effectiveness of the Four Advancement Models of Communication

    ERIC Educational Resources Information Center

    Bonglia, Jean-Pierre K.

    2010-01-01

    The current longitudinal study of the most successful Catholic universities in the United States identifies the prevalence of four advancement models of communication that have contributed to make those institutions successful in their philanthropic efforts. While research by Grunig and Kelly maintained that the two-way symmetrical model of…

  7. Quantum direct communication protocol strengthening against Pavičić’s attack

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Shi, Wei-Xu; Wang, Jian; Tang, Chao-Jing

    2015-12-01

    A quantum circuit providing an undetectable eavesdropping of information in message mode, which compromises all two-state ψ-ϕ quantum direct communication (QDC) protocols, has been recently proposed by Pavičić [Phys. Rev. A 87 (2013) 042326]. A modification of the protocol’s control mode is proposed, which improves users’ 25% detection probability of Eve to 50% at best, as that in ping-pong protocol. The modification also improves the detection probability of Wójcik’s attack [Phys. Rev. Lett 90 (2003) 157901] to 75% at best. The resistance against man-in-the-middle (MITM) attack as well as the discussion of security for four Bell state protocols is presented. As a result, the protocol security is strengthened both theoretically and practically, and quantum advantage of superdense coding is restored.

  8. Communication: Excited states, dynamic correlation functions and spectral properties from full configuration interaction quantum Monte Carlo.

    PubMed

    Booth, George H; Chan, Garnet Kin-Lic

    2012-11-21

    In this communication, we propose a method for obtaining isolated excited states within the full configuration interaction quantum Monte Carlo framework. This method allows for stable sampling with respect to collapse to lower energy states and requires no uncontrolled approximations. In contrast with most previous methods to extract excited state information from quantum Monte Carlo methods, this results from a modification to the underlying propagator, and does not require explicit orthogonalization, analytic continuation, transient estimators, or restriction of the Hilbert space via a trial wavefunction. Furthermore, we show that the propagator can directly yield frequency-domain correlation functions and spectral functions such as the density of states which are difficult to obtain within a traditional quantum Monte Carlo framework. We demonstrate this approach with pilot applications to the neon atom and beryllium dimer.

  9. Space-to-ground quantum communication using an optical ground station: a feasibility study

    NASA Astrophysics Data System (ADS)

    Villoresi, Paolo; Tamburini, Fabrizio; Aspelmeyer, Markus; Jennewein, Thomas; Ursin, Rupert; Pernechele, Claudio; Bianco, Giuseppe; Zeilinger, Anton; Barbieri, Cesare

    2004-10-01

    We have tested the experimental prerequisites for a Space-to-Ground quantum communication link between satellites and an optical ground station. The feasibility of our ideas is being tested using the facilities of the ASI Matera Laser Ranging Observatory (MLRO) and existing geodetic satellites such as Lageos 1 and 2. Specific emphasis is put on the necessary technological modifications of the existing infrastructure to achieve single photon reception from an orbiting satellite.

  10. Comment on "Quantum Secure Direct Communication with Authentication Expansion Using Single Photons"

    NASA Astrophysics Data System (ADS)

    Yang, Yu-Guang; Jia, Xin; Xia, Juan; Shi, Lei; Zhang, Hua

    2012-12-01

    The security of the quantum secure direct communication protocol with authentication expansion using single photons is analyzed. It is shown that an eavesdropper can obtain or even modify the transmitted secret without introducing any error by implementing a simple man-in-the-middle attack after the authentication is successfully carried out. Furthermore, a denial-of-service attack is also discussed. The particular attack strategy is demonstrated and an improved protocol is presented.

  11. Cryptanalysis of Quantum Secure Direct Communication and Authentication Scheme via Bell States

    NASA Astrophysics Data System (ADS)

    Gao, Fei; Qin, Su-Juan; Guo, Fen-Zhuo; Wen, Qiao-Yan

    2011-02-01

    The security of the quantum secure direct communication (QSDC) and authentication protocol based on Bell states is analyzed. It is shown that an eavesdropper can invalidate the authentication function, and implement a successful man-in-the-middle attack, where he/she can obtain or even modify the transmitted secret without introducing any error. The particular attack strategy is demonstrated and an improved protocol is presented.

  12. Classroom Communication and Instructional Processes: Advances through Meta-Analysis

    ERIC Educational Resources Information Center

    Gayle, Barbara Mae, Ed.; Preiss, Raymond W., Ed.; Burrell, Nancy, Ed.; Allen, Mike, Ed.

    2006-01-01

    This volume offers a systematic review of the literature on communication education and instruction. Making meta-analysis findings accessible and relevant, the editors of this volume approach the topic from the perspective that meta-analysis serves as a useful tool for summarizing experiments and for determining how and why specific teaching and…

  13. Quantum Limits of Space-to-Ground Optical Communications

    NASA Technical Reports Server (NTRS)

    Hemmati, H.; Dolinar, S.

    2012-01-01

    For a pure loss channel, the ultimate capacity can be achieved with classical coherent states (i.e., ideal laser light): (1) Capacity-achieving receiver (measurement) is yet to be determined. (2) Heterodyne detection approaches the ultimate capacity at high mean photon numbers. (3) Photon-counting approaches the ultimate capacity at low mean photon numbers. A number of current technology limits drive the achievable performance of free-space communication links. Approaching fundamental limits in the bandwidth-limited regime: (1) Heterodyne detection with high-order coherent-state modulation approaches ultimate limits. SOA improvements to laser phase noise, adaptive optics systems for atmospheric transmission would help. (2) High-order intensity modulation and photon-counting can approach heterodyne detection within approximately a factor of 2. This may have advantages over coherent detection in the presence of turbulence. Approaching fundamental limits in the photon-limited regime (1) Low-duty cycle binary coherent-state modulation (OOK, PPM) approaches ultimate limits. SOA improvements to laser extinction ratio, receiver dark noise, jitter, and blocking would help. (2) In some link geometries (near field links) number-state transmission could improve over coherent-state transmission

  14. Quantum Well and Quantum Dot Modeling for Advanced Infrared Detectors and Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Ting, David; Gunapala, S. D.; Bandara, S. V.; Hill, C. J.

    2006-01-01

    This viewgraph presentation reviews the modeling of Quantum Well Infrared Detectors (QWIP) and Quantum Dot Infrared Detectors (QDIP) in the development of Focal Plane Arrays (FPA). The QWIP Detector being developed is a dual band detector. It is capable of running on two bands Long-Wave Infrared (LWIR) and Medium Wavelength Infrared (MWIR). The same large-format dual-band FPA technology can be applied to Quantum Dot Infrared Photodetector (QDIP) with no modification, once QDIP exceeds QWIP in single device performance. Details of the devices are reviewed.

  15. Efficient Multi-Dimensional Simulation of Quantum Confinement Effects in Advanced MOS Devices

    NASA Technical Reports Server (NTRS)

    Biegel, Bryan A.; Rafferty, Conor S.; Ancona, Mario G.; Yu, Zhi-Ping

    2000-01-01

    We investigate the density-gradient (DG) transport model for efficient multi-dimensional simulation of quantum confinement effects in advanced MOS devices. The formulation of the DG model is described as a quantum correction to the classical drift-diffusion model. Quantum confinement effects are shown to be significant in sub-100nm MOSFETs. In thin-oxide MOS capacitors, quantum effects may reduce gate capacitance by 25% or more. As a result, the inclusion or quantum effects in simulations dramatically improves the match between C-V simulations and measurements for oxide thickness down to 2 nm. Significant quantum corrections also occur in the I-V characteristics of short-channel (30 to 100 nm) n-MOSFETs, with current drive reduced by up to 70%. This effect is shown to result from reduced inversion charge due to quantum confinement of electrons in the channel. Also, subthreshold slope is degraded by 15 to 20 mV/decade with the inclusion of quantum effects via the density-gradient model, and short channel effects (in particular, drain-induced barrier lowering) are noticeably increased.

  16. LTE-advanced random access mechanism for M2M communication: A review

    NASA Astrophysics Data System (ADS)

    Mustafa, Rashid; Sarowa, Sandeep; Jaglan, Reena Rathee; Khan, Mohammad Junaid; Agrawal, Sunil

    2016-03-01

    Machine Type Communications (MTC) enables one or more self-sufficient machines to communicate directly with one another without human interference. MTC applications include smart grid, security, e-Health and intelligent automation system. To support huge numbers of MTC devices, one of the challenging issues is to provide a competent way for numerous access in the network and to minimize network overload. In this article, the different control mechanisms for overload random access are reviewed to avoid congestion caused by random access channel (RACH) of MTC devices. However, past and present wireless technologies have been engineered for Human-to-Human (H2H) communications, in particular, for transmission of voice. Consequently the Long Term Evolution (LTE) -Advanced is expected to play a central role in communicating Machine to Machine (M2M) and are very optimistic about H2H communications. Distinct and unique characteristics of M2M communications create new challenges from those in H2H communications. In this article, we investigate the impact of massive M2M terminals attempting random access to LTE-Advanced all at once. We discuss and review the solutions to alleviate the overload problem by Third Generation Partnership Project (3GPP). As a result, we evaluate and compare these solutions that can effectively eliminate the congestion on the random access channel for M2M communications without affecting H2H communications.

  17. Communication, Interventions, and Scientific Advances in Autism: A Commentary

    PubMed Central

    Llaneza, Danielle C.; DeLuke, Susan V.; Batista, Myra; Crawley, Jacqueline N.; Christodulu, Kristin V.; Frye, Cheryl A.

    2010-01-01

    Autism spectrum disorders (ASD) affect approximately 1 in 150 children across the U.S., and are characterized by abnormal social actions, language difficulties, repetitive or restrictive behaviors, and special interests. ASD include autism (autistic disorder), Asperger syndrome, and Pervasive Developmental Disorder not otherwise specified (PDD-NOS or atypical autism). High-functioning individuals may communicate with moderate-to-high language skills, although difficulties in social skills may result in communication deficits. Low-functioning individuals may have severe deficiencies in language, resulting in poor communication between the individual and others. Behavioral intervention programs have been developed for ASD, and are frequently adjusted to accommodate specific individual needs. Many of these programs are school-based and aim to support the child in the development of their skills, for use outside the classroom with family and friends. Strides are being made in understanding the factors contributing to the development of ASD, particularly the genetic contributions that may underlie these disorders. Mutant mouse models provide powerful research tools to investigate the genetic factors associated with ASD and its co-morbid disorders. In support, the BTBR T+tf/J mouse strain incorporates ASD-like social and communication deficits and high levels of repetitive behaviors. This commentary briefly reviews the reciprocal relationship between observations made during evidence-based behavioral interventions of high- versus low-functioning children with ASD and the accumulating body of research in autism, including animal studies and basic research models. This reciprocity is one of the hallmarks of the scientific method, such that research may inform behavioral treatments, and observations made during treatment may inform subsequent research. PMID:20093134

  18. Quantum Error Correction

    NASA Astrophysics Data System (ADS)

    Lidar, Daniel A.; Brun, Todd A.

    2013-09-01

    Prologue; Preface; Part I. Background: 1. Introduction to decoherence and noise in open quantum systems Daniel Lidar and Todd Brun; 2. Introduction to quantum error correction Dave Bacon; 3. Introduction to decoherence-free subspaces and noiseless subsystems Daniel Lidar; 4. Introduction to quantum dynamical decoupling Lorenza Viola; 5. Introduction to quantum fault tolerance Panos Aliferis; Part II. Generalized Approaches to Quantum Error Correction: 6. Operator quantum error correction David Kribs and David Poulin; 7. Entanglement-assisted quantum error-correcting codes Todd Brun and Min-Hsiu Hsieh; 8. Continuous-time quantum error correction Ognyan Oreshkov; Part III. Advanced Quantum Codes: 9. Quantum convolutional codes Mark Wilde; 10. Non-additive quantum codes Markus Grassl and Martin Rötteler; 11. Iterative quantum coding systems David Poulin; 12. Algebraic quantum coding theory Andreas Klappenecker; 13. Optimization-based quantum error correction Andrew Fletcher; Part IV. Advanced Dynamical Decoupling: 14. High order dynamical decoupling Zhen-Yu Wang and Ren-Bao Liu; 15. Combinatorial approaches to dynamical decoupling Martin Rötteler and Pawel Wocjan; Part V. Alternative Quantum Computation Approaches: 16. Holonomic quantum computation Paolo Zanardi; 17. Fault tolerance for holonomic quantum computation Ognyan Oreshkov, Todd Brun and Daniel Lidar; 18. Fault tolerant measurement-based quantum computing Debbie Leung; Part VI. Topological Methods: 19. Topological codes Héctor Bombín; 20. Fault tolerant topological cluster state quantum computing Austin Fowler and Kovid Goyal; Part VII. Applications and Implementations: 21. Experimental quantum error correction Dave Bacon; 22. Experimental dynamical decoupling Lorenza Viola; 23. Architectures Jacob Taylor; 24. Error correction in quantum communication Mark Wilde; Part VIII. Critical Evaluation of Fault Tolerance: 25. Hamiltonian methods in QEC and fault tolerance Eduardo Novais, Eduardo Mucciolo and

  19. Fiber coupled single photon receivers based on superconducting detectors for quantum communications and quantum cryptography

    NASA Astrophysics Data System (ADS)

    Smirnov, K. V.; Vachtomin, Yu. B.; Ozhegov, R. V.; Pentin, I. V.; Slivinskaya, E. V.; Korneev, A. A.; Goltsman, G. N.

    2008-11-01

    At present superconducting detectors become increasingly attractive for various practical applications. In this paper we present results on the depelopment of fiber coupled receiver systems for the registration of IR single photons, optimized for telecommunication and quantum-cryptography. These receiver systems were developed on the basis of superconducting single photon detectors (SSPD) of VIS and IR wavelength ranges. The core of the SSPD is a narrow (~100 nm) and long (~0,5 mm) strip in the form of a meander which is patterned from a 4-nm-thick NbN film (TC=10-11 K, jC=~5-7•106 A/cm2); the sensitive area dimensions are 10×10 μm2. The main problem to be solved while the receiver system development was optical coupling of a single-mode fiber (9 microns in diameter) with the SSPD sensitive area. Characteristics of the developed system at the optical input are as follows: quantum efficiency >10 % (at 1.3 μm), >4 % (at 1.55 μm) dark counts rate <=1 s-1; duration of voltage pulse <=5 ns; jitter <=40 ps. The receiver systems have either one or two identical channels (for the case of carrying out correlation measurements) and are made as an insert in a helium storage Dewar.

  20. An upper bound on the second order asymptotic expansion for the quantum communication cost of state redistribution

    NASA Astrophysics Data System (ADS)

    Datta, Nilanjana; Hsieh, Min-Hsiu; Oppenheim, Jonathan

    2016-05-01

    State redistribution is the protocol in which given an arbitrary tripartite quantum state, with two of the subsystems initially being with Alice and one being with Bob, the goal is for Alice to send one of her subsystems to Bob, possibly with the help of prior shared entanglement. We derive an upper bound on the second order asymptotic expansion for the quantum communication cost of achieving state redistribution with a given finite accuracy. In proving our result, we also obtain an upper bound on the quantum communication cost of this protocol in the one-shot setting, by using the protocol of coherent state merging as a primitive.

  1. Advances in high-speed low-latency communications for nanopositioning in advanced microscopy

    NASA Astrophysics Data System (ADS)

    Jordan, Scott C.

    2012-06-01

    We present a comparison of classical and recently developed communications interfacing technologies relevant to scanned imaging. We adopt an applications perspective, with a focus on interfacing techniques as enablers for enhanced resolution, speed, stability, information density or similar benefits. A wealth of such applications have emerged, ranging from nanoscale-stabilized force microscopy yielding 100X resolution improvement thanks to leveraging the latest in interfacing capabilities, to novel approaches in analog interfacing which improve data density and DAC resolution by several orders of magnitude. Our intent is to provide tools to understand, select and implement advanced interfacing to take applications to the next level. We have entered an era in which new interfacing techniques are enablers, in their own right, for novel imaging techniques. For example, clever leveraging of new interfacing technologies has yielded nanoscale stabilization and atomic-force microscopy (AFM) resolution enhancement. To assist in choosing and implementing interfacing strategies that maximize performance and enable new capabilities, we review available interfaces such as USB2, GPIB and Ethernet against the specific needs of positioning for the scanned-imaging community. We spotlight recent developments such as LabVIEW FPGA, which allows non-specialists to quickly devise custom logic and interfaces of unprecedentedly high performance and parallelism. Notable applications are reviewed, including a clever amalgamation of AFM and optical tweezers and a picometer-scaleaccuracy interferometer devised for ultrafine positioning validation. We note the Serial Peripheral Interface (SPI), emerging as a high-speed/low-latency instrumentation interface. The utility of instrument-specific parallel (PIO) and TTL sync/trigger (DIO) interfaces is also discussed. Requirements of tracking and autofocus are reviewed against the time-critical needs of typical applications (to avoid, for example

  2. Single donor electronics and quantum functionalities with advanced CMOS technology

    NASA Astrophysics Data System (ADS)

    Jehl, Xavier; Niquet, Yann-Michel; Sanquer, Marc

    2016-03-01

    Recent progresses in quantum dots technology allow fundamental studies of single donors in various semiconductor nanostructures. For the prospect of applications figures of merits such as scalability, tunability, and operation at relatively large temperature are of prime importance. Beyond the case of actual dopant atoms in a host crystal, similar arguments hold for small enough quantum dots which behave as artificial atoms, for instance for single spin control and manipulation. In this context, this experimental review focuses on the silicon-on-insulator devices produced within microelectronics facilities with only very minor modifications to the current industrial CMOS process and tools. This is required for scalability and enabled by shallow trench or mesa isolation. It also paves the way for real integration with conventional circuits, as illustrated by a nanoscale device coupled to a CMOS circuit producing a radio-frequency drive on-chip. At the device level we emphasize the central role of electrostatics in etched silicon nanowire transistors, which allows to understand the characteristics in the full range from zero to room temperature.

  3. Advancing Unmanned Aircraft Sensor Collection and Communication Capabilities with Optical Communications

    NASA Astrophysics Data System (ADS)

    Lukaczyk, T.

    2015-12-01

    Unmanned aircraft systems (UAS) are now being used for monitoring climate change over both land and seas. Their uses include monitoring of cloud conditions and atmospheric composition of chemicals and aerosols due to pollution, dust storms, fires, volcanic activity and air-sea fluxes. Additional studies of carbon flux are important for various ecosystem studies of both marine and terrestrial environments specifically, and can be related to climate change dynamics. Many measurements are becoming more complex as additional sensors become small enough to operate on more widely available small UAS. These include interferometric radars as well as scanning and fan-beam lidar systems which produce data streams even greater than those of high resolution video. These can be used to precisely map surfaces of the earth, ocean or ice features that are important for a variety of earth system studies. As these additional sensor capabilities are added to UAS the ability to transmit data back to ground or ship monitoring sites is limited by traditional wireless communication protocols. We describe results of tests of optical communication systems that provide significantly greater communication bandwidths for UAS, and discuss both the bandwidth and effective range of these systems, as well as their power and weight requirements both for systems on UAS, as well as those of ground-based receiver stations. We justify our additional use of Delay and Disruption Tolerant Networking (DTN) communication protocols with optical communication methods to ensure security and continuity of command and control operations. Finally, we discuss the implications for receiving, geo-referencing, archiving and displaying data streams from sensors communicated via optical communication to better enable real-time anomaly detection and adaptive sampling capabilities using multiple UAS or other unmanned or manned systems.

  4. Improving the modulation bandwidth of LED by CdSe/ZnS quantum dots for visible light communication.

    PubMed

    Xiao, Xiangtian; Tang, Haodong; Zhang, Tianqi; Chen, Wei; Chen, Wanli; Wu, Dan; Wang, Rui; Wang, Kai

    2016-09-19

    Visible light communication (VLC) is an advanced and high-efficiency wireless communication technology. As one of the most important light sources in VLC, conventional white light emitting diode (WLED) based on Y3Al5O12:Ce3+ (YAG:Ce) phosphor limits the system transmitting rate severely due to its narrow modulation bandwidth. Considering the short fluorescent lifetime of quantum dots (QDs), QD-LEDs with wide modulation bandwidths were designed here to improve the transmitting rate of VLC. CdSe/ZnS core/shell QDs and related luminescent microspheres (LMS) were implemented as light conversion materials for the QD-LEDs. Compared with conventional phosphor WLED, the proposed QD-LED and QD-WLED reached maximum improvement on modulation bandwidth at 74.19% and 67.75% respectively. Furthermore, mathematical modeling of smearing was analyzed to establish the relationship between fluorescent lifetime and modulation bandwidth. Our findings will provide an effective solution of white LEDs for high speed VLC. PMID:27661896

  5. Improving the modulation bandwidth of LED by CdSe/ZnS quantum dots for visible light communication.

    PubMed

    Xiao, Xiangtian; Tang, Haodong; Zhang, Tianqi; Chen, Wei; Chen, Wanli; Wu, Dan; Wang, Rui; Wang, Kai

    2016-09-19

    Visible light communication (VLC) is an advanced and high-efficiency wireless communication technology. As one of the most important light sources in VLC, conventional white light emitting diode (WLED) based on Y3Al5O12:Ce3+ (YAG:Ce) phosphor limits the system transmitting rate severely due to its narrow modulation bandwidth. Considering the short fluorescent lifetime of quantum dots (QDs), QD-LEDs with wide modulation bandwidths were designed here to improve the transmitting rate of VLC. CdSe/ZnS core/shell QDs and related luminescent microspheres (LMS) were implemented as light conversion materials for the QD-LEDs. Compared with conventional phosphor WLED, the proposed QD-LED and QD-WLED reached maximum improvement on modulation bandwidth at 74.19% and 67.75% respectively. Furthermore, mathematical modeling of smearing was analyzed to establish the relationship between fluorescent lifetime and modulation bandwidth. Our findings will provide an effective solution of white LEDs for high speed VLC.

  6. Baseband processor development for the Advanced Communications Satellite Program

    NASA Technical Reports Server (NTRS)

    Moat, D.; Sabourin, D.; Stilwell, J.; Mccallister, R.; Borota, M.

    1982-01-01

    An onboard-baseband-processor concept for a satellite-switched time-division-multiple-access (SS-TDMA) communication system was developed for NASA Lewis Research Center. The baseband processor routes and controls traffic on an individual message basis while providing significant advantages in improved link margins and system flexibility. Key technology developments required to prove the flight readiness of the baseband-processor design are being verified in a baseband-processor proof-of-concept model. These technology developments include serial MSK modems, Clos-type baseband routing switch, a single-chip CMOS maximum-likelihood convolutional decoder, and custom LSL implementation of high-speed, low-power ECL building blocks.

  7. R and D limited partnerships (possible applications in advanced communications satellite technology experiment program)

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Typical R&D limited partnership arrangements, advantages and disadvantages of R&D limited partnership (RDLPs) and antitrust and tax implications are described. A number of typical forms of RDLPs are described that may be applicable for use in stimulating R&D and experimental programs using the advanced communications technology satellite. The ultimate goal is to increase the rate of market penetration of goods and/or services based upon advanced satellite communications technology. The conditions necessary for these RDLP forms to be advantageous are outlined.

  8. Advanced quantum cascade laser transmitter architectures and infrared photonics development

    SciTech Connect

    Anheier, Norman C.; Allen, Paul J.; Myers, Tanya L.

    2004-08-01

    Quantum cascade lasers (QCLs) provide a viable infrared laser source for a new class of laser transmitters capable of meeting the performance requirements for a variety of national security and civilian applications. The high output power, small size, and superb stability and modulation characteristics of QCLs make them amenable for integration as transmitters into ultra-sensitive, ultra-selective point sampling and remote short-range chemical sensors. This paper reports on the current development in infrared photonics that provides a pathway for QCL transmitter miniaturization. This research has produced infrared waveguide-based optical components in chalcogenide glass using both direct-laser writing and holographic exposure techniques. We discuss here the design and fabrication concepts and capabilities required to produce integrated waveguides, waveguide couplers, and other photonic devices.

  9. Cryptanalysis and improvement of quantum broadcast communication and authentication protocol with a quantum one-time pad

    NASA Astrophysics Data System (ADS)

    Liu, Zhi-Hao; Chen, Han-Wu

    2016-08-01

    The security of quantum broadcast communication (QBC) and authentication protocol based on Greenberger-Horne-Zeilinger (GHZ) state and quantum one-time pad is analyzed. It is shown that there are some security issues in this protocol. Firstly, an external eavesdropper can take the intercept-measure-resend attack strategy to eavesdrop on 0.369 bit of every bit of the identity string of each receiver without being detected. Meanwhile, 0.524 bit of every bit of the secret message can be eavesdropped on without being detected. Secondly, an inner receiver can take the intercept-measure-resend attack strategy to eavesdrop on half of the identity string of the other’s definitely without being checked. In addition, an alternative attack called the CNOT-operation attack is discussed. As for the multi-party QBC protocol, the attack efficiency increases with the increase of the number of users. Finally, the QBC protocol is improved to a secure one. Project supported by the National Natural Science Foundation of China (Grant Nos. 61502101 and 61170321), the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20140651), the Research Fund for the Doctoral Program of Higher Education, China (Grant No. 20110092110024), and the Project Funded by PAPD and CICAEET.

  10. Cryptanalysis and improvement of quantum broadcast communication and authentication protocol with a quantum one-time pad

    NASA Astrophysics Data System (ADS)

    Liu, Zhi-Hao; Chen, Han-Wu

    2016-08-01

    The security of quantum broadcast communication (QBC) and authentication protocol based on Greenberger–Horne–Zeilinger (GHZ) state and quantum one-time pad is analyzed. It is shown that there are some security issues in this protocol. Firstly, an external eavesdropper can take the intercept–measure–resend attack strategy to eavesdrop on 0.369 bit of every bit of the identity string of each receiver without being detected. Meanwhile, 0.524 bit of every bit of the secret message can be eavesdropped on without being detected. Secondly, an inner receiver can take the intercept–measure–resend attack strategy to eavesdrop on half of the identity string of the other’s definitely without being checked. In addition, an alternative attack called the CNOT-operation attack is discussed. As for the multi-party QBC protocol, the attack efficiency increases with the increase of the number of users. Finally, the QBC protocol is improved to a secure one. Project supported by the National Natural Science Foundation of China (Grant Nos. 61502101 and 61170321), the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20140651), the Research Fund for the Doctoral Program of Higher Education, China (Grant No. 20110092110024), and the Project Funded by PAPD and CICAEET.

  11. Communication system technology for demonstration of BB84 quantum key distribution in optical aircraft downlinks

    NASA Astrophysics Data System (ADS)

    Moll, Florian; Nauerth, Sebastian; Fuchs, Christian; Horwath, Joachim; Rau, Markus; Weinfurter, Harald

    2012-10-01

    Quantum Key Distribution (QKD), either fiber based or free-space, allows for provably secure key distribution solely based on the laws of quantum mechanics. Feasibility of QKD systems in aircraft-ground links was demonstrated with a successful key exchange. Experiment flights were undertaken during night time at the site of the German Aerospace Center (DLR) Oberpfaffenhofen, Germany. The aircraft was a Dornier 228 equipped with a laser communication terminal, originally designed for optical data downlinks with intensity modulation and direct detection. The counter terminal on ground was an optical ground station with a 40 cm Cassegrain type receiver telescope. Alice and Bob, as the transmitter and receiver systems usually are called in QKD, were integrated in the flight and ground terminals, respectively. A second laser source with 1550 nm wavelength was used to transmit a 100 MHz signal for synchronization of the two partners. The so called BB84 protocol, here implemented with faint polarization encoded pulses at 850nm wavelength, was applied as key generation scheme. Within two flights, measurements of the QKD and communication channel could be obtained with link distance of 20 km. After link acquisition, the tracking systems in the aircraft and on ground were able to keep lock of the narrow QKD beam. Emphasis of this paper is put on presentation of the link technology, i.e. link design and modifications of the communication terminals. First analysis of link attenuation, performance of the QKD system and scintillation of the sync signal is also addressed.

  12. Advanced Communications Technology Satellite (ACTS): Design and on-orbit performance measurements

    NASA Technical Reports Server (NTRS)

    Gargione, F.; Acosta, R.; Coney, T.; Krawczyk, R.

    1995-01-01

    The Advanced Communications Technology Satellite (ACTS), developed and built by Lockheed Martin Astro space for the NASA Lewis Research Center, was launched in September 1993 on the shuttle STS 51 mission. ACTS is a digital experimental communications test bed that incorporates gigahertz bandwidth transponders operating at Ka band, hopping spot beams, on-board storage and switching, and dynamic rain fade compensation. This paper describes the ACTS enabling technologies, the design of the communications payload, the constraints imposed on the spacecraft bus, and the measurements conducted to verify the performance of the system in orbit.

  13. Presentations of the Ninth Advanced Communications Technology Satellite Propagation Studies Workshop (APSW IX)

    NASA Technical Reports Server (NTRS)

    Golshan, Nasser (Editor)

    1997-01-01

    The Advanced Communications Technology Satellite Propagation Studies Workshop (APSW) is convened each year to present the results of the ACTS Propagation Campaign. Representatives from the satellite communications (satcom) industry, academia, and government are invited to APSW for discussions and exchange of information. The ACTS Propagation campaign is completing three years of Ka-Band data collection at seven sites in North America. Through this effort, NASA is making a major contribution to growth of satcom services by providing timely propagation data and models for predicting the performance of Ka-Band satellite communications systems.

  14. A Bidirectional Quantum Secure Direct Communication Protocol Based on Five-Particle Cluster State

    NASA Astrophysics Data System (ADS)

    Chang, Yan; Zhang, Shi-Bin; Yan, Li-Li

    2013-09-01

    To transmit a message safely, five-particle cluster state particles are used to construct a bidirectional quantum secure direct communication protocol. Five-particle cluster state particles are used for both detecting eavesdroppers and transmitting secret messages. All of the five-particle cluster states' photons for detection are mixed to the sending sequence to detect eavesdroppers. The detection rate approaches 88% per qubit. The five-particle cluster states needed are only one fifth of the photons in the sending sequence. In this protocol, there is no photon carrying secret information transmitting in quantum channel, and the classical XOR operation which serves as a one-time-pad is used to ensure the security of the protocol. Compared with three photons of each five-particle cluster state as detection photons, the five photons in this study will decrease the five-particle cluster states needed for detection greatly.

  15. Satellite switched FDMA advanced communication technology satellite program

    NASA Technical Reports Server (NTRS)

    Atwood, S.; Higton, G. H.; Wood, K.; Kline, A.; Furiga, A.; Rausch, M.; Jan, Y.

    1982-01-01

    The satellite switched frequency division multiple access system provided a detailed system architecture that supports a point to point communication system for long haul voice, video and data traffic between small Earth terminals at Ka band frequencies at 30/20 GHz. A detailed system design is presented for the space segment, small terminal/trunking segment at network control segment for domestic traffic model A or B, each totaling 3.8 Gb/s of small terminal traffic and 6.2 Gb/s trunk traffic. The small terminal traffic (3.8 Gb/s) is emphasized, for the satellite router portion of the system design, which is a composite of thousands of Earth stations with digital traffic ranging from a single 32 Kb/s CVSD voice channel to thousands of channels containing voice, video and data with a data rate as high as 33 Mb/s. The system design concept presented, effectively optimizes a unique frequency and channelization plan for both traffic models A and B with minimum reorganization of the satellite payload transponder subsystem hardware design. The unique zoning concept allows multiple beam antennas while maximizing multiple carrier frequency reuse. Detailed hardware design estimates for an FDMA router (part of the satellite transponder subsystem) indicate a weight and dc power budget of 353 lbs, 195 watts for traffic model A and 498 lbs, 244 watts for traffic model B.

  16. Advanced space communications architecture study. Volume 2: Technical report

    NASA Technical Reports Server (NTRS)

    Horstein, Michael; Hadinger, Peter J.

    1987-01-01

    The technical feasibility and economic viability of satellite system architectures that are suitable for customer premise service (CPS) communications are investigated. System evaluation is performed at 30/20 GHz (Ka-band); however, the system architectures examined are equally applicable to 14/11 GHz (Ku-band). Emphasis is placed on systems that permit low-cost user terminals. Frequency division multiple access (FDMA) is used on the uplink, with typically 10,000 simultaneous accesses per satellite, each of 64 kbps. Bulk demodulators onboard the satellite, in combination with a baseband multiplexer, convert the many narrowband uplink signals into a small number of wideband data streams for downlink transmission. Single-hop network interconnectivity is accomplished via downlink scanning beams. Each satellite is estimated to weigh 5600 lb and consume 6850W of power; the corresponding payload totals are 1000 lb and 5000 W. Nonrecurring satellite cost is estimated at $110 million, with the first-unit cost at $113 million. In large quantities, the user terminal cost estimate is $25,000. For an assumed traffic profile, the required system revenue has been computed as a function of the internal rate of return (IRR) on invested capital. The equivalent user charge per-minute of 64-kbps channel service has also been determined.

  17. Advanced space communications architecture study. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Horstein, Michael; Hadinger, Peter J.

    1987-01-01

    The technical feasibility and economic viability of satellite system architectures that are suitable for Customer Premise Service (CPS) communications is investigated. System evaluation is performed at 30/20 GHz (Ka-band); however, the system architectures examined are equally applicable to 14/11 GHz (Ku-band). Emphasis is placed on system that permit low cost user terminals. Frequency Division Multiple Access (FDMA) is used on the uplink, with typically 10,000 simultaneous accesses per satellite, each of 64 kbps. Bulk demodulators onboard the satellite, in combination with a baseband multiplexer, convert the many narrowband uplink signals into a small number of wideband data streams for downlink transmission. Single hop network interconnectivity is accomplished through use of downlink scanning beams. Each satellite is estimated to weigh 5600 lb and consume 6850W of power; the corresponding payload totals are 1000 lb and 5000W. Nonrecurring satellite cost is estimated at $110 million, with the first unit cost at $113 million. In large quantities, the user terminal cost estimate is $25,000.

  18. Dynamic (2, 3) Threshold Quantum Secret Sharing of Secure Direct Communication

    NASA Astrophysics Data System (ADS)

    Lai, Hong; Orgun, A. Mehmet; Xiao, Jing-Hua; Pieprzyk, Josef; Xue, Li-Yin

    2015-04-01

    In this paper, we show that a (2, 3) discrete variable threshold quantum secret sharing scheme of secure direct communication can be achieved based on recurrence using the same devices as in BB84. The scheme is devised by first placing the shares of smaller secret pieces into the shares of the largest secret piece, converting the shares of the largest secret piece into corresponding quantum state sequences, inserting nonorthogonal state particles into the quantum state sequences with the purpose of detecting eavesdropping, and finally sending the new quantum state sequences to the three participants respectively. Consequently, every particle can on average carry up to 1.5-bit messages due to the use of recurrence. The control codes are randomly prepared using the way to generate fountain codes with pre-shared source codes between Alice and Bob, making three participants can detect eavesdropping by themselves without sending classical messages to Alice. Due to the flexible encoding, our scheme is also dynamic, which means that it allows the participants to join and leave freely. Supported in part by an International Macquarie University Research Excellence Scholarship (iMQRES), Australian Research Council Grant DP0987734. This work is also supported by the National Basic Research Program of China (973 Program) under Grant No. 2010CB923200, the National Natural Science Foundation of China under No. 61377067, Fund of State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications, China, National Natural Science Foundation of China under Grant Nos. 61202362, 61262057, 61472433, and China Postdoctora Science Foundation under Grant No. 2013M542560

  19. Quantum dots in biomedical applications: advances and challenges

    NASA Astrophysics Data System (ADS)

    Cinteza, Ludmila Otilia

    2010-09-01

    In the past two decades, nanotechnology has made great progress in generating novel materials with superior properties. Quantum dots (QDs) are an example of such materials. With unique optical properties, they have proven to be useful in a wide range of applications in life sciences, especially as a better alternative to overcome the shortcomings of conventional fluorophores. Current progress in the synthesis of biocompatible QDs allows for the possibility of producing a large variety of semiconductor nanocrystals in terms of size, surface functionality, bioconjugation, and targeting facilities. Strategies to enhance the water-dispersibility and biocompatibility of these nanoparticles have been developed, involving various encapsulation techniques and surface functionalization. The major obstacle in the clinical use of QDs remains their toxicity, and the systematic investigation on harmful effects of QDs both to humans and to the environment has become critical. Many examples of the experimental use of QDs prove their far-reaching potential for the study of intracellular processes at the molecular level, high resolution cellular imaging, and in vivo observation of cell trafficking. Biosensing methods based on QD bioconjugates proved to be successful in rapid detection of pathogens, and significant improvements are expected in early cancer diagnostic, non-conventional therapy of cancer and neurodegenerative diseases.

  20. A revised controlled deterministic secure quantum communication with five-photon entangled state

    NASA Astrophysics Data System (ADS)

    Xiu, Xiao-Ming; Dong, Li; Gao, Ya-Jun; Chi, Feng; Ren, Yuan-Peng; Liu, Hui-Wei

    2010-01-01

    A revised controlled deterministic secure quantum communication protocol using five-photon entangled state is proposed. It amends the security loopholes pointed by Qin et al. in [S.J. Qin, Q.Y. Wen, L.M. Meng, F.C. Zhu, Opt. Commun. 282 (2009) 2656] in the original protocol proposed by Xiu et al. in [X.M. Xiu, L. Dong, Y.J. Gao, F. Chi, Opt. Commun. 282 (2009) 333]. The security loopholes are solved by using order rearrangement of transmission photons and two-step security test.

  1. Reexamining the Security of Controlled Quantum Secure Direct Communication by Using Four Particle Cluster States

    NASA Astrophysics Data System (ADS)

    Qin, Su-Juan

    2012-09-01

    A controlled quantum secure direct communication protocol (Zhang et al. in Int. J. Theor. Phys. 48:2971-2976, 2009) by using four particle cluster states was proposed recently. Yang et al. presented an attack with fake entangled particles (FEP attack) and gave an improvement (Yang et al. in Int. J. Theor. Phys. 50:395-400, 2010). In this paper, we reexamine the protocol's security and discover that, Bob can also take a different attack, disentanglement attack, to obtain Alice's secret message without controller's permission. Moreover, our attack strategy also works for Yang's improvement.

  2. Advanced Communication and Control Solutions of Distributed Energy Resources (DER)

    SciTech Connect

    Asgeirsson, Haukur; Seguin, Richard; Sherding, Cameron; de Bruet, Andre, G.; Broadwater, Robert; Dilek, Murat

    2007-01-10

    This report covers work performed in Phase II of a two phase project whose objective was to demonstrate the aggregation of multiple Distributed Energy Resources (DERs) and to offer them into the energy market. The Phase I work (DE-FC36-03CH11161) created an integrated, but distributed, system and procedures to monitor and control multiple DERs from numerous manufacturers connected to the electric distribution system. Procedures were created which protect the distribution network and personnel that may be working on the network. Using the web as the communication medium for control and monitoring of the DERs, the integration of information and security was accomplished through the use of industry standard protocols such as secure SSL,VPN and ICCP. The primary objective of Phase II was to develop the procedures for marketing the power of the Phase I aggregated DERs in the energy market, increase the number of DER units, and implement the marketing procedures (interface with ISOs) for the DER generated power. The team partnered with the Midwest Independent System Operator (MISO), the local ISO, to address the energy market and demonstrate the economic dispatch of DERs in response to market signals. The selection of standards-based communication technologies offers the ability of the system to be deployed and integrated with other utilities’ resources. With the use of a data historian technology to facilitate the aggregation, the developed algorithms and procedures can be verified, audited, and modified. The team has demonstrated monitoring and control of multiple DERs as outlined in phase I report including procedures to perform these operations in a secure and safe manner. In Phase II, additional DER units were added. We also expanded on our phase I work to enhance communication security and to develop the market model of having DERs, both customer and utility owned, participate in the energy market. We are proposing a two-part DER energy market model--a utility

  3. Quantum phase communication channels in the presence of static and dynamical phase diffusion

    NASA Astrophysics Data System (ADS)

    Trapani, Jacopo; Teklu, Berihu; Olivares, Stefano; Paris, Matteo G. A.

    2015-07-01

    We address quantum communication channels based on phase modulation of coherent states and analyze in detail the effects of static and dynamical (stochastic) phase diffusion. We evaluate mutual information for an ideal phase receiver and for a covariant phase-space-based receiver, and compare their performances by varying the number of symbols in the alphabet and/or the overall energy of the channel. Our results show that phase communication channels are generally robust against phase noise, especially for large alphabets in the low-energy regime. In the presence of dynamical (non-Markovian) noise the mutual information is preserved by the time correlation of the environment, and when the noise spectra are detuned with respect to the information carrier, revivals of mutual information appear.

  4. Prospects for Significant Theoretical Advances in Communication: The Role of the Interesting Question.

    ERIC Educational Resources Information Center

    Gouran, Dennis S.

    This paper discusses ways in which the field of speech communication can be advanced. The first half of the paper characterizes the objectivist and subjectivist views of how knowledge is acquired and the forms of inquiry to which these views have led. The remainder of the paper demonstrates the role that the "interesting question" (one for which…

  5. Application of advanced on-board processing concepts to future satellite communications systems

    NASA Technical Reports Server (NTRS)

    Katz, J. L.; Hoffman, M.; Kota, S. L.; Ruddy, J. M.; White, B. F.

    1979-01-01

    An initial definition of on-board processing requirements for an advanced satellite communications system to service domestic markets in the 1990's is presented. An exemplar system architecture with both RF on-board switching and demodulation/remodulation baseband processing was used to identify important issues related to system implementation, cost, and technology development.

  6. Health Care Professionals' Death Attitudes, Experiences, and Advance Directive Communication Behavior

    ERIC Educational Resources Information Center

    Black, Kathy

    2007-01-01

    The study surveyed 135 health care professionals (74 nurses, 32 physicians, and 29 social workers) to examine their personal death attitudes and experiences in relation to their reported advance directive communication practice behavior. Negative correlations were found between collaborating with other health care professionals regarding the…

  7. Beyond Advanced Gravitational Wave Detectors: Beating the Quantum Limit with Squeezed States of Light

    NASA Astrophysics Data System (ADS)

    Barsotti, Lisa

    2013-04-01

    After two decades of technology development, the first direct observation of gravitational waves appears to be imminent. Ground-based interferometric gravitational wave detectors world-wide are about to come back on-line after a major upgrade aimed to significantly improve their sensitivity. As these advanced detectors become a reality, the gravitational wave community is looking at new ways of further expanding their astrophysical reach. The quantum nature of light imposes a fundamental limit to the sensitivity that gravitational wave detectors can achieve, due to statistical fluctuations in the arrival time of photons at the interferometer output (shot noise) and the recoil of the mirrors due to radiation pressure noise. In this talk I will show how mature technology can be used to push interferometric precision measurement beyond the standard quantum limit by means of squeezed states of light, and current ideas on how to integrate this technology into the Advanced detectors of the Laser Interferometer Gravitational wave Observatory (LIGO).

  8. Application of Advanced Atomic Force Microscopy Techniques to Study Quantum Dots and Bio-materials

    NASA Astrophysics Data System (ADS)

    Guz, Nataliia

    In recent years, there has been an increase in research towards micro- and nanoscale devices as they have proliferated into diverse areas of scientific exploration. Many of the general fields of study that have greatly affected the advancement of these devices includes the investigation of their properties. The sensitivity of Atomic Force Microscopy (AFM) allows detecting charges up to the single electron value in quantum dots in ambient conditions, the measurement of steric forces on the surface of the human cell brush, determination of cell mechanics, magnetic forces, and other important properties. Utilizing AFM methods, the fast screening of quantum dot efficiency and the differences between cancer, normal (healthy) and precancer (immortalized) human cells has been investigated. The current research using AFM techniques can help to identify biophysical differences of cancer cells to advance our understanding of the resistance of the cells against the existing medicine.

  9. An Extremely Low Power Quantum Optical Communication Link for Autonomous Robotic Explorers

    NASA Technical Reports Server (NTRS)

    Lekki, John; Nguyen, Quang-Viet; Bizon, Tom; Nguyen, Binh; Kojima, Jun

    2007-01-01

    One concept for planetary exploration involves using many small robotic landers that can cover more ground than a single conventional lander. In addressing this vision, NASA has been challenged in the National Nanotechnology Initiative to research the development of miniature robots built from nano-sized components. These robots have very significant challenges, such as mobility and communication, given the small size and limited power generation capability. The research presented here has been focused on developing a communications system that has the potential for providing ultra-low power communications for robots such as these. In this paper an optical communications technique that is based on transmitting recognizable sets of photons is presented. Previously pairs of photons that have an entangled quantum state have been shown to be recognizable in ambient light. The main drawback to utilizing entangled photons is that they can only be generated through a very energy inefficient nonlinear process. In this paper a new technique that generates sets of photons from pulsed sources is described and an experimental system demonstrating this technique is presented. This technique of generating photon sets from pulsed sources has the distinct advantage in that it is much more flexible and energy efficient, and is well suited to take advantage of the very high energy efficiencies that are possible when using nano scale sources. For these reasons the communication system presented in this paper is well suited for use in very small, low power landers and rovers. In this paper a very low power optical communications system for miniature robots, as small as 1 cu cm is addressed. The communication system is a variant of photon counting communications. Instead of counting individual photons the system only counts the arrival of time coincident sets of photons. Using sets of photons significantly decreases the bit error rate because they are highly identifiable in the

  10. Fault tolerant deterministic secure quantum communication using logical Bell states against collective noise

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Liu, Jian-Wei; Chen, Xiu-Bo; Bi, Ya-Gang; Shang, Tao

    2015-04-01

    This study proposes two novel fault tolerant deterministic secure quantum communication (DSQC) schemes resistant to collective noise using logical Bell states. Either DSQC scheme is constructed based on a new coding function, which is designed by exploiting the property of the corresponding logical Bell states immune to collective-dephasing noise and collective-rotation noise, respectively. The secret message can be encoded by two simple unitary operations and decoded by merely performing Bell measurements, which can make the proposed scheme more convenient in practical applications. Moreover, the strategy of one-step quanta transmission, together with the technique of decoy logical qubits checking not only reduces the influence of other noise existing in a quantum channel, but also guarantees the security of the communication between two legitimate users. The final analysis shows that the proposed schemes are feasible and robust against various well-known attacks over the collective noise channel. Project supported by the National Natural Science Foundation of China (Grant Nos. 61272501, 61272514, 61170272, 61472048, 61402058, 61121061, and 61411146001), the Program for New Century Excellent Talents in University of China (Grant No. NCET-13-0681), the National Development Foundation for Cryptological Research (Grant No. MMJJ201401012), the Fok Ying Tong Education Foundation (Grant No. 131067), the Natural Science Foundation of Beijing (Grant Nos. 4132056 and 4152038), the Postdoctoral Science Foundation of China (Grant No. 2014M561826), and the National Key Basic Research Program, China (Grant No. 2012CB315905)

  11. Capacity of optical communication in loss and noise with general quantum Gaussian receivers

    NASA Astrophysics Data System (ADS)

    Takeoka, Masahiro; Guha, Saikat

    2014-04-01

    Laser-light (coherent-state) modulation is sufficient to achieve the ultimate (Holevo) capacity of classical communication over a lossy and noisy optical channel, but requires a receiver that jointly detects long modulated code words with highly nonlinear quantum operations, which are near-impossible to realize using current technology. We analyze the capacity of the lossy-noisy optical channel when the transmitter uses coherent-state modulation but the receiver is restricted to a general quantum-limited Gaussian receiver, i.e., one that may involve arbitrary combinations of Gaussian operations [passive linear optics: beam splitters and phase shifters; second-order nonlinear optics (or active linear optics): squeezers, along with homodyne or heterodyne detection measurements] and any amount of classical feedforward within the receiver. Under these assumptions, we show that the Gaussian receiver that attains the maximum mutual information is either homodyne detection, heterodyne detection, or time sharing between the two, depending upon the received power level. In other words, our result shows that to exceed the theoretical limit of conventional coherent optical communication, one has to incorporate non-Gaussian, i.e., third- or higher-order nonlinear operations in the receiver. Finally we compare our Gaussian receiver limit with experimentally feasible non-Gaussian receivers and show that in the regime of low received photon flux, it is possible to overcome the Gaussian receiver limit by relatively simple non-Gaussian receivers based on photon counting.

  12. Metropolitan all-pass and inter-city quantum communication network.

    PubMed

    Chen, Teng-Yun; Wang, Jian; Liang, Hao; Liu, Wei-Yue; Liu, Yang; Jiang, Xiao; Wang, Yuan; Wan, Xu; Cai, Wei-Qi; Ju, Lei; Chen, Luo-Kan; Wang, Liu-Jun; Gao, Yuan; Chen, Kai; Peng, Cheng-Zhi; Chen, Zeng-Bing; Pan, Jian-Wei

    2010-12-20

    We have demonstrated a metropolitan all-pass quantum communication network in field fiber for four nodes. Any two nodes of them can be connected in the network to perform quantum key distribution (QKD). An optical switching module is presented that enables arbitrary 2-connectivity among output ports. Integrated QKD terminals are worked out, which can operate either as a transmitter, a receiver, or even both at the same time. Furthermore, an additional link in another city of 60 km fiber (up to 130 km) is seamless integrated into this network based on a trusted relay architecture. On all the links, we have implemented protocol of decoy state scheme. All of necessary electrical hardware, synchronization, feedback control, network software, execution of QKD protocols are made by tailored designing, which allow a completely automatical and stable running. Our system has been put into operation in Hefei in August 2009, and publicly demonstrated during an evaluation conference on quantum network organized by the Chinese Academy of Sciences on August 29, 2009. Real-time voice telephone with one-time pad encoding between any two of the five nodes (four all-pass nodes plus one additional node through relay) is successfully established in the network within 60 km. PMID:21196999

  13. High-efficiency atomic entanglement concentration for quantum communication network assisted by cavity QED

    NASA Astrophysics Data System (ADS)

    Wang, Guan-Yu; Li, Tao; Deng, Fu-Guo

    2015-04-01

    Quantum entanglement is the key resource in quantum information processing, especially in quantum communication network. However, affected by the environment noise, the maximally entangled states usually collapse into nonmaximally entangled ones or even mixed states. Here we present two high-efficiency schemes to complete the entanglement concentration of nonlocal two-atom systems. Our first scheme is used to concentrate the nonlocal atomic systems in the partially entangled states with known parameters, and it has the optimal success probability. The second scheme is used to concentrate the entanglement of the nonlocal two-atom systems in the partially entangled states with unknown parameters. Compared with the other schemes for the entanglement concentration of atomic systems, our two protocols are more efficient and practical. They require only an ancillary single photon to judge whether they succeed or not, and they work in a heralded way with detection inefficiency and absence of sophisticated single-photon detectors in practical applications. Moreover, they are insensitive to both the cavity decay and atomic spontaneous emission.

  14. Advancing the art of satellite communications - Foreign competition spurs NASA Satcom research

    NASA Astrophysics Data System (ADS)

    Bulloch, C.

    1985-01-01

    Major advances in satellite communications technology in the US and Japan are detailed. Japan's Ka-band services aboard CS-2a and CS-2b, launched in 1973, are discussed, as well as plans for the ECS-2 and ACTS-E (Advanced Communications Technology Satellite) experimental projects. The ACTS-E would carry both a broadcasting payload operating at 27/22 GHz and a communication payload using the 50/40 GHz band. Japan's fourth generation CS-4, for start-up in the first half of the 1990's, is described as a 2-ton craft carrying 60-70 transponders, and providing capacity for up to 100,000 equivalent two-way voice channels via 10 or 20 scanning spotbeams. NASA's new programs are described as well, including the ACTS program, with a communications payload embodying signal-processing, message-routing, and traffic-management techniques, and the MSAT program, concentrating on narrow-band transmissions. Included are the technical description, operational parameters, and schematic layout of NASA's ACTS, and block diagrams of baseband processor for low burst rate communications switching on the ACTS.

  15. [Advances in sensor node and wireless communication technology of body sensor network].

    PubMed

    Lin, Weibing; Lei, Sheng; Wei, Caihong; Li, Chunxiang; Wang, Cang

    2012-06-01

    With the development of the wireless communication technology, implantable biosensor technology, and embedded system technology, Body Sensor Network (BSN) as one branch of wireless sensor networks and important part of the Internet of things has caught more attention of researchers and enterprises. This paper offers the basic concept of the BSN and analyses the related research. We focus on sensor node and wireless communication technology from perspectives of technology challenges, research advance and development trend in the paper. Besides, we also present a relative overview of domestic and overseas projects for the BSN. PMID:22826960

  16. Network management and signalling standards for CCSDS advanced orbiting system communication systems

    NASA Astrophysics Data System (ADS)

    Pietras, John

    The Consultative Committee for Space Data Systems (CCSDS) is an international organization chartered to develop and adopt communications protocols and data processing standards suitable for use in space-related communication and data processing systems. This paper briefly describes the CCSDS network management environment and reviews the current status of CCSDS recommendations for network management functional capability, use of internal standard for network management, and composition of signaling systems in support of the advanced orbiting systems services typified by the international Space Station Freedom Program. A timetable for future work in this area is presented.

  17. M-health medical video communication systems: an overview of design approaches and recent advances.

    PubMed

    Panayides, A S; Pattichis, M S; Constantinides, A G; Pattichis, C S

    2013-01-01

    The emergence of the new, High Efficiency Video Coding (HEVC) standard, combined with wide deployment of 4G wireless networks, will provide significant support toward the adoption of mobile-health (m-health) medical video communication systems in standard clinical practice. For the first time since the emergence of m-health systems and services, medical video communication systems can be deployed that can rival the standards of in-hospital examinations. In this paper, we provide a thorough overview of today's advancements in the field, discuss existing approaches, and highlight the future trends and objectives.

  18. An advanced satellite communication system for ISDN subscriber and trunk applications - DYANET-II

    NASA Astrophysics Data System (ADS)

    Otsu, Toru; Umehira, Masahiro; Onuki, Masafumi; Nakashima, Hiroshi

    1992-03-01

    This paper describes an advanced satellite communication system for ISDN subscriber and trunk applications that is integrated into a terrestrial ISDN. The system concept of DYANET (DYnamic channel Assigning and routing satellite aided digital NETwork) has been extended to a new platform called DYANET-II which allows satellite communications to be applied to ISDN subscriber lines as well as trunk circuits. New network control technologies have been developed to achieve efficient satellite channel utilization and to ensure a single hop connection of a satellite channel without modifying existing networks. Moreover, compact earth station equipment has been newly developed for use on customer premises.

  19. Information Leakage Problem in Efficient Bidirectional Quantum Secure Direct Communication with Single Photons in Both Polarization and Spatial-Mode Degrees of Freedom

    NASA Astrophysics Data System (ADS)

    Liu, Zhi-Hao; Chen, Han-Wu; Liu, Wen-Jie

    2016-06-01

    The information leakage problem in the efficient bidirectional quantum secure direct communication protocol with single photons in both polarization and spatial-mode degrees of freedom is pointed out. Next, a way to revise this protocol to a truly secure one is given. We hope people pay more attention to the information leakage problem in order to design truly secure quantum communication protocols.

  20. Proceedings of the Workshop on Advanced Network and Technology Concepts for Mobile, Micro, and Personal Communications

    NASA Technical Reports Server (NTRS)

    Paul, Lori (Editor)

    1991-01-01

    The Workshop on Advanced Network and Technology Concepts for Mobile, Micro, and Personal Communications was held at NASA's JPL Laboratory on 30-31 May 1991. It provided a forum for reviewing the development of advanced network and technology concepts for turn-of-the-century telecommunications. The workshop was organized into three main categories: (1) Satellite-Based Networks (L-band, C-band, Ku-band, and Ka-band); (2) Terrestrial-Based Networks (cellular, CT2, PCN, GSM, and other networks); and (3) Hybrid Satellite/Terrestrial Networks. The proceedings contain presentation papers from each of the above categories.

  1. Netscape Communicator 4.5. Volume II: Beyond the Basics. Advanced Searches, Multimedia, and Composing a Web Page.

    ERIC Educational Resources Information Center

    Gallo, Gail; Wichowski, Chester P.

    This second of two guides on Netscape Communicator 4.5 contains six lessons on advanced searches, multimedia, and composing a World Wide Web page. Lesson 1 is a review of the Navigator window, toolbars, and menus. Lesson 2 covers AltaVista's advanced search tips, searching for information excluding certain text, and advanced and nested Boolean…

  2. Proceedings of the Eleventh Advanced Communications Technology Satellite Propagation Studies Workshop (APSW 11)

    NASA Technical Reports Server (NTRS)

    Golshan, Nasser (Editor); Ho, Christian (Editor)

    1998-01-01

    The Advanced Communications Technology Satellite Propagation Studies Workshop (APSW) is convened each year to present the results of the Advanced Communications Technology Satellite (ACTS) Ka-band propagation campaign. Representatives from the space community including industry, academia, and government who are interested in radiowave propagation at Ka-band are invited to APSW for discussions and exchange of information. The ACTS Propagation campaign will complete five years of Ka-Band data collection at seven sites in North America by December 31, 1998. Through this effort, NASA is making a major contribution to the effective utilization of this band by providing timely propagation data and models for predicting the performance of Ka-band links between space and ground.

  3. Mission science value-cost savings from the Advanced Imaging Communication System (AICS)

    NASA Technical Reports Server (NTRS)

    Rice, R. F.

    1984-01-01

    An Advanced Imaging Communication System (AICS) was proposed in the mid-1970s as an alternative to the Voyager data/communication system architecture. The AICS achieved virtually error free communication with little loss in the downlink data rate by concatenating a powerful Reed-Solomon block code with the Voyager convolutionally coded, Viterbi decoded downlink channel. The clean channel allowed AICS sophisticated adaptive data compression techniques. Both Voyager and the Galileo mission have implemented AICS components, and the concatenated channel itself is heading for international standardization. An analysis that assigns a dollar value/cost savings to AICS mission performance gains is presented. A conservative value or savings of $3 million for Voyager, $4.5 million for Galileo, and as much as $7 to 9.5 million per mission for future projects such as the proposed Mariner Mar 2 series is shown.

  4. Cryptanalysis and improvement of three-particle deterministic secure and high bit-rate direct quantum communication protocol

    NASA Astrophysics Data System (ADS)

    Liu, Zhi-Hao; Chen, Han-Wu; Wang, Dong; Li, Wen-Qian

    2014-06-01

    The three-particle deterministic secure and high bit-rate direct quantum communication protocol and its improved version are analyzed. It shows that an eavesdropper can steal the sender's secret message by the intercept-resend attack and the entanglement attack. The original version is even fragile under denial-of-service attack. As a result, some suggestions to revise them are given.

  5. Communication.

    ERIC Educational Resources Information Center

    Strauss, Andre

    The following essays on communication are presented: communication as a condition of survival, communication for special purposes, the means of transmission of communication, communication within social and economic structures, the teaching of communication through the press, the teaching of modern languages, communication as a point of departure,…

  6. A comparative study of protocols for secure quantum communication under noisy environment: single-qubit-based protocols versus entangled-state-based protocols

    NASA Astrophysics Data System (ADS)

    Sharma, Vishal; Thapliyal, Kishore; Pathak, Anirban; Banerjee, Subhashish

    2016-07-01

    The effect of noise on various protocols of secure quantum communication has been studied. Specifically, we have investigated the effect of amplitude damping, phase damping, squeezed generalized amplitude damping, Pauli type as well as various collective noise models on the protocols of quantum key distribution, quantum key agreement, quantum secure direct quantum communication and quantum dialogue. From each type of protocol of secure quantum communication, we have chosen two protocols for our comparative study: one based on single-qubit states and the other one on entangled states. The comparative study reported here has revealed that single-qubit-based schemes are generally found to perform better in the presence of amplitude damping, phase damping, squeezed generalized amplitude damping noises, while entanglement-based protocols turn out to be preferable in the presence of collective noises. It is also observed that the effect of noise depends upon the number of rounds of quantum communication involved in a scheme of quantum communication. Further, it is observed that squeezing, a completely quantum mechanical resource present in the squeezed generalized amplitude channel, can be used in a beneficial way as it may yield higher fidelity compared to the corresponding zero squeezing case.

  7. Optimal measurements for symmetric quantum states with applications to optical communication

    NASA Astrophysics Data System (ADS)

    Krovi, Hari; Guha, Saikat; Dutton, Zachary; da Silva, Marcus P.

    2015-12-01

    The minimum probability of error (MPE) measurement discriminates between a set of candidate quantum states with the minimum average error probability allowed by quantum mechanics. Conditions for a measurement to be MPE were derived by Yuen, Kennedy, and Lax [H. P. Yuen et al., IEEE Trans. Info. Theory IT-21, 125134 (1975)]. MPE measurements have been found for states that form a single orbit under a group action, i.e., there is a transitive group action on the states in the set. For such state sets, termed geometrically uniform (GU) previously, it was shown that the "pretty good measurement" attains the MPE. Even so, evaluating the actual probability of error (and other performance metrics) attained by the pretty good measurement on a GU set involves inverting large matrices and is not easy in general. Our first contribution is a formula for the MPE and conditional probabilities of GU sets, using group representation theory. Next, we consider sets of pure states that have multiple orbits under the group action. Such states are termed compound geometrically uniform (CGU). MPE measurements for general CGU sets are not known. In this paper, we show how our representation-theoretic description of optimal measurements for GU sets naturally generalizes to the CGU case. We show how to compute the MPE measurement for CGU sets by reducing the problem to solving a few simultaneous equations. The number of equations depends on the sizes of the multiplicity space of irreducible representations. For many common group representations (such as those of several practical good linear codes), this is much more tractable than solving large semidefinite programs—which is what is needed to solve the Yuen-Kennedy-Lax conditions numerically for arbitrary state sets. We show how to evaluate MPE measurements for CGU states in some examples relevant to quantum-limited classical optical communication.

  8. Role of chaos in quantum communication through a dynamical dephasing channel

    NASA Astrophysics Data System (ADS)

    Lemos, Gabriela Barreto; Benenti, Giuliano

    2010-06-01

    In this article we treat the subject of chaotic environments with few degrees of freedom in quantum communication by investigating a conservative dynamical map as a model of a dephasing quantum channel. When the channel’s dynamics is chaotic, we investigate the model’s semi-classical limit and show that the entropy exchange grows at a constant rate which depends on a single parameter (the interaction strength), analogous to stochastic models of dephasing channels. We analyze memory effects in the channel and present strong physical arguments to support that the present model is forgetful in the chaotic regime while memory effects in general cannot be ignored when channel dynamics is regular. In order to render the nonchaotic channel forgetful, it becomes necessary to apply a reset to the channel and this reset can efficiently be modeled by application of a chaotic map. We may then refer to encoding theorems (valid in the case of forgetful channels) to present evidence of a transition from noiseless to noisy channel due to the environment’s transition from regular to chaotic dynamics.

  9. Knowledge About and Perceptions of Advance Care Planning and Communication of Chinese-American Older Adults.

    PubMed

    Yonashiro-Cho, Jeanine; Cote, Sarah; Enguidanos, Susan

    2016-09-01

    Although advance care planning (ACP) is associated with better care at the end of life, better quality of death, and less psychological distress in survivors, ethnic disparities in ACP completion rates have been documented and may be attributable to lack of knowledge about ACP or differences in cultural values and preferences. Despite rapid increases in the size of the Asian-American population, little is known about ACP preferences of Chinese Americans. The purpose of this study is to explore the knowledge, attitudes, and preferences of older Chinese Americans toward ACP. Focus groups with Chinese older adults (n = 34) were conducted in Mandarin, Cantonese, and English, and transcripts were analyzed using a grounded theory approach. Identified themes included knowledge and experience with ACP and end-of-life care options, health as a factor in timing of ACP and communication, and communication of end-of-life care preferences. Knowledge of and experience with ACP and end-of-life decision-making varied according to focus group, although few participants had an advance directive. Findings suggest that Chinese older adults prefer to use indirect communication strategies, such as commenting on the circumstances of others rather than directly stating their wishes, and informal contexts, such as during a family dinner rather than formal meeting, to convey their care preferences to loved ones and may employ similar tactics when communicating with clinicians. This is particularly important given the recent decision by the Centers for Medicare and Medicaid Services to provide reimbursement to physicians for engaging in advance care planning conversations. PMID:27584825

  10. End-of-life communication in Korean older adults: With focus on advance care planning and advance directives.

    PubMed

    Shin, Dong Wook; Lee, Ji Eun; Cho, BeLong; Yoo, Sang Ho; Kim, SangYun; Yoo, Jun-Hyun

    2016-04-01

    The present article aimed to provide a comprehensive review of current status of end-of-life (EOL) care and sociocultural considerations in Korea, with focus on the EOL communication and use of advance directives (AD) in elderly Koreans. Through literature review, we discuss the current status of EOL care and sociocultural considerations in Korea, and provide a look-ahead. In Korea, patients often receive life-sustaining treatment until the very end of life. Advance care planning is rare, and most do-not-resuscitate decisions are made between the family and physician at the very end of patient's life. Koreans, influenced mainly by Confucian tradition, prefer a natural death and discontinuation of life-sustaining treatment. Although Koreans generally believe that death is natural and unavoidable, they tend not to think about or discuss death, and regard preparation for death as unnecessary. As a result, AD are completed by just 4.7% of the general adult population. This situation can be explained by several sociocultural characteristics including opting for natural death, wish not to burden others, preference for family involvement and trust in doctor, avoidance of talking about death, and filial piety. Patients often receive life-sustaining treatment until the very EOL, advance care planning and the use of AD is not common in Korea. This was related to unique sociocultural characteristics of Korea. A more active role of physicians, development of a more deliberate EOL discussion process, development of culturally appropriate AD and promotion of advance care planning might be required to provide good EOL care in Korea.

  11. Clinical skills assessment of procedural and advanced communication skills: performance expectations of residency program directors

    PubMed Central

    Langenau, Erik E.; Zhang, Xiuyuan; Roberts, William L.; DeChamplain, Andre F.; Boulet, John R.

    2012-01-01

    Background High stakes medical licensing programs are planning to augment and adapt current examinations to be relevant for a two-decision point model for licensure: entry into supervised practice and entry into unsupervised practice. Therefore, identifying which skills should be assessed at each decision point is critical for informing examination development, and gathering input from residency program directors is important. Methods Using data from previously developed surveys and expert panels, a web-delivered survey was distributed to 3,443 residency program directors. For each of the 28 procedural and 18 advanced communication skills, program directors were asked which clinical skills should be assessed, by whom, when, and how. Descriptive statistics were collected, and Intraclass Correlations (ICC) were conducted to determine consistency across different specialties. Results Among 347 respondents, program directors reported that all advanced communication and some procedural tasks are important to assess. The following procedures were considered ‘important’ or ‘extremely important’ to assess: sterile technique (93.8%), advanced cardiovascular life support (ACLS) (91.1%), basic life support (BLS) (90.0%), interpretation of electrocardiogram (89.4%) and blood gas (88.7%). Program directors reported that most clinical skills should be assessed at the end of the first year of residency (or later) and not before graduation from medical school. A minority were considered important to assess prior to the start of residency training: demonstration of respectfulness (64%), sterile technique (67.2%), BLS (68.9%), ACLS (65.9%) and phlebotomy (63.5%). Discussion Results from this study support that assessing procedural skills such as cardiac resuscitation, sterile technique, and phlebotomy would be amenable to assessment at the end of medical school, but most procedural and advanced communications skills would be amenable to assessment at the end of the first

  12. Advanced mobile satellite communications system using Ka and MM-wave bands in Japan's R and D satellite project

    NASA Technical Reports Server (NTRS)

    Isobe, Shunkichi; Ohmori, Shingo; Hamamoto, Naokazu; Yamamoto, Minoru

    1991-01-01

    Communications Research Laboratory (CRL) studied an advanced mobile satellite communications system using Ka and millimeter-wave bands in the R&D Satellite project. The project started in 1990 and the satellite will be launched in 1997. On-board multi-beam interconnecting is one of basic functions to realize one-hop connection among Very Small Aperture Terminals (VSATs), mobile, and hand-held terminals in future mobile satellite communications system. An Intermediate Frequency (IF) filter bank and regenerative transponder are suitable for this function. The transponder configuration of an advanced mobile communications mission of the R&D Satellite for experiment is shown. High power transmitters of Ka and millimeter-wave bands, a 3x3 IF filter band and Single Channel Per Carrier/Time Division Multiplexing (SCPC/TDM) regenerative MODEMS, which will be boarded on the R&D Satellite, are being developed for the purpose of studying the feasibility of advanced mobile communications system.

  13. Advances in high-throughput speed, low-latency communication for embedded instrumentation ( 7th Annual SFAF Meeting, 2012)

    ScienceCinema

    Jordan, Scott [Physik Instrumente

    2016-07-12

    Scott Jordan on "Advances in high-throughput speed, low-latency communication for embedded instrumentation" at the 2012 Sequencing, Finishing, Analysis in the Future Meeting held June 5-7, 2012 in Santa Fe, New Mexico.

  14. Advances in high-throughput speed, low-latency communication for embedded instrumentation ( 7th Annual SFAF Meeting, 2012)

    SciTech Connect

    Jordan, Scott

    2012-06-01

    Scott Jordan on "Advances in high-throughput speed, low-latency communication for embedded instrumentation" at the 2012 Sequencing, Finishing, Analysis in the Future Meeting held June 5-7, 2012 in Santa Fe, New Mexico.

  15. A highly reliable, autonomous data communication subsystem for an advanced information processing system

    NASA Technical Reports Server (NTRS)

    Nagle, Gail; Masotto, Thomas; Alger, Linda

    1990-01-01

    The need to meet the stringent performance and reliability requirements of advanced avionics systems has frequently led to implementations which are tailored to a specific application and are therefore difficult to modify or extend. Furthermore, many integrated flight critical systems are input/output intensive. By using a design methodology which customizes the input/output mechanism for each new application, the cost of implementing new systems becomes prohibitively expensive. One solution to this dilemma is to design computer systems and input/output subsystems which are general purpose, but which can be easily configured to support the needs of a specific application. The Advanced Information Processing System (AIPS), currently under development has these characteristics. The design and implementation of the prototype I/O communication system for AIPS is described. AIPS addresses reliability issues related to data communications by the use of reconfigurable I/O networks. When a fault or damage event occurs, communication is restored to functioning parts of the network and the failed or damage components are isolated. Performance issues are addressed by using a parallelized computer architecture which decouples Input/Output (I/O) redundancy management and I/O processing from the computational stream of an application. The autonomous nature of the system derives from the highly automated and independent manner in which I/O transactions are conducted for the application as well as from the fact that the hardware redundancy management is entirely transparent to the application.

  16. Advances in methods and algorithms in a modern quantum chemistry program package.

    PubMed

    Shao, Yihan; Molnar, Laszlo Fusti; Jung, Yousung; Kussmann, Jörg; Ochsenfeld, Christian; Brown, Shawn T; Gilbert, Andrew T B; Slipchenko, Lyudmila V; Levchenko, Sergey V; O'Neill, Darragh P; DiStasio, Robert A; Lochan, Rohini C; Wang, Tao; Beran, Gregory J O; Besley, Nicholas A; Herbert, John M; Lin, Ching Yeh; Van Voorhis, Troy; Chien, Siu Hung; Sodt, Alex; Steele, Ryan P; Rassolov, Vitaly A; Maslen, Paul E; Korambath, Prakashan P; Adamson, Ross D; Austin, Brian; Baker, Jon; Byrd, Edward F C; Dachsel, Holger; Doerksen, Robert J; Dreuw, Andreas; Dunietz, Barry D; Dutoi, Anthony D; Furlani, Thomas R; Gwaltney, Steven R; Heyden, Andreas; Hirata, So; Hsu, Chao-Ping; Kedziora, Gary; Khalliulin, Rustam Z; Klunzinger, Phil; Lee, Aaron M; Lee, Michael S; Liang, Wanzhen; Lotan, Itay; Nair, Nikhil; Peters, Baron; Proynov, Emil I; Pieniazek, Piotr A; Rhee, Young Min; Ritchie, Jim; Rosta, Edina; Sherrill, C David; Simmonett, Andrew C; Subotnik, Joseph E; Woodcock, H Lee; Zhang, Weimin; Bell, Alexis T; Chakraborty, Arup K; Chipman, Daniel M; Keil, Frerich J; Warshel, Arieh; Hehre, Warren J; Schaefer, Henry F; Kong, Jing; Krylov, Anna I; Gill, Peter M W; Head-Gordon, Martin

    2006-07-21

    Advances in theory and algorithms for electronic structure calculations must be incorporated into program packages to enable them to become routinely used by the broader chemical community. This work reviews advances made over the past five years or so that constitute the major improvements contained in a new release of the Q-Chem quantum chemistry package, together with illustrative timings and applications. Specific developments discussed include fast methods for density functional theory calculations, linear scaling evaluation of energies, NMR chemical shifts and electric properties, fast auxiliary basis function methods for correlated energies and gradients, equation-of-motion coupled cluster methods for ground and excited states, geminal wavefunctions, embedding methods and techniques for exploring potential energy surfaces. PMID:16902710

  17. The Impact of the Advancing Social-Communication and Play (ASAP) Intervention on Preschoolers with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Dykstra, Jessica R.; Boyd, Brian A.; Watson, Linda R.; Crais, Elizabeth R.; Baranek, Grace T.

    2012-01-01

    This study evaluates an intervention targeting social-communication and play skills (Advancing Social-communication and Play; ASAP) implemented by school staff in a public preschool setting. With increases in enrollment of children with autism spectrum disorder (ASD) in school systems, establishing the effectiveness and feasibility of…

  18. The Impact of the Advancing Social-Communication and Play (ASAP) Intervention on Preschoolers with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Dykstra, Jessica R.; Boyd, Brian A.; Watson, Linda R.; Crais, Elizabeth R.; Baranek, Grace T.

    2012-01-01

    This study evaluates an intervention targeting social-communication and play skills (Advancing Social-communication And Play; ASAP) implemented by school staff in a public preschool setting. With increases in enrollment of children with autism spectrum disorder (ASD) in school systems, establishing the effectiveness and feasibility of…

  19. Advanced Communication Technology Satellite (ACTS) Very Small Aperture Terminal (VSAT) Network Control Performance

    NASA Technical Reports Server (NTRS)

    Coney, T. A.

    1996-01-01

    This paper discusses the performance of the network control function for the Advanced Communications Technology Satellite (ACTS) very small aperture terminal (VSAT) full mesh network. This includes control of all operational activities such as acquisition, synchronization, timing and rain fade compensation as well as control of all communications activities such as on-demand integrated services (voice, video, and date) connects and disconnects Operations control is provided by an in-band orderwire carried in the baseboard processor (BBP) control burst, the orderwire burst, the reference burst, and the uplink traffic burst. Communication services are provided by demand assigned multiple access (DAMA) protocols. The ACTS implementation of DAMA protocols ensures both on-demand and integrated voice, video and data services. Communications services control is also provided by the in-band orderwire but uses only the reference burst and the uplink traffic burst. The performance of the ACTS network control functions have been successfully tested during on-orbit checkout and in various VSAT networks in day to day operations. This paper discusses the network operations and services control performance.

  20. Advanced driver assistance system for AHS over communication links with random packet dropouts

    NASA Astrophysics Data System (ADS)

    Srinivasan, Seshadhri; Ayyagari, Ramakalyan

    2014-12-01

    In this paper, we propose an advanced driver assist system (ADAS) for platoon based automated highway system (AHS) with packet loss in inter-vehicle communication. Using the concept of rigidity, we first show that vehicles in a platoon tend to fall apart in the event of a packet loss among vehicles. To overcome this, we propose an estimation based dynamic platooning algorithm which employs the state estimate to maintain the platoon. Communication among the vehicle is reduced by using minimum spanning tree (MST) in state estimation algorithm. Effectiveness of the proposed ADAS scheme is illustrated by simulation wherein, dynamic platoons of holonomic vehicles with integrator dynamics are considered. Simulation studies indicate that the proposed algorithm maintains the platoon up to a packet loss rate of 48%. State transmission scheme proposed in our algorithm has three significant advantages, they are: (1) it handles packet loss in inter-vehicle communication, (2) reduces the effect of error in measured output, and (3) reduces the inter-vehicle communication. These advantages significantly increase the reliability and safety of the AHS.

  1. Advances in Ka-Band Communication System for CubeSats and SmallSats

    NASA Technical Reports Server (NTRS)

    Kegege, Obadiah; Wong, Yen F.; Altunc, Serhat

    2016-01-01

    A study was performed that evaluated the feasibility of Ka-band communication system to provide CubeSat/SmallSat high rate science data downlink with ground antennas ranging from the small portable 1.2m/2.4m to apertures 5.4M, 7.3M, 11M, and 18M, for Low Earth Orbit (LEO) to Lunar CubeSat missions. This study included link analysis to determine the data rate requirement, based on the current TRL of Ka-band flight hardware and ground support infrastructure. Recent advances in Ka-band transceivers and antennas, options of portable ground stations, and various coverage distances were included in the analysis. The link/coverage analysis results show that Cubesat/Smallsat missions communication requirements including frequencies and data rates can be met by utilizing Near Earth Network (NEN) Ka-band support with 2 W and high gain (>6 dBi) antennas.

  2. CCSDS Advanced Orbiting Systems - International data communications standards for the Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Hooke, Adrian J.

    1990-01-01

    Established in 1982, the Consultative Committee for Space Data Systems (CCSDS) is an international organization that is staffed by data-handling experts from nearly all of the world's major space agencies. Its goal is to develop standard data-communications techniques so that several agencies may cross-support each other's data flow and thus allow complex, international missions to be flown. Under the general umbrella of Advanced Orbiting Systems (AOS), an international CCSDS task force was formed in 1985 to develop standard data-communications concepts for manned missions, such as the Space Station Freedom and the Hermes space plane, and large unmanned vehicles, such as polar orbiting platforms. The history of the CCSDS and the development of the AOS recommendation are reviewed, and the user services and protocols embodied in its systems architecture are introduced.

  3. Advanced communication satellites worldwide - Satellites of opportunity for the ACTS mobile terminal

    NASA Technical Reports Server (NTRS)

    Girardey, Catherine C.

    1993-01-01

    Space agencies worldwide are involved in advanced satellite communication systems. This paper presents an overview of these satellites and related technologies in the U.S., Europe, and Japan. They are geostationary satellites using high frequency bands such as K/Ka (20/30 GHz) and O-band (millimeter wave), as well as optical frequencies. The similarity of these programs demonstrate a common interest to develop large capacity satellite communication systems, and shows that closer international cooperation could be set up. The ACTS Mobile Terminal (AMT) project discussed here is such an example. The AMT's compatibility with satellites other than ACTS has been studied, and a proposed common experiment is presented here. The Japanese Engineering Test Satellite ETS-VI has been identified as the best initial 'satellite of opportunity' for AMT in this preliminary assessment.

  4. Advanced digital modulation: Communication techniques and monolithic GaAs technology

    NASA Technical Reports Server (NTRS)

    Wilson, S. G.; Oliver, J. D., Jr.; Kot, R. C.; Richards, C. R.

    1983-01-01

    Communications theory and practice are merged with state-of-the-art technology in IC fabrication, especially monolithic GaAs technology, to examine the general feasibility of a number of advanced technology digital transmission systems. Satellite-channel models with (1) superior throughput, perhaps 2 Gbps; (2) attractive weight and cost; and (3) high RF power and spectrum efficiency are discussed. Transmission techniques possessing reasonably simple architectures capable of monolithic fabrication at high speeds were surveyed. This included a review of amplitude/phase shift keying (APSK) techniques and the continuous-phase-modulation (CPM) methods, of which MSK represents the simplest case.

  5. ACTS (Advanced Communications Technology Satellite) Propagation Experiment: Preprocessing Software User's Manual

    NASA Technical Reports Server (NTRS)

    Crane, Robert K.; Wang, Xuhe; Westenhaver, David

    1996-01-01

    The preprocessing software manual describes the Actspp program originally developed to observe and diagnose Advanced Communications Technology Satellite (ACTS) propagation terminal/receiver problems. However, it has been quite useful for automating the preprocessing functions needed to convert the terminal output to useful attenuation estimates. Prior to having data acceptable for archival functions, the individual receiver system must be calibrated and the power level shifts caused by ranging tone modulation must be received. Actspp provides three output files: the daylog, the diurnal coefficient file, and the file that contains calibration information.

  6. High-speed image transmission via the Advanced Communication Technology Satellite (ACTS)

    NASA Astrophysics Data System (ADS)

    Bazzill, Todd M.; Huang, H. K.; Thoma, George R.; Long, L. Rodney; Gill, Michael J.

    1996-05-01

    We are developing a wide area test bed network using the Advanced Communication Technology Satellite (ACTS) from NASA for high speed medical image transmission. The two test sites are the University of California, San Francisco, and the National Library of Medicine. The first phase of the test bed runs over a T1 link (1.544 Mbits/sec) using a Very Small Aperture Terminal. The second phase involves the High Data Rate Terminal via an ATM OC 3C (155 Mbits/sec) connection. This paper describes the experimental set up and some preliminary results from phase 1.

  7. Realization of quantum digital signatures without the requirement of quantum memory.

    PubMed

    Collins, Robert J; Donaldson, Ross J; Dunjko, Vedran; Wallden, Petros; Clarke, Patrick J; Andersson, Erika; Jeffers, John; Buller, Gerald S

    2014-07-25

    Digital signatures are widely used to provide security for electronic communications, for example, in financial transactions and electronic mail. Currently used classical digital signature schemes, however, only offer security relying on unproven computational assumptions. In contrast, quantum digital signatures offer information-theoretic security based on laws of quantum mechanics. Here, security against forging relies on the impossibility of perfectly distinguishing between nonorthogonal quantum states. A serious drawback of previous quantum digital signature schemes is that they require long-term quantum memory, making them impractical at present. We present the first realization of a scheme that does not need quantum memory and which also uses only standard linear optical components and photodetectors. In our realization, the recipients measure the distributed quantum signature states using a new type of quantum measurement, quantum state elimination. This significantly advances quantum digital signatures as a quantum technology with potential for real applications. PMID:25105603

  8. Realization of Quantum Digital Signatures without the Requirement of Quantum Memory

    NASA Astrophysics Data System (ADS)

    Collins, Robert J.; Donaldson, Ross J.; Dunjko, Vedran; Wallden, Petros; Clarke, Patrick J.; Andersson, Erika; Jeffers, John; Buller, Gerald S.

    2014-07-01

    Digital signatures are widely used to provide security for electronic communications, for example, in financial transactions and electronic mail. Currently used classical digital signature schemes, however, only offer security relying on unproven computational assumptions. In contrast, quantum digital signatures offer information-theoretic security based on laws of quantum mechanics. Here, security against forging relies on the impossibility of perfectly distinguishing between nonorthogonal quantum states. A serious drawback of previous quantum digital signature schemes is that they require long-term quantum memory, making them impractical at present. We present the first realization of a scheme that does not need quantum memory and which also uses only standard linear optical components and photodetectors. In our realization, the recipients measure the distributed quantum signature states using a new type of quantum measurement, quantum state elimination. This significantly advances quantum digital signatures as a quantum technology with potential for real applications.

  9. Enhancing Extemporaneous Speaking Skills in the Advanced Oral Communication Course and Team Testing Techniques in the Basic Course.

    ERIC Educational Resources Information Center

    Reppert, James E.

    In an advanced oral communication course, students make five major presentations. One of the foundations of extemporaneous speaking is the ability to outline relevant points and phrases in a coherent, orderly manner. Advanced students must be able to take any topic and dissect it quickly to determine the most succinct way to present it to an…

  10. Faithful deterministic secure quantum communication and authentication protocol based on hyperentanglement against collective noise

    NASA Astrophysics Data System (ADS)

    Chang, Yan; Zhang, Shi-Bin; Yan, Li-Li; Han, Gui-Hua

    2015-08-01

    Higher channel capacity and security are difficult to reach in a noisy channel. The loss of photons and the distortion of the qubit state are caused by noise. To solve these problems, in our study, a hyperentangled Bell state is used to design faithful deterministic secure quantum communication and authentication protocol over collective-rotation and collective-dephasing noisy channel, which doubles the channel capacity compared with using an ordinary Bell state as a carrier; a logical hyperentangled Bell state immune to collective-rotation and collective-dephasing noise is constructed. The secret message is divided into several parts to transmit, however the identity strings of Alice and Bob are reused. Unitary operations are not used. Project supported by the National Natural Science Foundation of China (Grant No. 61402058), the Science and Technology Support Project of Sichuan Province, China (Grant No. 2013GZX0137), the Fund for Young Persons Project of Sichuan Province, China (Grant No. 12ZB017), and the Foundation of Cyberspace Security Key Laboratory of Sichuan Higher Education Institutions, China (Grant No. szjj2014-074).

  11. Monolithically integrated quantum dot optical modulator with Semiconductor optical amplifier for short-range optical communications

    NASA Astrophysics Data System (ADS)

    Yamamoto, Naokatsu; Akahane, Kouichi; Umezawa, Toshimasa; Kawanishi, Tetsuya

    2015-04-01

    A monolithically integrated quantum dot (QD) optical gain modulator (OGM) with a QD semiconductor optical amplifier (SOA) was successfully developed. Broadband QD optical gain material was used to achieve Gbps-order high-speed optical data transmission, and an optical gain change as high as approximately 6-7 dB was obtained with a low OGM voltage of 2.0 V. Loss of optical power due to insertion of the device was also effectively compensated for by the SOA section. Furthermore, it was confirmed that the QD-OGM/SOA device helped achieve 6.0-Gbps error-free optical data transmission over a 2.0-km-long photonic crystal fiber. We also successfully demonstrated generation of Gbps-order, high-speed, and error-free optical signals in the >5.5-THz broadband optical frequency bandwidth larger than the C-band. These results suggest that the developed monolithically integrated QD-OGM/SOA device will be an advantageous and compact means of increasing the usable optical frequency channels for short-reach communications.

  12. Advance Directives and Communication Skills of Prehospital Physicians Involved in the Care of Cardiovascular Patients.

    PubMed

    Gigon, Fabienne; Merlani, Paolo; Ricou, Bara

    2015-12-01

    Advance directives (AD) were developed to respect patient autonomy. However, very few patients have AD, even in cases when major cardiovascular surgery is to follow. To understand the reasons behind the low prevalence of AD and to help decision making when patients are incompetent, it is necessary to focus on the impact of prehospital practitioners, who may contribute to an increase in AD by discussing them with patients. The purpose of this study was to investigate self-rated communication skills and the attitudes of physicians potentially involved in the care of cardiovascular patients toward AD.Self-administered questionnaires were sent to general practitioners, cardiologists, internists, and intensivists, including the Quality of Communication Score, divided into a General Communication score (QOCgen 6 items) and an End-of-life Communication score (QOCeol 7 items), as well as questions regarding opinions and practices in terms of AD.One hundred sixty-four responses were received. QOCgen (mean (±SD)): 9.0/10 (1.0); QOCeol: 7.2/10 (1.7). General practitioners most frequently start discussions about AD (74/149 [47%]) and are more prone to designate their own specialty (30/49 [61%], P < 0.0001). Overall, only 57/159 (36%) physicians designated their own specialty; 130/158 (82%) physicians ask potential cardiovascular patients if they have AD and 61/118 (52%) physicians who care for cardiovascular patients talk about AD with some of them.The characteristics of physicians who do not talk about AD with patients were those who did not personally have AD and those who work in private practices.One hundred thirty-three (83%) physicians rated the systematic mention of patients' AD in the correspondence between physicians as good, while 114 (71%) at the patients' first registration in the private practice.Prehospital physicians rated their communication skills as good, whereas end-of-life communication was rated much lower. Only half of those surveyed speak about AD

  13. Erratum "New arbitrated quantum signature of classical messages against collective amplitude damping noise" [Optics Communications 284 (2011) 3144

    NASA Astrophysics Data System (ADS)

    Luo, Yi-Ping; Hwang, Tzonelih

    2013-08-01

    We point out that our previous work [Optics Communications 284 (2011) 3144] contains a mistake in the key updating equation. We correct the error to avoid an information leakage problem. We revisit our previous work entitled "New arbitrated quantum signature of classical messages against collective amplitude damping noise" [1] and discover a mistake in the key updating equation which could cause a key to reveal to a semi-honest arbitrator.

  14. Quantum dot semiconductor optical amplifier/silicon external cavity laser for O-band high-speed optical communications

    NASA Astrophysics Data System (ADS)

    Yang, Shuyu; Zhang, Yi; Li, Qi; Zhu, Xiaoliang; Bergman, Keren; Magill, Peter; Baehr-Jones, Thomas; Hochberg, Michael

    2015-02-01

    We report a hybrid integrated external cavity laser by butt coupling a quantum dot reflective semiconductor optical amplifier and a silicon-on-insulator chip. The device lasers at 1302 nm in the O-band, a wavelength regime critical to data communication systems. We measured 18 mW on-chip output power and over 50-dB side-mode suppression ratio. We also demonstrated open eye diagrams at 10 and 40 Gb/s.

  15. An advanced Ka band phased array communication system at commercial frequencies

    NASA Astrophysics Data System (ADS)

    Wald, Lawrence; Kacpura, Thomas; Kershner, Dennis

    2000-01-01

    The Glenn Research Center (GRC) Direct Data Distribution (D3) project will demonstrate an advanced, high-performance communication system that transmits information from a technology payload carried by the Space Shuttle in low-Earth orbit (LEO) to a small receiving terminal on the Earth. The Shuttle-based communications package will utilize a solid-state, Ka-band phased array antenna that electronically steers the 19.05 Ghz RF signal toward a low-cost, tracking ground terminal, thereby providing agile, vibration-free, electronic steering at reduced size and weight with increased reliability. The project will also demonstrate new digital modulation and processing technology that will allow transmission of user/platform data at rates up to 1200 Mbits per second. This capability will enable the management of the substantially increased amounts of data to be collected from the International Space Station (ISS) or other LEO platforms directly to NASA field centers, principal investigators, or into the commercial terrestrial communications network. .

  16. Gauge-fields and integrated quantum-classical theory

    SciTech Connect

    Stapp, H.P.

    1986-01-01

    Physical situations in which quantum systems communicate continuously to their classically described environment are not covered by contemporary quantum theory, which requires a temporary separation of quantum degrees of freedom from classical ones. A generalization would be needed to cover these situations. An incomplete proposal is advanced for combining the quantum and classical degrees of freedom into a unified objective description. It is based on the use of certain quantum-classical structures of light that arise from gauge invariance to coordinate the quantum and classical degrees of freedom. Also discussed is the question of where experimenters should look to find phenomena pertaining to the quantum-classical connection. 17 refs.

  17. Implementing a quantum cloning machine in separate cavities via the optical coherent pulse as a quantum communication bus

    NASA Astrophysics Data System (ADS)

    Zhu, Meng-Zheng; Ye, Liu

    2015-04-01

    An efficient scheme is proposed to implement a quantum cloning machine in separate cavities based on a hybrid interaction between electron-spin systems placed in the cavities and an optical coherent pulse. The coefficient of the output state for the present cloning machine is just the direct product of two trigonometric functions, which ensures that different types of quantum cloning machine can be achieved readily in the same framework by appropriately adjusting the rotated angles. The present scheme can implement optimal one-to-two symmetric (asymmetric) universal quantum cloning, optimal symmetric (asymmetric) phase-covariant cloning, optimal symmetric (asymmetric) real-state cloning, optimal one-to-three symmetric economical real-state cloning, and optimal symmetric cloning of qubits given by an arbitrary axisymmetric distribution. In addition, photon loss of the qubus beams during the transmission and decoherence effects caused by such a photon loss are investigated.

  18. Antennas Designed for Advanced Communications for Air Traffic Management (AC/ATM) Project

    NASA Technical Reports Server (NTRS)

    Zakrajsek, Robert J.

    2000-01-01

    The goal of the Advanced Communications for Air Traffic Management (AC/ATM) Project at the NASA Glenn Research Center at Lewis Field is to enable a communications infrastructure that provides the capacity, efficiency, and flexibility necessary to realize a mature free-flight environment. The technical thrust of the AC/ATM Project is targeted at the design, development, integration, test, and demonstration of enabling technologies for global broadband aeronautical communications. Since Ku-band facilities and equipment are readily available, one of the near-term demonstrations involves a link through a Kuband communications satellite. Two conformally mounted antennas will support the initial AC/ATM communications links. Both of these are steered electronically through monolithic microwave integrated circuit (MMIC) amplifiers and phase shifters. This link will be asymmetrical with the downlink to the aircraft (mobile vehicle) at a throughput rate of greater than 1.5 megabits per second (Mbps), whereas the throughput rate of the uplink from the aircraft will be greater than 100 kilobits per second (kbps). The data on the downlink can be narrow-band, wide-band, or a combination of both, depending on the requirements of the experiment. The AC/ATM project is purchasing a phased-array Ku-band transmitting antenna for the uplink from the test vehicle. Many Ku-band receiving antennas have been built, and one will be borrowed for a short time to perform the initial experiments at the NASA Glenn Research Center at Lewis Field. The Ku-band transmitting antenna is a 254-element MMIC phased-array antenna being built by Boeing Phantom Works. Each element can radiate 100 mW. The antenna is approximately 43-cm high by 24-cm wide by 3.3-cm thick. It can be steered beyond 60 from broadside. The beamwidth varies from 6 at broadside to 12 degrees at 60 degrees, which is typical of phased-array antennas. When the antenna is steered to 60 degrees, the beamwidth will illuminate

  19. Quantum Mechanics

    NASA Astrophysics Data System (ADS)

    Auletta, Gennaro; Fortunato, Mauro; Parisi, Giorgio

    2014-01-01

    Introduction; Part I. Basic Features of Quantum Mechanics: 1. From classical mechanics to quantum mechanics; 2. Quantum observable and states; 3. Quantum dynamics; 4. Examples of quantum dynamics; 5. Density matrix; Part II. More Advanced Topics: 6. Angular momentum and spin; 7. Identical particles; 8. Symmetries and conservation laws; 9. The measurement problem; Part III. Matter and Light: 10. Perturbations and approximation methods; 11. Hydrogen and helium atoms; 12. Hydrogen molecular ion; 13. Quantum optics; Part IV. Quantum Information: State and Correlations: 14. Quantum theory of open systems; 15. State measurement in quantum mechanics; 16. Entanglement: non-separability; 17. Entanglement: quantum information; References; Index.

  20. Nonlocality and communication complexity

    NASA Astrophysics Data System (ADS)

    Buhrman, Harry; Cleve, Richard; Massar, Serge; de Wolf, Ronald

    2010-01-01

    Quantum information processing is the emerging field that defines and realizes computing devices that make use of quantum mechanical principles such as the superposition principle, entanglement, and interference. Until recently the common notion of computing was based on classical mechanics and did not take into account all the possibilities that physically realizable computing devices offer in principle. The field gained momentum after Shor developed an efficient algorithm for factoring numbers, demonstrating the potential computing powers that quantum computing devices can unleash. In this review the information counterpart of computing is studied. It was realized early on by Holevo that quantum bits, the quantum mechanical counterpart of classical bits, cannot be used for efficient transformation of information in the sense that arbitrary k -bit messages cannot be compressed into messages of k-1 qubits. The abstract form of the distributed computing setting is called communication complexity. It studies the amount of information, in terms of bits or in our case qubits, that two spatially separated computing devices need to exchange in order to perform some computational task. Surprisingly, quantum mechanics can be used to obtain dramatic advantages for such tasks. The area of quantum communication complexity is reviewed and it is shown how it connects the foundational physics questions regarding nonlocality with those of communication complexity studied in theoretical computer science. The first examples exhibiting the advantage of the use of qubits in distributed information-processing tasks were based on nonlocality tests. However, by now the field has produced strong and interesting quantum protocols and algorithms of its own that demonstrate that entanglement, although it cannot be used to replace communication, can be used to reduce the communication exponentially. In turn, these new advances yield a new outlook on the foundations of physics and could even

  1. The Integrated Safety-Critical Advanced Avionics Communication and Control (ISAACC) System Concept: Infrastructure for ISHM

    NASA Technical Reports Server (NTRS)

    Gwaltney, David A.; Briscoe, Jeri M.

    2005-01-01

    Integrated System Health Management (ISHM) architectures for spacecraft will include hard real-time, critical subsystems and soft real-time monitoring subsystems. Interaction between these subsystems will be necessary and an architecture supporting multiple criticality levels will be required. Demonstration hardware for the Integrated Safety-Critical Advanced Avionics Communication & Control (ISAACC) system has been developed at NASA Marshall Space Flight Center. It is a modular system using a commercially available time-triggered protocol, ?Tp/C, that supports hard real-time distributed control systems independent of the data transmission medium. The protocol is implemented in hardware and provides guaranteed low-latency messaging with inherent fault-tolerance and fault-containment. Interoperability between modules and systems of modules using the TTP/C is guaranteed through definition of messages and the precise message schedule implemented by the master-less Time Division Multiple Access (TDMA) communications protocol. "Plug-and-play" capability for sensors and actuators provides automatically configurable modules supporting sensor recalibration and control algorithm re-tuning without software modification. Modular components of controlled physical system(s) critical to control algorithm tuning, such as pumps or valve components in an engine, can be replaced or upgraded as "plug and play" components without modification to the ISAACC module hardware or software. ISAACC modules can communicate with other vehicle subsystems through time-triggered protocols or other communications protocols implemented over Ethernet, MIL-STD- 1553 and RS-485/422. Other communication bus physical layers and protocols can be included as required. In this way, the ISAACC modules can be part of a system-of-systems in a vehicle with multi-tier subsystems of varying criticality. The goal of the ISAACC architecture development is control and monitoring of safety critical systems of a

  2. An experiment in remote manufacturing using the advanced communications technology satellite

    NASA Technical Reports Server (NTRS)

    Tsatsoulis, Costas; Frost, Victor

    1991-01-01

    The goal of the completed project was to develop an experiment in remote manufacturing that would use the capabilities of the ACTS satellite. A set of possible experiments that could be performed using the Advanced Communications Technology Satellite (ACTS), and which would perform remote manufacturing using a laser cutter and an integrated circuit testing machine are described in detail. The proposed design is shown to be a feasible solution to the offered problem and it takes into consideration the constraints that were placed on the experiment. In addition, we have developed two more experiments that are included in this report: backup of rural telecommunication networks, and remote use of Synthetic Aperture Radar (SAR) data analysis for on-site collection of glacier scattering data in the Antarctic.

  3. Design and Development of a Baseband Processor for the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Lee, Kerry D.

    1996-01-01

    This paper describes the implementation of the operational baseband processor (BBP) subsystem on board the NASA Advanced Communications Technology Satellite (ACTS). The BBP supports the network consisting of the NASA ground station (NGS) low burst rate (LBR) terminals, and the T1 very small aperture terminals (VSAT's), to provide flexible, demand assigned satellite switched (SS), baseband processed frequency division modulated (FDM)/time division multiple access (TDMA) operations. This paper presents an overview of the baseband processor and includes a description of the data flow, functional block diagrams, and a discussion of the implementation of BBP. A discussion of the supporting technologies for the BBP is presented. A brief summary of BBP-level performance testing is also presented. Finally, a discussion of the implications of current technology on the BBP design, if it were to be developed today, is presented.

  4. An experiment in remote manufacturing using the advanced communications technology satellite

    NASA Astrophysics Data System (ADS)

    Tsatsoulis, Costas; Frost, Victor

    1991-10-01

    The goal of the completed project was to develop an experiment in remote manufacturing that would use the capabilities of the ACTS satellite. A set of possible experiments that could be performed using the Advanced Communications Technology Satellite (ACTS), and which would perform remote manufacturing using a laser cutter and an integrated circuit testing machine are described in detail. The proposed design is shown to be a feasible solution to the offered problem and it takes into consideration the constraints that were placed on the experiment. In addition, we have developed two more experiments that are included in this report: backup of rural telecommunication networks, and remote use of Synthetic Aperture Radar (SAR) data analysis for on-site collection of glacier scattering data in the Antarctic.

  5. Globalization and advances in information and communication technologies: the impact on nursing and health.

    PubMed

    Abbott, Patricia A; Coenen, Amy

    2008-01-01

    Globalization and information and communication technology (ICT) continue to change us and the world we live in. Nursing stands at an opportunity intersection where challenging global health issues, an international workforce shortage, and massive growth of ICT combine to create a very unique space for nursing leadership and nursing intervention. Learning from prior successes in the field can assist nurse leaders in planning and advancing strategies for global health using ICT. Attention to lessons learned will assist in combating the technological apartheid that is already present in many areas of the globe and will highlight opportunities for innovative applications in health. ICT has opened new channels of communication, creating the beginnings of a global information society that will facilitate access to isolated areas where health needs are extreme and where nursing can contribute significantly to the achievement of "Health for All." The purpose of this article is to discuss the relationships between globalization, health, and ICT, and to illuminate opportunities for nursing in this flattening and increasingly interconnected world. PMID:18922277

  6. Dynamic rain fade compensation techniques for the advanced communications technology satellite

    NASA Technical Reports Server (NTRS)

    Manning, Robert M.

    1992-01-01

    The dynamic and composite nature of propagation impairments that are incurred on earth-space communications links at frequencies in and above the 30/20 GHz Ka band necessitate the use of dynamic statistical identification and prediction processing of the fading signal in order to optimally estimate and predict the levels of each of the deleterious attenuation components. Such requirements are being met in NASA's Advanced Communications Technology Satellite (ACTS) project by the implementation of optimal processing schemes derived through the use of the ACTS Rain Attenuation Prediction Model and nonlinear Markov filtering theory. The ACTS Rain Attenuation Prediction Model discerns climatological variations on the order of 0.5 deg in latitude and longitude in the continental U.S. The time-dependent portion of the model gives precise availability predictions for the 'spot beam' links of ACTS. However, the structure of the dynamic portion of the model, which yields performance parameters such as fade duration probabilities, is isomorphic to the state-variable approach of stochastic control theory and is amenable to the design of such statistical fade processing schemes which can be made specific to the particular climatological location at which they are employed.

  7. The link evaluation terminal for the advanced communications technology satellite experiments program

    NASA Technical Reports Server (NTRS)

    May, Brian D.

    1992-01-01

    The experimental NASA satellite, Advanced Communications Technology Satellite (ACTS), introduces new technology for high throughput 30 to 20 GHz satellite services. Contained in a single communication payload is both a regenerative TDMA system and multiple 800 MHz 'bent pipe' channels routed to spot beams by a switch matrix. While only one mode of operation is typical during any experiment, both modes can operate simultaneously with reduced capability due to sharing of the transponder. NASA-Lewis instituted a ground terminal development program in anticipation of the satellite launch to verify the performance of the switch matrix mode of operations. Specific functions are built into the ground terminal to evaluate rain fade compensation with uplink power control and to monitor satellite transponder performance with bit error rate measurements. These functions were the genesis of the ground terminal's name, Link Evaluation Terminal, often referred to as LET. Connectors are included in LET that allow independent experimenters to run unique modulation or network experiments through ACTS using only the RF transmit and receive portions of LET. Test data indicate that LET will be able to verify important parts of ACTS technology and provide independent experimenters with a useful ground terminal. Lab measurements of major subsystems integrated into LET are presented. Bit error rate is measured with LET in an internal loopback mode.

  8. The Link Evaluation Terminal for the Advanced Communications Technology Satellite Experiments Program

    NASA Technical Reports Server (NTRS)

    May, Brian D.

    1992-01-01

    The experimental NASA satellite, Advanced Communications Technology Satellite (ACTS), introduces new technology for high throughput 30 to 20 GHz satellite services. Contained in a single communication payload is both a regenerative TDMA system and multiple 800 MHz 'bent pipe' channels routed to spot beams by a switch matrix. While only one mode of operation is typical during any experiment, both modes can operate simultaneously with reduced capability due to sharing of the transponder. NASA-Lewis instituted a ground terminal development program in anticipation of the satellite launch to verify the performance of the switch matrix mode of operations. Specific functions are built into the ground terminal to evaluate rain fade compensation with uplink power control and to monitor satellite transponder performance with bit error rate measurements. These functions were the genesis of the ground terminal's name, Link Evaluation Terminal, often referred to as LET. Connectors are included in LET that allow independent experimenters to run unique modulation or network experiments through ACTS using only the RF transmit and receive portions of LET. Test data indicate that LET will be able to verify important parts of ACTS technology and provide independent experimenters with a useful ground terminal. Lab measurements of major subsystems integrated into LET are presented. Bit error rate is measured with LET in an internal loopback mode.

  9. High security chaotic multiple access scheme for visible light communication systems with advanced encryption standard interleaving

    NASA Astrophysics Data System (ADS)

    Qiu, Junchao; Zhang, Lin; Li, Diyang; Liu, Xingcheng

    2016-06-01

    Chaotic sequences can be applied to realize multiple user access and improve the system security for a visible light communication (VLC) system. However, since the map patterns of chaotic sequences are usually well known, eavesdroppers can possibly derive the key parameters of chaotic sequences and subsequently retrieve the information. We design an advanced encryption standard (AES) interleaving aided multiple user access scheme to enhance the security of a chaotic code division multiple access-based visible light communication (C-CDMA-VLC) system. We propose to spread the information with chaotic sequences, and then the spread information is interleaved by an AES algorithm and transmitted over VLC channels. Since the computation complexity of performing inverse operations to deinterleave the information is high, the eavesdroppers in a high speed VLC system cannot retrieve the information in real time; thus, the system security will be enhanced. Moreover, we build a mathematical model for the AES-aided VLC system and derive the theoretical information leakage to analyze the system security. The simulations are performed over VLC channels, and the results demonstrate the effectiveness and high security of our presented AES interleaving aided chaotic CDMA-VLC system.

  10. Quantum information processing with atoms and photons.

    PubMed

    Monroe, C

    2002-03-14

    Quantum information processors exploit the quantum features of superposition and entanglement for applications not possible in classical devices, offering the potential for significant improvements in the communication and processing of information. Experimental realization of large-scale quantum information processors remains a long-term vision, as the required nearly pure quantum behaviour is observed only in exotic hardware such as individual laser-cooled atoms and isolated photons. But recent theoretical and experimental advances suggest that cold atoms and individual photons may lead the way towards bigger and better quantum information processors, effectively building mesoscopic versions of 'Schrödinger's cat' from the bottom up.

  11. Relativistic Quantum Metrology: Exploiting relativity to improve quantum measurement technologies

    PubMed Central

    Ahmadi, Mehdi; Bruschi, David Edward; Sabín, Carlos; Adesso, Gerardo; Fuentes, Ivette

    2014-01-01

    We present a framework for relativistic quantum metrology that is useful for both Earth-based and space-based technologies. Quantum metrology has been so far successfully applied to design precision instruments such as clocks and sensors which outperform classical devices by exploiting quantum properties. There are advanced plans to implement these and other quantum technologies in space, for instance Space-QUEST and Space Optical Clock projects intend to implement quantum communications and quantum clocks at regimes where relativity starts to kick in. However, typical setups do not take into account the effects of relativity on quantum properties. To include and exploit these effects, we introduce techniques for the application of metrology to quantum field theory. Quantum field theory properly incorporates quantum theory and relativity, in particular, at regimes where space-based experiments take place. This framework allows for high precision estimation of parameters that appear in quantum field theory including proper times and accelerations. Indeed, the techniques can be applied to develop a novel generation of relativistic quantum technologies for gravimeters, clocks and sensors. As an example, we present a high precision device which in principle improves the state-of-the-art in quantum accelerometers by exploiting relativistic effects. PMID:24851858

  12. Relativistic quantum metrology: exploiting relativity to improve quantum measurement technologies.

    PubMed

    Ahmadi, Mehdi; Bruschi, David Edward; Sabín, Carlos; Adesso, Gerardo; Fuentes, Ivette

    2014-05-22

    We present a framework for relativistic quantum metrology that is useful for both Earth-based and space-based technologies. Quantum metrology has been so far successfully applied to design precision instruments such as clocks and sensors which outperform classical devices by exploiting quantum properties. There are advanced plans to implement these and other quantum technologies in space, for instance Space-QUEST and Space Optical Clock projects intend to implement quantum communications and quantum clocks at regimes where relativity starts to kick in. However, typical setups do not take into account the effects of relativity on quantum properties. To include and exploit these effects, we introduce techniques for the application of metrology to quantum field theory. Quantum field theory properly incorporates quantum theory and relativity, in particular, at regimes where space-based experiments take place. This framework allows for high precision estimation of parameters that appear in quantum field theory including proper times and accelerations. Indeed, the techniques can be applied to develop a novel generation of relativistic quantum technologies for gravimeters, clocks and sensors. As an example, we present a high precision device which in principle improves the state-of-the-art in quantum accelerometers by exploiting relativistic effects.

  13. Relativistic quantum metrology: exploiting relativity to improve quantum measurement technologies.

    PubMed

    Ahmadi, Mehdi; Bruschi, David Edward; Sabín, Carlos; Adesso, Gerardo; Fuentes, Ivette

    2014-01-01

    We present a framework for relativistic quantum metrology that is useful for both Earth-based and space-based technologies. Quantum metrology has been so far successfully applied to design precision instruments such as clocks and sensors which outperform classical devices by exploiting quantum properties. There are advanced plans to implement these and other quantum technologies in space, for instance Space-QUEST and Space Optical Clock projects intend to implement quantum communications and quantum clocks at regimes where relativity starts to kick in. However, typical setups do not take into account the effects of relativity on quantum properties. To include and exploit these effects, we introduce techniques for the application of metrology to quantum field theory. Quantum field theory properly incorporates quantum theory and relativity, in particular, at regimes where space-based experiments take place. This framework allows for high precision estimation of parameters that appear in quantum field theory including proper times and accelerations. Indeed, the techniques can be applied to develop a novel generation of relativistic quantum technologies for gravimeters, clocks and sensors. As an example, we present a high precision device which in principle improves the state-of-the-art in quantum accelerometers by exploiting relativistic effects. PMID:24851858

  14. Realization of reliable solid-state quantum memory for photonic polarization qubit.

    PubMed

    Zhou, Zong-Quan; Lin, Wei-Bin; Yang, Ming; Li, Chuan-Feng; Guo, Guang-Can

    2012-05-11

    Faithfully storing an unknown quantum light state is essential to advanced quantum communication and distributed quantum computation applications. The required quantum memory must have high fidelity to improve the performance of a quantum network. Here we report the reversible transfer of photonic polarization states into collective atomic excitation in a compact solid-state device. The quantum memory is based on an atomic frequency comb (AFC) in rare-earth ion-doped crystals. We obtain up to 0.999 process fidelity for the storage and retrieval process of single-photon-level coherent pulse. This reliable quantum memory is a crucial step toward quantum networks based on solid-state devices.

  15. Three-party Quantum Secure Direct Communication with Single Photons in both Polarization and Spatial-mode Degrees of Freedom

    NASA Astrophysics Data System (ADS)

    Wang, LiLi; Ma, WenPing; Wang, MeiLing; Shen, DongSu

    2016-05-01

    We present an efficient three-party quantum secure direct communication (QSDC) protocol with single photos in both polarization and spatial-mode degrees of freedom. The three legal parties' messages can be encoded on the polarization and the spatial-mode states of single photons independently with desired unitary operations. A party can obtain the other two parties' messages simultaneously through a quantum channel. Because no extra public information is transmitted in the classical channels, the drawback of information leakage or classical correlation does not exist in the proposed scheme. Moreover, the comprehensive security analysis shows that the presented QSDC network protocol can defend the outsider eavesdropper's several sorts of attacks. Compared with the single photons with only one degree of freedom, our protocol based on the single photons in two degrees of freedom has higher capacity. Since the preparation and the measurement of single photon quantum states in both the polarization and the spatial-mode degrees of freedom are available with current quantum techniques, the proposed protocol is practical.

  16. Open-loop quantum control as a resource for secure communications

    NASA Astrophysics Data System (ADS)

    Pastorello, Davide

    2016-05-01

    Properties of unitary time evolution of quantum systems can be applied to define quantum cryptographic protocols. Dynamics of a qubit can be exploited as a data encryption/decryption procedure by means of timed measurements, implementation of an open-loop control scheme over a qubit increases robustness of a protocol employing this principle.

  17. Recent advances toward a general purpose linear-scaling quantum force field.

    PubMed

    Giese, Timothy J; Huang, Ming; Chen, Haoyuan; York, Darrin M

    2014-09-16

    Conspectus There is need in the molecular simulation community to develop new quantum mechanical (QM) methods that can be routinely applied to the simulation of large molecular systems in complex, heterogeneous condensed phase environments. Although conventional methods, such as the hybrid quantum mechanical/molecular mechanical (QM/MM) method, are adequate for many problems, there remain other applications that demand a fully quantum mechanical approach. QM methods are generally required in applications that involve changes in electronic structure, such as when chemical bond formation or cleavage occurs, when molecules respond to one another through polarization or charge transfer, or when matter interacts with electromagnetic fields. A full QM treatment, rather than QM/MM, is necessary when these features present themselves over a wide spatial range that, in some cases, may span the entire system. Specific examples include the study of catalytic events that involve delocalized changes in chemical bonds, charge transfer, or extensive polarization of the macromolecular environment; drug discovery applications, where the wide range of nonstandard residues and protonation states are challenging to model with purely empirical MM force fields; and the interpretation of spectroscopic observables. Unfortunately, the enormous computational cost of conventional QM methods limit their practical application to small systems. Linear-scaling electronic structure methods (LSQMs) make possible the calculation of large systems but are still too computationally intensive to be applied with the degree of configurational sampling often required to make meaningful comparison with experiment. In this work, we present advances in the development of a quantum mechanical force field (QMFF) suitable for application to biological macromolecules and condensed phase simulations. QMFFs leverage the benefits provided by the LSQM and QM/MM approaches to produce a fully QM method that is able to

  18. Renewable Energy SCADA/Training Using NASA's Advanced Technology Communication Satellite

    NASA Technical Reports Server (NTRS)

    Kalu, A.; Emrich, C.; Ventre, G.; Wilson, W.; Acosta, Roberto (Technical Monitor)

    2000-01-01

    The lack of electrical energy in the rural communities of developing countries is well known, as is the economic unfeasibility of providing much needed energy to these regions via electric grids. Renewable energy (RE) can provide an economic advantage over conventional forms in meeting some of these energy needs. The use of a Supervisory Control and Data Acquisition (SCADA) arrangement via satellite could enable experts at remote locations to provide technical assistance to local trainees while they acquire a measure of proficiency with a newly installed RE system through hands-on training programs using the same communications link. Upon full mastery of the technologies, indigenous personnel could also employ similar SCADA arrangements to remotely monitor and control their constellation of RE systems. Two separate ACTS technology verification experiments (TVEs) have demonstrated that the portability of the Ultra Small Aperture Terminal (USAT) and the versatility of NASA's Advanced Communications Technology Satellite (ACTS), as well as the advantages of Ka band satellites, can be invaluable in providing energy training via distance education (DE), and for implementing renewable energy system SCADA. What has not been tested is the capabilities of these technologies for a simultaneous implementation of renewable energy DE and SCADA. Such concurrent implementations will be useful for preparing trainees in developing countries for their eventual SCADA operations. The project described in this correspondence is the first effort, to our knowledge, in this specific TVE. The setup for this experiment consists of a one-Watt USAT located at Florida Solar Energy Center (FSEC) connected to two satellite modems tuned to different frequencies to establish two duplex ACTS Ka-band communication channels. A short training program on operation and maintenance of the system will be delivered while simultaneously monitoring and controlling the hybrid using the same satellite

  19. Quantum Cryptography for Secure Communications to Low-Earth Orbit Satellites

    SciTech Connect

    Hughes, R.J.; Buttler, W.T.; Kwiat, P.G.; Lamoreaux, S.K.; Morgan, G.L.; Peterson, C.G.; Twyeffort, E.; Simmons, C.M.; Nordholt, J.E.

    1999-06-03

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Quantum cryptography is an emerging technology in which two parties may simultaneously generate shared, secret cryptographic key material using the transmission of quantum states of light. The security of these transmissions is based on the inviolability of the laws of quantum mechanics. An adversary can neither successfully tap the quantum transmissions, nor evade detection. Key material is built up using the transmission of a single-photon per bit. We have developed an experimental quantum cryptography system based on the transmission of non-orthogonal single-photon polarization states to generate shared key material over line-of-sight optical links. Our results provide strong evidence that cryptographic key material could be generated on demand between a ground station and a satellite (or between two satellites), allowing a satellite to be securely re-keyed on in orbit.

  20. Advanced Communication and Control for Distributed Energy Resource Integration: Phase 2 Scientific Report

    SciTech Connect

    BPL Global

    2008-09-30

    The objective of this research project is to demonstrate sensing, communication, information and control technologies to achieve a seamless integration of multivendor distributed energy resource (DER) units at aggregation levels that meet individual user requirements for facility operations (residential, commercial, industrial, manufacturing, etc.) and further serve as resource options for electric and natural gas utilities. The fully demonstrated DER aggregation system with embodiment of communication and control technologies will lead to real-time, interactive, customer-managed service networks to achieve greater customer value. Work on this Advanced Communication and Control Project (ACCP) consists of a two-phase approach for an integrated demonstration of communication and control technologies to achieve a seamless integration of DER units to reach progressive levels of aggregated power output. Phase I involved design and proof-of-design, and Phase II involves real-world demonstration of the Phase I design architecture. The scope of work for Phase II of this ACCP involves demonstrating the Phase I design architecture in large scale real-world settings while integrating with the operations of one or more electricity supplier feeder lines. The communication and control architectures for integrated demonstration shall encompass combinations of software and hardware components, including: sensors, data acquisition and communication systems, remote monitoring systems, metering (interval revenue, real-time), local and wide area networks, Web-based systems, smart controls, energy management/information systems with control and automation of building energy loads, and demand-response management with integration of real-time market pricing. For Phase II, BPL Global shall demonstrate the Phase I design for integrating and controlling the operation of more than 10 DER units, dispersed at various locations in one or more Independent System Operator (ISO) Control Areas, at

  1. Cryptanalysis and Improvement on "Robust EPR-Pairs-Based Quantum Secure Communication with Authentication Resisting Collective Noise"

    NASA Astrophysics Data System (ADS)

    Yue, Qiu-Ling; Yu, Chao-Hua; Liu, Bin; Wang, Qing-Le

    2016-05-01

    Recently, Chang et al. [Sci Chin-Phys Mech Astron. 57(10), 1907-1912, 2014] proposed two robust quantum secure communication protocols with authentication based on Einstein-Podolsky-Rosen (EPR) pairs, which can resist collective noise. In this paper, we analyze the security of their protocols, and show that there is a kind of security flaw in their protocols. By a kind of impersonation attack, the eavesdropper can obtain half of the message on average. Furthermore, an improved method of their protocols is proposed to close the security loophole.

  2. Cryptanalysis and Improvement on "Robust EPR-Pairs-Based Quantum Secure Communication with Authentication Resisting Collective Noise"

    NASA Astrophysics Data System (ADS)

    Yue, Qiu-Ling; Yu, Chao-Hua; Liu, Bin; Wang, Qing-Le

    2016-10-01

    Recently, Chang et al. [Sci Chin-Phys Mech Astron. 57(10), 1907-1912, 2014] proposed two robust quantum secure communication protocols with authentication based on Einstein-Podolsky-Rosen (EPR) pairs, which can resist collective noise. In this paper, we analyze the security of their protocols, and show that there is a kind of security flaw in their protocols. By a kind of impersonation attack, the eavesdropper can obtain half of the message on average. Furthermore, an improved method of their protocols is proposed to close the security loophole.

  3. Cognitive Mapping of Advanced Level Physics Students' Conceptions of Quantum Physics.

    ERIC Educational Resources Information Center

    Mashhadi, Azam; Woolnough, Brian

    This paper presents findings from a study that investigated students' understanding of quantum phenomena and focused on how students incorporate the ideas of quantum physics into their overall cognitive framework. The heuristic metaphor of the map is used to construct graphic representations of students' understanding of quantum physics. The…

  4. Expected number of quantum channels in quantum networks.

    PubMed

    Chen, Xi; Wang, He-Ming; Ji, Dan-Tong; Mu, Liang-Zhu; Fan, Heng

    2015-01-01

    Quantum communication between nodes in quantum networks plays an important role in quantum information processing. Here, we proposed the use of the expected number of quantum channels as a measure of the efficiency of quantum communication for quantum networks. This measure quantified the amount of quantum information that can be teleported between nodes in a quantum network, which differs from classical case in that the quantum channels will be consumed if teleportation is performed. We further demonstrated that the expected number of quantum channels represents local correlations depicted by effective circles. Significantly, capacity of quantum communication of quantum networks quantified by ENQC is independent of distance for the communicating nodes, if the effective circles of communication nodes are not overlapped. The expected number of quantum channels can be enhanced through transformations of the lattice configurations of quantum networks via entanglement swapping. Our results can shed lights on the study of quantum communication in quantum networks.

  5. Expected number of quantum channels in quantum networks.

    PubMed

    Chen, Xi; Wang, He-Ming; Ji, Dan-Tong; Mu, Liang-Zhu; Fan, Heng

    2015-01-01

    Quantum communication between nodes in quantum networks plays an important role in quantum information processing. Here, we proposed the use of the expected number of quantum channels as a measure of the efficiency of quantum communication for quantum networks. This measure quantified the amount of quantum information that can be teleported between nodes in a quantum network, which differs from classical case in that the quantum channels will be consumed if teleportation is performed. We further demonstrated that the expected number of quantum channels represents local correlations depicted by effective circles. Significantly, capacity of quantum communication of quantum networks quantified by ENQC is independent of distance for the communicating nodes, if the effective circles of communication nodes are not overlapped. The expected number of quantum channels can be enhanced through transformations of the lattice configurations of quantum networks via entanglement swapping. Our results can shed lights on the study of quantum communication in quantum networks. PMID:26173556

  6. Expected number of quantum channels in quantum networks

    PubMed Central

    Chen, Xi; Wang, He-Ming; Ji, Dan-Tong; Mu, Liang-Zhu; Fan, Heng

    2015-01-01

    Quantum communication between nodes in quantum networks plays an important role in quantum information processing. Here, we proposed the use of the expected number of quantum channels as a measure of the efficiency of quantum communication for quantum networks. This measure quantified the amount of quantum information that can be teleported between nodes in a quantum network, which differs from classical case in that the quantum channels will be consumed if teleportation is performed. We further demonstrated that the expected number of quantum channels represents local correlations depicted by effective circles. Significantly, capacity of quantum communication of quantum networks quantified by ENQC is independent of distance for the communicating nodes, if the effective circles of communication nodes are not overlapped. The expected number of quantum channels can be enhanced through transformations of the lattice configurations of quantum networks via entanglement swapping. Our results can shed lights on the study of quantum communication in quantum networks. PMID:26173556

  7. FAST TRACK COMMUNICATION: An effective gravity model and singularity avoidance in quantum FRW cosmologies

    NASA Astrophysics Data System (ADS)

    Haro, Jaume; Elizalde, Emilio

    2009-05-01

    An effective formulation of gravity is discussed, which lies in between the Wheeler-DeWitt approach and that of classical cosmology. It has the virtue of naturally avoiding the singularity that appears in Friedman-Robertson-Walker cosmologies. The mechanism is made explicit in specific examples, where it is compared with the quantization provided by loop quantum cosmology. It is argued that it is the regularization of the classical Hamiltonian, performed in that theory, that avoids the singularity, rather than usually invoked quantum effects. However, a deeper study of the quantum nature of geometry in that framework should help to completely clarify the issue.

  8. Advanced Communication Technology Satellite (ACTS) Multibeam Antenna On-Orbit Performance

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The NASA Lewis Research Center's Advanced Communication Technology Satellite (ACTS) was launched in September 1993. ACTS introduced several new technologies, including a multibeam antenna (MBA) operating at extremely short wavelengths never before used in communications. This antenna, which has both fixed and rapidly reconfigurable high-energy spot beams (150 miles in diameter), serves users equipped with small antenna terminals. Extensive structural and thermal analyses have been performed for simulating the ACTS MBA on-orbit performance. The results show that the reflector surfaces (mainly the front subreflector), antenna support assembly, and metallic surfaces on the spacecraft body will be distorted because of the thermal effects of varying solar heating, which degrade the ACTS MBA performance. Since ACTS was launched, a number of evaluations have been performed to assess MBA performance in the space environment. For example, the on-orbit performance measurements found systematic environmental disturbances to the MBA beam pointing. These disturbances were found to be imposed by the attitude control system, antenna and spacecraft mechanical alignments, and on-orbit thermal effects. As a result, the MBA may not always exactly cover the intended service area. In addition, the on-orbit measurements showed that antenna pointing accuracy is the performance parameter most sensitive to thermal distortions on the front subreflector surface and antenna support assemblies. Several compensation approaches were tested and evaluated to restore on-orbit pointing stability. A combination of autotrack (75 percent of the time) and Earth sensor control (25 percent of the time) was found to be the best way to compensate for antenna pointing error during orbit. This approach greatly minimizes the effects of thermal distortions on antenna beam pointing.

  9. Advances in molecular quantum chemistry contained in the Q-Chem 4 program package

    NASA Astrophysics Data System (ADS)

    Shao, Yihan; Gan, Zhengting; Epifanovsky, Evgeny; Gilbert, Andrew T. B.; Wormit, Michael; Kussmann, Joerg; Lange, Adrian W.; Behn, Andrew; Deng, Jia; Feng, Xintian; Ghosh, Debashree; Goldey, Matthew; Horn, Paul R.; Jacobson, Leif D.; Kaliman, Ilya; Khaliullin, Rustam Z.; Kuś, Tomasz; Landau, Arie; Liu, Jie; Proynov, Emil I.; Rhee, Young Min; Richard, Ryan M.; Rohrdanz, Mary A.; Steele, Ryan P.; Sundstrom, Eric J.; Woodcock, H. Lee, III; Zimmerman, Paul M.; Zuev, Dmitry; Albrecht, Ben; Alguire, Ethan; Austin, Brian; Beran, Gregory J. O.; Bernard, Yves A.; Berquist, Eric; Brandhorst, Kai; Bravaya, Ksenia B.; Brown, Shawn T.; Casanova, David; Chang, Chun-Min; Chen, Yunqing; Chien, Siu Hung; Closser, Kristina D.; Crittenden, Deborah L.; Diedenhofen, Michael; DiStasio, Robert A., Jr.; Do, Hainam; Dutoi, Anthony D.; Edgar, Richard G.; Fatehi, Shervin; Fusti-Molnar, Laszlo; Ghysels, An; Golubeva-Zadorozhnaya, Anna; Gomes, Joseph; Hanson-Heine, Magnus W. D.; Harbach, Philipp H. P.; Hauser, Andreas W.; Hohenstein, Edward G.; Holden, Zachary C.; Jagau, Thomas-C.; Ji, Hyunjun; Kaduk, Benjamin; Khistyaev, Kirill; Kim, Jaehoon; Kim, Jihan; King, Rollin A.; Klunzinger, Phil; Kosenkov, Dmytro; Kowalczyk, Tim; Krauter, Caroline M.; Lao, Ka Un; Laurent, Adèle D.; Lawler, Keith V.; Levchenko, Sergey V.; Lin, Ching Yeh; Liu, Fenglai; Livshits, Ester; Lochan, Rohini C.; Luenser, Arne; Manohar, Prashant; Manzer, Samuel F.; Mao, Shan-Ping; Mardirossian, Narbe; Marenich, Aleksandr V.; Maurer, Simon A.; Mayhall, Nicholas J.; Neuscamman, Eric; Oana, C. Melania; Olivares-Amaya, Roberto; O'Neill, Darragh P.; Parkhill, John A.; Perrine, Trilisa M.; Peverati, Roberto; Prociuk, Alexander; Rehn, Dirk R.; Rosta, Edina; Russ, Nicholas J.; Sharada, Shaama M.; Sharma, Sandeep; Small, David W.; Sodt, Alexander; Stein, Tamar; Stück, David; Su, Yu-Chuan; Thom, Alex J. W.; Tsuchimochi, Takashi; Vanovschi, Vitalii; Vogt, Leslie; Vydrov, Oleg; Wang, Tao; Watson, Mark A.; Wenzel, Jan; White, Alec; Williams, Christopher F.; Yang, Jun; Yeganeh, Sina; Yost, Shane R.; You, Zhi-Qiang; Zhang, Igor Ying; Zhang, Xing; Zhao, Yan; Brooks, Bernard R.; Chan, Garnet K. L.; Chipman, Daniel M.; Cramer, Christopher J.; Goddard, William A., III; Gordon, Mark S.; Hehre, Warren J.; Klamt, Andreas; Schaefer, Henry F., III; Schmidt, Michael W.; Sherrill, C. David; Truhlar, Donald G.; Warshel, Arieh; Xu, Xin; Aspuru-Guzik, Alán; Baer, Roi; Bell, Alexis T.; Besley, Nicholas A.; Chai, Jeng-Da; Dreuw, Andreas; Dunietz, Barry D.; Furlani, Thomas R.; Gwaltney, Steven R.; Hsu, Chao-Ping; Jung, Yousung; Kong, Jing; Lambrecht, Daniel S.; Liang, WanZhen; Ochsenfeld, Christian; Rassolov, Vitaly A.; Slipchenko, Lyudmila V.; Subotnik, Joseph E.; Van Voorhis, Troy; Herbert, John M.; Krylov, Anna I.; Gill, Peter M. W.; Head-Gordon, Martin

    2015-01-01

    A summary of the technical advances that are incorporated in the fourth major release of the Q-Chem quantum chemistry program is provided, covering approximately the last seven years. These include developments in density functional theory methods and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and open-shell species, tools for treating extended environments, algorithms for walking on potential surfaces, analysis tools, energy and electron transfer modelling, parallel computing capabilities, and graphical user interfaces. In addition, a selection of example case studies that illustrate these capabilities is given. These include extensive benchmarks of the comparative accuracy of modern density functionals for bonded and non-bonded interactions, tests of attenuated second order Møller-Plesset (MP2) methods for intermolecular interactions, a variety of parallel performance benchmarks, and tests of the accuracy of implicit solvation models. Some specific chemical examples include calculations on the strongly correlated Cr2 dimer, exploring zeolite-catalysed ethane dehydrogenation, energy decomposition analysis of a charged ter-molecular complex arising from glycerol photoionisation, and natural transition orbitals for a Frenkel exciton state in a nine-unit model of a self-assembling nanotube.

  10. Advances in quantum cascade lasers for security and crime-fighting

    NASA Astrophysics Data System (ADS)

    Normand, Erwan L.; Stokes, Robert J.; Hay, Kenneth; Foulger, Brian; Lewis, Colin

    2010-10-01

    Advances in the application of Quantum Cascade Lasers (QCL) to trace gas detection will be presented. The solution is real time (~1 μsec per scan), is insensitive to turbulence and vibration, and performs multiple measurements in one sweep. The QCL provides a large dynamic range, which is a linear response from ppt to % level. The concentration can be derived with excellent immunity from cross interference. Point sensing sensors developed by Cascade for home made and commercial explosives operate by monitoring key constituents in real time and matching this to a spatial event (i.e. sniffer device placed close to an object or person walking through portal (overt or covert). Programmable signature detection capability allows for detection of multiple chemical compounds along the most likely array of explosive chemical formulation. The advantages of configuration as "point sensing" or "stand off" will be discussed. In addition to explosives this method is highly applicable to the detection of mobile drugs labs through volatile chemical release.

  11. FAST TRACK COMMUNICATION: Singularity avoidance in quantum FRW cosmologies in the presence of barotropic perfect fluids

    NASA Astrophysics Data System (ADS)

    Elizalde, Emilio; Haro, Jaume

    2009-11-01

    Recently, an effective formulation of gravity which lies in between the Wheeler-DeWitt approach and classical cosmology was discussed. It was shown that the Big Bang singularity of FRW cosmologies is avoided in a quite natural way. Here, we aim to prove that this formulation is able to avoid the Big Rip singularity too, in contradistinction with Schutz's formalism as applied to quantum cosmological perfect fluids. Actually, in using this last formalism, some authors have argued that such singularity would persist even after quantization, however, what we carried out, with our formulation as a guide, proved not to be the case. Also, it will be argued that it is the implicit regularization of the classical Hamiltonian performed in loop quantum cosmology, which is needed in loop cosmology in order to build a well-defined quantum (discrete) theory, which avoids the Big Rip singularity in that theory, this mechanism being different from other, ordinarily invoked quantum effects.

  12. Advanced Communication and Control of Distributed Energy Resources at Detroit Edison

    SciTech Connect

    Haukur Asgeirsson; Richard Seguin

    2004-01-31

    (Utility) led team, which also includes: DTE Energy Technology (DER provider & Aggregator), Electrical Distribution Design (Virginia Tech company supporting DEW); Systems Integration Specialists Company (real-time protocol integrator); and OSIsoft (software system for managing real-time information). This work was performed in anticipation of being selected for Phase II of the Advanced Communication and Control of Distributed Energy Resources project.

  13. Quantum Hall effect in bilayer systems and the noncommutative plane: A toy model approach [rapid communication

    NASA Astrophysics Data System (ADS)

    Basu, B.; Ghosh, Subir

    2005-10-01

    We have presented a quantum mechanical toy model for the study of Coulomb interactions in Quantum Hall (QH) system. Inclusion of Coulomb interaction is essential for the study of bilayer QH system and our model can simulate it, in the compound state, in a perturbative framework. We also show that in the noncommutative plane, the Coulomb interaction is modified at a higher order in the noncommutativity parameter θ, and only if θ varies from layer to layer in the QH system.

  14. Communication

    NASA Technical Reports Server (NTRS)

    Griner, James

    2010-01-01

    NASA s communication work for the UAS Command and Control area will build upon work currently being conducted under NASA Recovery Act funds. Communication portions of UAS NextGen ConOps, Stateof- the-Art assessment, and Gap Analysis. Preliminary simulations for UAS CNPC link scalability assessment. Surrogate UAS aircraft upgrades. This work will also leverage FY10 in-guide funding for communication link model development. UAS are currently managed through exceptions and are operating using DoD frequencies for line-of-sight (LOS) and satellite-based communications links, low-power LOS links in amateur bands, or unlicensed Instrument/Scientific/Medical (ISM) frequencies. None of these frequency bands are designated for Safety and Regularity of Flight. No radio-frequency (RF) spectrum has been allocated by the International Telecommunications Union (ITU) specifically for UAS command and control links, for either LOS or Beyond LOS (BLOS) communication.

  15. An operational approach to spacetime symmetries: Lorentz transformations from quantum communication

    NASA Astrophysics Data System (ADS)

    Höhn, Philipp A.; Müller, Markus P.

    2016-06-01

    In most approaches to fundamental physics, spacetime symmetries are postulated a priori and then explicitly implemented in the theory. This includes Lorentz covariance in quantum field theory and diffeomorphism invariance in quantum gravity, which are seen as fundamental principles to which the final theory has to be adjusted. In this paper, we suggest, within a much simpler setting, that this kind of reasoning can actually be reversed, by taking an operational approach inspired by quantum information theory. We consider observers in distinct laboratories, with local physics described by the laws of abstract quantum theory, and without presupposing a particular spacetime structure. We ask what information-theoretic effort the observers have to spend to synchronize their descriptions of local physics. If there are ‘enough’ observables that can be measured universally on several different quantum systems, we show that the observers’ descriptions are related by an element of the orthochronous Lorentz group {{{O}}}+(3,1), together with a global scaling factor. Not only does this operational approach predict the Lorentz transformations, but it also accurately describes the behavior of relativistic Stern-Gerlach devices in the WKB approximation, and it correctly predicts that quantum systems carry Lorentz group representations of different spin. This result thus hints at a novel information-theoretic perspective on spacetime.

  16. Advanced Communications Technology Satellite (ACTS) Fade Compensation Protocol Impact on Very Small-Aperture Terminal Bit Error Rate Performance

    NASA Technical Reports Server (NTRS)

    Cox, Christina B.; Coney, Thom A.

    1999-01-01

    The Advanced Communications Technology Satellite (ACTS) communications system operates at Ka band. ACTS uses an adaptive rain fade compensation protocol to reduce the impact of signal attenuation resulting from propagation effects. The purpose of this paper is to present the results of an analysis characterizing the improvement in VSAT performance provided by this protocol. The metric for performance is VSAT bit error rate (BER) availability. The acceptable availability defined by communication system design specifications is 99.5% for a BER of 5E-7 or better. VSAT BER availabilities with and without rain fade compensation are presented. A comparison shows the improvement in BER availability realized with rain fade compensation. Results are presented for an eight-month period and for 24 months spread over a three-year period. The two time periods represent two different configurations of the fade compensation protocol. Index Terms-Adaptive coding, attenuation, propagation, rain, satellite communication, satellites.

  17. Neutron Matter Wave Quantum Optics

    NASA Astrophysics Data System (ADS)

    Rauch, Helmut

    2012-06-01

    Neutron matter-wave optics provides the basis for new quantum experiments and a step towards applications of quantum phenomena. Most experiments have been performed with a perfect crystal neutron interferometer where widely separated coherent beams can be manipulated individually. Various geometric phases have been measured and their robustness against fluctuation effects has been proven, which may become a useful property for advanced quantum communication. Quantum contextuality for single particle systems shows that quantum correlations are to some extent more demanding than classical ones. In this case entanglement between external and internal degrees of freedom offers new insights into basic laws of quantum physics. Non-contextuality hidden variable theories can be rejected by arguments based on the Kochen-Specker theorem.

  18. Teleradiology and telemedicine using the advanced communications technology satellite and international maritime satellite at varying bandwidths

    NASA Astrophysics Data System (ADS)

    de Treville, Robert E.; Scotti, Stephen D.; Williamson, Morgan P.; Olson, Eric J.; Brink, Linda; Isle, Ken; Kafaro, Peter

    1995-05-01

    The United States military gained experience with a deployed telemedicine team and unit during the deployment of United States military troops to Haiti as part of `Operation Uphold Democracy.' Consults were conducted primarily between the 28th combat support hospital in Haiti and Walter Reed Army Medical Center in Washington, D.C. The Advanced Communications Technology Satellite and International Maritime Satellite services were used for telecommunications during the deployment. A total of 30 telemedicine consultations were performed during the deployment. All consultations were conducted prospectively, and data was entered in a database for later review. Treatment plans and plans for patient disposition were recorded prior to consultation. Following completion of the telemedicine consultations, each case was reviewed to determine the impact of the telemedicine consult upon the treatment plan or disposition. Fifty percent of the consultations resulted in a significant modification in the patient's treatment plan. Seventeen percent resulted in a significant or possible change in evacuation planning. The most frequently used consultants were the dermatologists, radiologists, and hand surgeons. This experience demonstrates that telemedicine can be used effectively in a deployed military environment. In addition, the ability to obtain remote consultations does impact upon medical treatment and upon medical evacuation. Having support personnel in the field was found to be an important factor in utilization of the system.

  19. Controlled quantum secure communication protocol with single photons in both polarization and spatial-mode degrees of freedom

    NASA Astrophysics Data System (ADS)

    Wang, Lili; Ma, Wenping

    2016-02-01

    In this paper, we propose a new controlled quantum secure direct communication (CQSDC) protocol with single photons in both polarization and spatial-mode degrees of freedom. Based on the defined local collective unitary operations, the sender’s secret messages can be transmitted directly to the receiver through encoding secret messages on the particles. Only with the help of the third side, the receiver can reconstruct the secret messages. Each single photon in two degrees of freedom can carry two bits of information, so the cost of our protocol is less than others using entangled qubits. Moreover, the security of our QSDC network protocol is discussed comprehensively. It is shown that our new CQSDC protocol cannot only defend the outsider eavesdroppers’ several sorts of attacks but also the inside attacks. Besides, our protocol is feasible since the preparation and the measurement of single photon quantum states in both the polarization and the spatial-mode degrees of freedom are available with current quantum techniques.

  20. Cryptanalysis of Controlled Quantum Secure Direct Communication and Authentication Protocol Based on Five-Particle Cluster State and Quantum One-Time Pad

    NASA Astrophysics Data System (ADS)

    Liu, Zhihao; Chen, Hanwu; Liu, Wenjie

    2016-10-01

    A new attack strategy, the so-called intercept-selectively-measure-resend attack is put forward. It shows that there are some security issues in the controlled quantum secure direct communication (CQSDC) and authentication protocol based on five-particle cluster states and quantum one-time pad. Firstly, an eavesdropper (Eve) can use this attack to eavesdrop on 0.656 bit of every bit of the identity string of the receiver and 1.406 bits of every couple of the corresponding bits of the secret message without being detected. Also, she can eavesdrop on 0.311 bit of every bit of the identity string of the controller. Secondly, the receiver can also take this attack to obtain 1.311 bits of every couple of the corresponding bits of the secret message without the permission of the controller, which is not allowed in the CQSDC protocols. In fact, there is another security issue in this protocol, that is, one half of the information about the secret is leaked out unconsciously. In addition, an alternative attack strategy which is called as the selective-CNOT-operation attack strategy to attack this protocol is discussed.

  1. Cryptanalysis of Controlled Quantum Secure Direct Communication and Authentication Protocol Based on Five-Particle Cluster State and Quantum One-Time Pad

    NASA Astrophysics Data System (ADS)

    Liu, Zhihao; Chen, Hanwu; Liu, Wenjie

    2016-06-01

    A new attack strategy, the so-called intercept-selectively-measure-resend attack is put forward. It shows that there are some security issues in the controlled quantum secure direct communication (CQSDC) and authentication protocol based on five-particle cluster states and quantum one-time pad. Firstly, an eavesdropper (Eve) can use this attack to eavesdrop on 0.656 bit of every bit of the identity string of the receiver and 1.406 bits of every couple of the corresponding bits of the secret message without being detected. Also, she can eavesdrop on 0.311 bit of every bit of the identity string of the controller. Secondly, the receiver can also take this attack to obtain 1.311 bits of every couple of the corresponding bits of the secret message without the permission of the controller, which is not allowed in the CQSDC protocols. In fact, there is another security issue in this protocol, that is, one half of the information about the secret is leaked out unconsciously. In addition, an alternative attack strategy which is called as the selective-CNOT-operation attack strategy to attack this protocol is discussed.

  2. Recent Efforts in Advanced High Frequency Communications at the Glenn Research Center in Support of NASA Mission

    NASA Technical Reports Server (NTRS)

    Miranda, Felix A.

    2015-01-01

    This presentation will discuss research and technology development work at the NASA Glenn Research Center in advanced frequency communications in support of NASAs mission. An overview of the work conducted in-house and also in collaboration with academia, industry, and other government agencies (OGA) in areas such as antenna technology, power amplifiers, radio frequency (RF) wave propagation through Earths atmosphere, ultra-sensitive receivers, among others, will be presented. In addition, the role of these and other related RF technologies in enabling the NASA next generation space communications architecture will be also discussed.

  3. Proceedings of the Seventeenth NASA Propagation Experimenters Meeting (NAPEX 17) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop

    NASA Technical Reports Server (NTRS)

    Davarian, Faramaz (Editor)

    1993-01-01

    The NASA Propagation Experimenters Meeting (NAPEX) is convened annually to discuss studies made on radio wave propagation by investors from domestic and international organizations. NAPEX 17 was held on 15 June 1993. The meeting was organized into two technical sessions. The first session was dedicated to slant path propagation studies and experiments. The second session focused on propagation studies for mobile and personal communications. Preceding NAPEX 17, the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop was held on 14 June 1993 to review ACTS propagation activities with emphasis on ACTS experiments status and data collection, processing, and exchange.

  4. Fiber-coupled quantum-communications receiver based on two NbN superconducting single-photon detectors

    NASA Astrophysics Data System (ADS)

    Slysz, W.; Wegrzecki, M.; Bar, J.; Grabiec, P.; Górska, M.; Latta, C.; Zwiller, V.; Pearlman, A.; Cross, A.; Korneev, A.; Kouminov, P.; Smirnov, K.; Voronov, B.; Gol'tsman, G.; Verevkin, A.; Currie, M.; Sobolewski, R.

    2005-09-01

    We present the design and performance of a novel, two-channel single-photon receiver, based on two fiber-coupled NbN superconducting single-photon detectors (SSPDs). The SSPDs are nanostructured superconducting meanders covering an area of 100 μm2 and are known for ultrafast and efficient counting of single, visible-to-infrared photons. Their operation has been explained within a phenomenological hot-electron photoresponse model. Our receiver is intended for fiber-based quantum cryptography and communication systems, operational at near-infrared (NIR) telecommunication wavelengths, λ = 1.3 μm and λ = 1.55 μm. Coupling between the NbN detector and a single-mode optical fiber was achieved using a specially designed, micromechanical photoresist ring, positioned directly over the SSPD active area. The positioning accuracy of the ring was below 1 μm. The receiver with SSPDs was placed (immersed) in a standard liquid-helium transport Dewar and kept without interruption for over two months at 4.2 K. At the same time, the optical fiber inputs and electrical outputs were kept at room temperature. Our best system reached a system quantum efficiency of up to 0.3 % in the NIR radiation range, with the detector coupling efficiency of about 30 %. The response time was measured to be about 250 ps and was limited by our read-out electronics. The measured jitter was close to 35 ps. The presented performance parameters show that our NIR single photon detectors are suitable for practical quantum cryptography and for applications in quantum-correlation experiments.

  5. Modular space station, phase B extension. Information management advanced development. Volume 2: Communications terminal breadboard

    NASA Technical Reports Server (NTRS)

    Gerber, C. R.

    1972-01-01

    The design and development of the communications terminal breadboard for the modular space station are discussed. The subjects presented are: (1) history of communications terminal breadboard, (2) requirements analysis, (3) technology goals in terminal design, and (4) communications terminal board integration tests.

  6. FAST TRACK COMMUNICATION: A Temperley-Lieb quantum chain with two- and three-site interactions

    NASA Astrophysics Data System (ADS)

    Ikhlef, Y.; Jacobsen, J. L.; Saleur, H.

    2009-07-01

    We study the phase diagram of a quantum chain of spin-1/2 particles whose world lines form a dense loop gas with loop weight n. In addition to the usual two-site interaction corresponding to the XXZ spin chain, we introduce a three-site interaction. The resulting model contains a Majumdar-Ghosh-like gapped phase and a new integrable point, which we solve exactly. We also locate a critical line realizing dilute O(n) criticality, without introducing explicit dilution in the loops. Our results have implications for anisotropic spin chains, as well as anyonic quantum chains.

  7. Full polarization control for fiber optical quantum communication systems using polarization encoding.

    PubMed

    Xavier, G B; Vilela de Faria, G; Temporão, G P; von der Weid, J P

    2008-02-01

    A real-time polarization control system employing two non-orthogonal reference signals multiplexed in either time or wavelength with the data signal is presented. It is shown, theoretically and experimentally, that complete control of multiple polarization states can be attained employing polarization controllers in closed-loop configuration. Experimental results on the wavelength multiplexing setup show that negligible added penalties, corresponding to an average added optical Quantum Bit Error Rate of 0.044%, can be achieved with response times smaller than 10 ms, without significant introduction of noise counts in the quantum channel.

  8. A research on service quality decision-making of Chinese communications industry based on quantum game

    NASA Astrophysics Data System (ADS)

    Zhang, Cuihua; Xing, Peng

    2015-08-01

    In recent years, Chinese service industry is developing rapidly. Compared with developed countries, service quality should be the bottleneck for Chinese service industry. On the background of three major telecommunications service providers in China, the functions of customer perceived utilities are established. With the goal of consumer's perceived utility maximization, the classic Nash equilibrium solution and quantum equilibrium solution are obtained. Then a numerical example is studied and the changing trend of service quality and customer perceived utility is further analyzed by the influence of the entanglement operator. Finally, it is proved that quantum game solution is better than Nash equilibrium solution.

  9. Use of CCSDS and OSI Protocols on the Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Chirieleison, Don

    1996-01-01

    Although ACTS (Advanced Communications Technology Satellite) provides an almost error-free channel during much of the day and under most conditions, there are times when it is not suitable for reliably error-free data communications when operating in the uncoded mode. Because coded operation is not always available to every earth station, measures must be taken in the end system to maintain adequate throughput when transferring data under adverse conditions. The most effective approach that we tested to improve performance was the addition of an 'outer' Reed-Solomon code through use of CCSDS (Consultative Committee for Space Data Systems) GOS 2 (a forward error correcting code). This addition can benefit all users of an ACTS channel including those applications that do not require totally reliable transport, but it is somewhat expensive because additional hardware is needed. Although we could not characterize the link noise statistically (it appeared to resemble uncorrelated white noise, the type that block codes are least effective in correcting), we did find that CCSDS GOS 2 gave an essentially error-free link at BER's (bit error rate) as high as 6x10(exp -4). For users that demand reliable transport, an ARQ (Automatic Repeat Queuing) protocol such as TCP (Transmission Control Protocol) or TP4 (Transport Protocol, Class 4) will probably be used. In this category, it comes as no surprise that the best choice of the protocol suites tested over ACTS was TP4 using CCSDS GOS 2. TP4 behaves very well over an error-free link which GOS 2 provides up to a point. Without forward error correction, however, TP4 service begins to degrade in the 10(exp -7)-10(exp -6) range and by 4x10(exp -6), it barely gives any throughput at all. If Congestion Avoidance is used in TP4, the degradation is even more pronounced. Fortunately, as demonstrated here, this effect can be more than compensated for by choosing the Selective Acknowledgment option. In fact, this option can enable TP4 to

  10. Nonlocal quantum gate on quantum continuous variables with minimal resources

    NASA Astrophysics Data System (ADS)

    Yokoyama, Shota; Ukai, Ryuji; Yoshikawa, Jun-ichi; Marek, Petr; Filip, Radim; Furusawa, Akira

    2014-07-01

    We experimentally demonstrate, with an all-optical setup, a nonlocal deterministic quantum nondemolition interaction gate applicable to quantum states at nodes separated by a physical distance and connected by classical communication channels. The gate implementation, based on entangled states shared in advance, local operations, and classical communication, runs completely in parallel fashion at both of the local nodes, requiring minimum resources. The nondemolition character of the gate up to the local unitary squeezing is verified by the analysis using several coherent states. A genuine quantum nature of the gate is confirmed by the capability of deterministically producing an entangled state at the output from two separable input states. The all-optical nonlocal gate operation can be potentially incorporated into distributed quantum computing with atomic or solid-state systems as a cross-processor unitary operation.

  11. Influence of satellite motion on polarization qubits in a Space-Earth quantum communication link.

    PubMed

    Bonato, Cristian; Aspelmeyer, Markus; Jennewein, Thomas; Pernechele, Claudio; Villoresi, Paolo; Zeilinger, Anton

    2006-10-16

    In a Space quantum-cryptography experiment a satellite pointing system is needed to send single photons emitted by the source on the satellite to the polarization analysis apparatus on Earth. In this paper a simulation is presented regarding how the satellite pointing systems affect the polarization state of the single photons, to help designing a proper compensation system.

  12. Proposal of a Communications Theory of Quantum Mechanics. Theoretical Examination of the 'Gyromagnetic Ratio'

    SciTech Connect

    Coogan, Anthony

    2009-03-09

    Is the 'Two-Slit' experiment best explained by aliasing, first solved by Harry Nyquist (1926)? Does light reflected by an electron rotate through double the angle through which the electron itself rotates? Can a barchart represent the uncertainty principle?A very simple model of quantum mechanics is presented.

  13. The environment-pathogen-host axis in communicable and non-communicable diseases: recent advances in experimental and clinical research.

    PubMed

    Gilles, Stefanie; Traidl-Hoffmann, Claudia

    2014-05-01

    Allergies and autoimmune diseases are spreading worldwide. Control of infections, on the other hand, remains an issue, even in the post-antibiotic era. Chronic or poorly controlled infections occur in immune compromised individuals such as HIV patients, hospitalized patients exposed to multi-resistant bacteria, or patients on immunosuppressive treatment. They may become an even more emerging issue in an ageing population. At the same time, profound environmental changes such as global warming, urbanization, increasing environmental pollution and novel food engineering technologies may alter the abundance or aggressiveness of allergens/allergen carriers in our environment. Likewise, changes in dietary habits - and possibly also use of antibiotics - have an impact on the composition of our natural microbial flora in the gut, airways and skin, which may alter susceptibility for common diseases, among them allergies, asthma and atopic eczema. At the recently founded Institute of Environmental Medicine of the Technische Universität Munich, located in Augsburg at the UNIKA-T, experimental, clinical and translational research is focused on the complex interactions of environment, pathogen and host in expression or control of communicable and non-communicable diseases. We present our research concept and recent findings in environment - host interactions.

  14. Communications

    ERIC Educational Resources Information Center

    Bailenson, Jeremy; Buzzanell, Patrice; Deetz, Stanley; Tewksbury, David; Thompson, Robert J.; Turow, Joseph; Bichelmeyer, Barbara; Bishop, M. J.; Gayeski, Diane

    2013-01-01

    Scholars representing the field of communications were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might change our understanding. The scholars included Jeremy Bailenson, Patrice Buzzanell, Stanley Deetz, David Tewksbury, Robert J. Thompson, and…

  15. Experimental quantum teleportation and multiphoton entanglement via interfering narrowband photon sources

    SciTech Connect

    Yang Jian; Zhang Han; Peng Chengzhi; Chen Zengbing; Bao Xiaohui; Chen Shuai; Pan Jianwei

    2009-10-15

    In this paper, we report a realization of synchronization-free quantum teleportation and narrowband three-photon entanglement through interfering narrowband photon sources. Since both the single-photon and the entangled photon pair utilized are completely autonomous, it removes the requirement of high-demanding synchronization techniques in long-distance quantum communication with pulsed spontaneous parametric down-conversion sources. The frequency linewidth of the three-photon entanglement realized is on the order of several MHz, which matches the requirement of atomic ensemble based quantum memories. Such a narrowband multiphoton source will have applications in some advanced quantum communication protocols and linear optical quantum computation.

  16. Strategies for measurement-based quantum computation with cluster states transformed by stochastic local operations and classical communication

    SciTech Connect

    D'Souza, Adam G.; Feder, David L.

    2011-10-15

    We examine cluster states transformed by stochastic local operations and classical communication, as a resource for deterministic universal computation driven strictly by projective measurements. We identify circumstances under which such states in one dimension constitute resources for random-length single-qubit rotations, in one case quasideterministically (N-U-N states) and in another probabilistically (B-U-B states). In contrast to the cluster states, the N-U-N states exhibit spin correlation functions that decay exponentially with distance, while the B-U-B states can be arbitrarily locally pure. A two-dimensional square N-U-N lattice is a universal resource for quasideterministic measurement-based quantum computation. Measurements on cubic B-U-B states yield two-dimensional cluster states with bond defects, whose connectivity exceeds the percolation threshold for a critical value of the local purity.

  17. Communication: Adiabatic and non-adiabatic electron-nuclear motion: Quantum and classical dynamics

    NASA Astrophysics Data System (ADS)

    Albert, Julian; Kaiser, Dustin; Engel, Volker

    2016-05-01

    Using a model for coupled electronic-nuclear motion we investigate the range from negligible to strong non-adiabatic coupling. In the adiabatic case, the quantum dynamics proceeds in a single electronic state, whereas for strong coupling a complete transition between two adiabatic electronic states takes place. It is shown that in all coupling regimes the short-time wave-packet dynamics can be described using ensembles of classical trajectories in the phase space spanned by electronic and nuclear degrees of freedom. We thus provide an example which documents that the quantum concept of non-adiabatic transitions is not necessarily needed if electronic and nuclear motion is treated on the same footing.

  18. Hamiltonian of photons in a single-mode optical fiber for quantum communications protocols

    NASA Astrophysics Data System (ADS)

    Miroshnichenko, G. P.

    2012-05-01

    A phenomenological Hamiltonian of photons in a single-mode stochastic inhomogeneous optical fiber (OF) is derived. Quantization of radiation is performed in the basis of an ideal OF with proper calibration that ensures transversality of the electric-field-displacement vector. Stochastic parameters of the Hamiltonian are determined by using the reciprocal tensor of the dielectric permittivity averaged over the OF segment volume. The Hamiltonian is parametrized by three phenomenological parameters and preserves the number of photons. It is assumed that the segment of the OF is divided into random subsegments with optical parameters defined by the Wiener process with respect to the longitudinal coordinate. The temporal dynamics of the single-photon density matrix is analyzed in the basis of states with orthogonal polarizations. The relative quantum beat error rate in the sifted quantum key distributed according to the BB84 protocol with polarization coding of information averaged over the scatter of the OF parameters is calculated.

  19. Communication: Relation of centroid molecular dynamics and ring-polymer molecular dynamics to exact quantum dynamics

    SciTech Connect

    Hele, Timothy J. H.; Willatt, Michael J.; Muolo, Andrea; Althorpe, Stuart C.

    2015-05-21

    We recently obtained a quantum-Boltzmann-conserving classical dynamics by making a single change to the derivation of the “Classical Wigner” approximation. Here, we show that the further approximation of this “Matsubara dynamics” gives rise to two popular heuristic methods for treating quantum Boltzmann time-correlation functions: centroid molecular dynamics (CMD) and ring-polymer molecular dynamics (RPMD). We show that CMD is a mean-field approximation to Matsubara dynamics, obtained by discarding (classical) fluctuations around the centroid, and that RPMD is the result of discarding a term in the Matsubara Liouvillian which shifts the frequencies of these fluctuations. These findings are consistent with previous numerical results and give explicit formulae for the terms that CMD and RPMD leave out.

  20. Communication: Relation of centroid molecular dynamics and ring-polymer molecular dynamics to exact quantum dynamics.

    PubMed

    Hele, Timothy J H; Willatt, Michael J; Muolo, Andrea; Althorpe, Stuart C

    2015-05-21

    We recently obtained a quantum-Boltzmann-conserving classical dynamics by making a single change to the derivation of the "Classical Wigner" approximation. Here, we show that the further approximation of this "Matsubara dynamics" gives rise to two popular heuristic methods for treating quantum Boltzmann time-correlation functions: centroid molecular dynamics (CMD) and ring-polymer molecular dynamics (RPMD). We show that CMD is a mean-field approximation to Matsubara dynamics, obtained by discarding (classical) fluctuations around the centroid, and that RPMD is the result of discarding a term in the Matsubara Liouvillian which shifts the frequencies of these fluctuations. These findings are consistent with previous numerical results and give explicit formulae for the terms that CMD and RPMD leave out.

  1. Communication: Adiabatic and non-adiabatic electron-nuclear motion: Quantum and classical dynamics.

    PubMed

    Albert, Julian; Kaiser, Dustin; Engel, Volker

    2016-05-01

    Using a model for coupled electronic-nuclear motion we investigate the range from negligible to strong non-adiabatic coupling. In the adiabatic case, the quantum dynamics proceeds in a single electronic state, whereas for strong coupling a complete transition between two adiabatic electronic states takes place. It is shown that in all coupling regimes the short-time wave-packet dynamics can be described using ensembles of classical trajectories in the phase space spanned by electronic and nuclear degrees of freedom. We thus provide an example which documents that the quantum concept of non-adiabatic transitions is not necessarily needed if electronic and nuclear motion is treated on the same footing.

  2. Communication: Fixed-node errors in quantum Monte Carlo: Interplay of electron density and node nonlinearities

    SciTech Connect

    Rasch, Kevin M.; Hu, Shuming; Mitas, Lubos

    2014-01-28

    We elucidate the origin of large differences (two-fold or more) in the fixed-node errors between the first- vs second-row systems for single-configuration trial wave functions in quantum Monte Carlo calculations. This significant difference in the valence fixed-node biases is studied across a set of atoms, molecules, and also Si, C solid crystals. We show that the key features which affect the fixed-node errors are the differences in electron density and the degree of node nonlinearity. The findings reveal how the accuracy of the quantum Monte Carlo varies across a variety of systems, provide new perspectives on the origins of the fixed-node biases in calculations of molecular and condensed systems, and carry implications for pseudopotential constructions for heavy elements.

  3. No signaling and quantum key distribution.

    PubMed

    Barrett, Jonathan; Hardy, Lucien; Kent, Adrian

    2005-07-01

    Standard quantum key distribution protocols are provably secure against eavesdropping attacks, if quantum theory is correct. It is theoretically interesting to know if we need to assume the validity of quantum theory to prove the security of quantum key distribution, or whether its security can be based on other physical principles. The question would also be of practical interest if quantum mechanics were ever to fail in some regime, because a scientifically and technologically advanced eavesdropper could perhaps use postquantum physics to extract information from quantum communications without necessarily causing the quantum state disturbances on which existing security proofs rely. Here we describe a key distribution scheme provably secure against general attacks by a postquantum eavesdropper limited only by the impossibility of superluminal signaling. Its security stems from violation of a Bell inequality.

  4. Scaling the ion trap quantum processor.

    PubMed

    Monroe, C; Kim, J

    2013-03-01

    Trapped atomic ions are standards for quantum information processing, serving as quantum memories, hosts of quantum gates in quantum computers and simulators, and nodes of quantum communication networks. Quantum bits based on trapped ions enjoy a rare combination of attributes: They have exquisite coherence properties, they can be prepared and measured with nearly 100% efficiency, and they are readily entangled with each other through the Coulomb interaction or remote photonic interconnects. The outstanding challenge is the scaling of trapped ions to hundreds or thousands of qubits and beyond, at which scale quantum processors can outperform their classical counterparts in certain applications. We review the latest progress and prospects in that effort, with the promise of advanced architectures and new technologies, such as microfabricated ion traps and integrated photonics.

  5. United by Goals: There Is No Integrated Advancement without Communications and Marketing

    ERIC Educational Resources Information Center

    DiConsiglio, John

    2011-01-01

    The idea behind integrated advancement is simple and dates back to the 1990s: A strong relationship between advancement offices conserves resources. It leads to a more efficient workforce. It portrays a highly unified message to stakeholders, including donors, alumni, local officials, and opinion leaders. In short, the entire advancement team…

  6. Complete pulse characterization of quantum dot mode-locked lasers suitable for optical communication up to 160 Gbit/s.

    PubMed

    Schmeckebier, H; Fiol, G; Meuer, C; Arsenijević, D; Bimberg, D

    2010-02-15

    A complete characterization of pulse shape and phase of a 1.3 microm, monolithic-two-section, quantum-dot mode-locked laser (QD-MLL) at a repetition rate of 40 GHz is presented, based on frequency resolved optical gating. We show that the pulse broadening of the QD-MLL is caused by linear chirp for all values of current and voltage investigated here. The chirp increases with the current at the gain section, whereas larger bias at the absorber section leads to less chirp and therefore to shorter pulses. Pulse broadening is observed at very high bias, likely due to the quantum confined stark effect. Passive- and hybrid-QD-MLL pulses are directly compared. Improved pulse intensity profiles are found for hybrid mode locking. Via linear chirp compensation pulse widths down to 700 fs can be achieved independent of current and bias, resulting in a significantly increased overall mode-locking range of 101 MHz. The suitability of QD-MLL chirp compensated pulse combs for optical communication up to 160 Gbit/s using optical-time-division multiplexing are demonstrated by eye diagrams and autocorrelation measurements.

  7. Robust quantum secure direct communication and authentication protocol against decoherence noise based on six-qubit DF state

    NASA Astrophysics Data System (ADS)

    Chang, Yan; Zhang, Shi-Bin; Yan, Li-Li; Han, Gui-Hua

    2015-05-01

    By using six-qubit decoherence-free (DF) states as quantum carriers and decoy states, a robust quantum secure direct communication and authentication (QSDCA) protocol against decoherence noise is proposed. Four six-qubit DF states are used in the process of secret transmission, however only the |0‧⟩ state is prepared. The other three six-qubit DF states can be obtained by permuting the outputs of the setup for |0‧⟩. By using the |0‧⟩ state as the decoy state, the detection rate and the qubit error rate reach 81.3%, and they will not change with the noise level. The stability and security are much higher than those of the ping-pong protocol both in an ideal scenario and a decoherence noise scenario. Even if the eavesdropper measures several qubits, exploiting the coherent relationship between these qubits, she can gain one bit of secret information with probability 0.042. Project supported by the National Natural Science Foundation of China (Grant No. 61402058), the Science and Technology Support Project of Sichuan Province of China (Grant No. 2013GZX0137), the Fund for Young Persons Project of Sichuan Province of China (Grant No. 12ZB017), and the Foundation of Cyberspace Security Key Laboratory of Sichuan Higher Education Institutions, China (Grant No. szjj2014-074).

  8. Space industrialization - Education. [via communication satellites

    NASA Technical Reports Server (NTRS)

    Joels, K. M.

    1978-01-01

    The components of an educational system based on, and perhaps enhanced by, space industrialization communications technology are considered. Satellite technology has introduced a synoptic distribution system for various transmittable educational media. The cost of communications satellite distribution for educational programming has been high. It has, therefore, been proposed to utilize Space Shuttle related technology and Large Space Structures (LSS) to construct a system with a quantum advancement in communication capability and a quantum reduction in user cost. LSS for communications purposes have three basic advantages for both developed and emerging nations, including the ability to distribute signals over wide geographic areas, the reduced cost of satellite communications systems versus installation of land based systems, and the ability of a communication satellite system to create instant educational networks.

  9. Communication: An Arena of Development. Advances in Applied Developmental Psychology, Volume 19.

    ERIC Educational Resources Information Center

    Budwig, Nancy, Ed.; Uzgiris, Ina C., Ed.; Wertsch, James V., Ed.

    This volume compiles papers from a 1996 conference on communication held at Clark University (Worcester, Massachusetts). The goal of the conference was to share the work and ideas regarding the development of communication and meaning comprehension. The papers are organized into three parts, covering the organization and the origins of…

  10. Advanced Optical Technologies in NASA's Space Communication Program: Status, Challenges, and Future Plans

    NASA Technical Reports Server (NTRS)

    Pouch, John

    2004-01-01

    A goal of the NASA Space Communications Project is to enable broad coverage for high-data-rate delivery to the users by means of ground, air, and space-based assets. The NASA Enterprise need will be reviewed. A number of optical space communications technologies being developed by NASA will be described, and the prospective applications will be discussed.

  11. Observation of Quantum Fingerprinting Beating the Classical Limit

    NASA Astrophysics Data System (ADS)

    Guan, Jian-Yu; Xu, Feihu; Yin, Hua-Lei; Li, Yuan; Zhang, Wei-Jun; Chen, Si-Jing; Yang, Xiao-Yan; Li, Li; You, Li-Xing; Chen, Teng-Yun; Wang, Zhen; Zhang, Qiang; Pan, Jian-Wei

    2016-06-01

    Quantum communication has historically been at the forefront of advancements, from fundamental tests of quantum physics to utilizing the quantum-mechanical properties of physical systems for practical applications. In the field of communication complexity, quantum communication allows the advantage of an exponential reduction in the transmitted information over classical communication to accomplish distributed computational tasks. However, to date, demonstrating this advantage in a practical setting continues to be a central challenge. Here, we report a proof-of-principle experimental demonstration of a quantum fingerprinting protocol that for the first time surpasses the ultimate classical limit to transmitted information. Ultralow noise superconducting single-photon detectors and a stable fiber-based Sagnac interferometer are used to implement a quantum fingerprinting system that is capable of transmitting less information than the classical proven lower bound over 20 km standard telecom fiber for input sizes of up to 2 Gbits. The results pave the way for experimentally exploring the advanced features of quantum communication and open a new window of opportunity for research in communication complexity and testing the foundations of physics.

  12. Observation of Quantum Fingerprinting Beating the Classical Limit.

    PubMed

    Guan, Jian-Yu; Xu, Feihu; Yin, Hua-Lei; Li, Yuan; Zhang, Wei-Jun; Chen, Si-Jing; Yang, Xiao-Yan; Li, Li; You, Li-Xing; Chen, Teng-Yun; Wang, Zhen; Zhang, Qiang; Pan, Jian-Wei

    2016-06-17

    Quantum communication has historically been at the forefront of advancements, from fundamental tests of quantum physics to utilizing the quantum-mechanical properties of physical systems for practical applications. In the field of communication complexity, quantum communication allows the advantage of an exponential reduction in the transmitted information over classical communication to accomplish distributed computational tasks. However, to date, demonstrating this advantage in a practical setting continues to be a central challenge. Here, we report a proof-of-principle experimental demonstration of a quantum fingerprinting protocol that for the first time surpasses the ultimate classical limit to transmitted information. Ultralow noise superconducting single-photon detectors and a stable fiber-based Sagnac interferometer are used to implement a quantum fingerprinting system that is capable of transmitting less information than the classical proven lower bound over 20 km standard telecom fiber for input sizes of up to 2 Gbits. The results pave the way for experimentally exploring the advanced features of quantum communication and open a new window of opportunity for research in communication complexity and testing the foundations of physics. PMID:27367371

  13. Observation of Quantum Fingerprinting Beating the Classical Limit.

    PubMed

    Guan, Jian-Yu; Xu, Feihu; Yin, Hua-Lei; Li, Yuan; Zhang, Wei-Jun; Chen, Si-Jing; Yang, Xiao-Yan; Li, Li; You, Li-Xing; Chen, Teng-Yun; Wang, Zhen; Zhang, Qiang; Pan, Jian-Wei

    2016-06-17

    Quantum communication has historically been at the forefront of advancements, from fundamental tests of quantum physics to utilizing the quantum-mechanical properties of physical systems for practical applications. In the field of communication complexity, quantum communication allows the advantage of an exponential reduction in the transmitted information over classical communication to accomplish distributed computational tasks. However, to date, demonstrating this advantage in a practical setting continues to be a central challenge. Here, we report a proof-of-principle experimental demonstration of a quantum fingerprinting protocol that for the first time surpasses the ultimate classical limit to transmitted information. Ultralow noise superconducting single-photon detectors and a stable fiber-based Sagnac interferometer are used to implement a quantum fingerprinting system that is capable of transmitting less information than the classical proven lower bound over 20 km standard telecom fiber for input sizes of up to 2 Gbits. The results pave the way for experimentally exploring the advanced features of quantum communication and open a new window of opportunity for research in communication complexity and testing the foundations of physics.

  14. Advanced Communication Architectures and Technologies for Missions to the Outer Planets

    NASA Technical Reports Server (NTRS)

    Bhasin, K.; Hayden, J. L.

    2001-01-01

    Missions to the outer planets would be considerably enhanced by the implementation of a future space communication infrastructure that utilizes relay stations placed at strategic locations in the solar system. These relay stations would operate autonomously and handle remote mission command and data traffic on a prioritized demand access basis. Such a system would enhance communications from that of the current direct communications between the planet and Earth. The system would also provide high rate data communications to outer planet missions, clear communications paths during times when the sun occults the mission spacecraft as viewed from Earth, and navigational "lighthouses" for missions utilizing onboard autonomous operations. Additional information is contained in the original extended abstract.

  15. Application of the advanced communications technology satellite for teleradiology and telemedicine

    NASA Astrophysics Data System (ADS)

    Stewart, Brent K.; Carter, Stephen J.; Rowberg, Alan H.

    1995-05-01

    The authors have an in-kind grant from NASA to investigate the application of the Advanced Communications Technology Satellite (ACTS) to teleradiology and telemedicine using the JPL developed ACTS Mobile Terminal (AMT) uplink. This experiment involves the transmission of medical imagery (CT, MR, CR, US and digitized radiographs including mammograms), between the ACTS/AMT and the University of Washington. This is accomplished by locating the AMT experiment van in various locations throughout Washington state, Idaho, Montana, Oregon and Hawaii. The medical images are transmitted from the ACTS to the downlink at the NASA Lewis Research Center (LeRC) in Cleveland, Ohio, consisting of AMT equipment and the high burst rate-link evaluation terminal (HBR-LET). These images are then routed from LeRC to the University of Washington School of Medicine (UWSoM) through the Internet and public switched Integrated Serviced Digital Network (ISDN). Once images arrive in the UW Radiology Department, they are reviewed using both video monitor softcopy and laser-printed hardcopy. Compressed video teleconferencing and transmission of real-time ultrasound video between the AMT van and the UWSoM are also tested. Image quality comparisons are made using both subjective diagnostic criteria and quantitative engineering analysis. Evaluation is performed during various weather conditions (including rain to assess rain fade compensation algorithms). Compression techniques also are tested to evaluate their effects on image quality, allowing further evaluation of portable teleradiology/telemedicine at lower data rates and providing useful information for additional applications (e.g., smaller remote units, shipboard, emergency disaster, etc.). The medical images received at the UWSoM over the ACTS are directly evaluated against the original digital images. The project demonstrates that a portable satellite-land connection can provide subspecialty consultation and education for rural and remote

  16. Controlled Deterministic Secure Quantum Communication Protocol Based on Three-Particle GHZ States in X-Basis

    NASA Astrophysics Data System (ADS)

    Chang, Yan; Zhang, Shi-Bin; Yan, Li-Li; Han, Gui-Hua

    2015-03-01

    A controlled deterministic secure quantum communication (CDSQC) protocol is proposed based on three-particle GHZ state in X-basis. Only X-basis and Z1Z2X3-basis (composed of Z-basis and X-basis) measurement are required, which makes the scheme more convenient than others in practical applications. By distributing a random key between both sides of the communication and performing classical XOR operation, we realize a one-time-pad scheme, therefore our protocol achieves unconditional secure. Because only user with legitimate identity string can decrypt the secret, our protocol can resist man-in-the middle attack. The three-particle GHZ state in X-basis is used as decoy photons to detect eavesdropping. The detection rate reaches 75% per qubit. Supported by the National Natural Science Foundation of China under Grant No. 61402058, Science and Technology, Sichuan Province of China under Grant No. 2013GZX0137, Fund for Young Persons Project of Sichuan Province of China under Grant No. 12ZB017, and the Foundation of Cyberspace Security Key Laboratory of Sichuan Higher Education Institutions under Grant No. szjj2014-074

  17. Communication: Nucleation of water on ice nanograins: Size, charge, and quantum effects.

    PubMed

    Marciante, Mathieu; Calvo, Florent

    2015-05-01

    The sticking cross sections of water molecules on cold size-selected water clusters have been simulated using classical and quantum (path-integral) molecular dynamics trajectories under realistic conditions. The integrated cross sections for charged clusters show significant size effects with comparable trends as in experiments, as well as essentially no sign effect. Vibrational delocalization, although it contributes to enlarging the geometric cross sections, leads to a counter-intuitive decrease in the dynamical cross section obtained from the trajectories. These results are interpreted based on the apparent reduction in the effective interaction between the projectile and the target owing to zero-point effects.

  18. Communication: Nucleation of water on ice nanograins: Size, charge, and quantum effects

    SciTech Connect

    Marciante, Mathieu; Calvo, Florent

    2015-05-07

    The sticking cross sections of water molecules on cold size-selected water clusters have been simulated using classical and quantum (path-integral) molecular dynamics trajectories under realistic conditions. The integrated cross sections for charged clusters show significant size effects with comparable trends as in experiments, as well as essentially no sign effect. Vibrational delocalization, although it contributes to enlarging the geometric cross sections, leads to a counter-intuitive decrease in the dynamical cross section obtained from the trajectories. These results are interpreted based on the apparent reduction in the effective interaction between the projectile and the target owing to zero-point effects.

  19. Optical communication with two-photon coherent states. III - Quantum measurements realizable with photoemissive detectors

    NASA Technical Reports Server (NTRS)

    Yuen, H. P.; Shapiro, J. H.

    1980-01-01

    Homodyne detection is shown to achieve the same signal-to-noise ratio as the quantum field quadrature measurement, thus providing a receiver which realizes linear modulation TCS performance gain. The full equivalence of homodyne detection and single-quadrature field measurement is established. A heterodyne configuration which uses a TCS image-band oscillator in addition to the usual coherent state local oscillator is studied. Results are obtained by means of a representation theorem which shows that photoemissive detection realizes the photon flux density measurement.

  20. Communication: Striking dependence of diffusion kinetics in Ag–Cu nanoalloys upon composition and quantum effects

    SciTech Connect

    Asgari, Mehdi; Negreiros, Fabio R.; Sementa, Luca; Barcaro, Giovanni; Fortunelli, Alessandro; Behnejad, Hassan

    2014-07-28

    The kinetics of elemental inter-diffusion in Ag–Cu nanoalloys of 32–34 atoms around 80:20 composition is theoretically investigated by combining analytic-potential and first-principles calculations. An extremely varied behavior is found, with transformation times ranging from tens of nanoseconds to weeks at room temperature in a narrow interval of size and composition, also depending on quantum effects in magic clusters. Predictions are consistent with time-of-flight experiments and suggest their interpretation in a new light.

  1. Communication: Striking dependence of diffusion kinetics in Ag-Cu nanoalloys upon composition and quantum effects

    NASA Astrophysics Data System (ADS)

    Asgari, Mehdi; Negreiros, Fabio R.; Sementa, Luca; Barcaro, Giovanni; Behnejad, Hassan; Fortunelli, Alessandro

    2014-07-01

    The kinetics of elemental inter-diffusion in Ag-Cu nanoalloys of 32-34 atoms around 80:20 composition is theoretically investigated by combining analytic-potential and first-principles calculations. An extremely varied behavior is found, with transformation times ranging from tens of nanoseconds to weeks at room temperature in a narrow interval of size and composition, also depending on quantum effects in magic clusters. Predictions are consistent with time-of-flight experiments and suggest their interpretation in a new light.

  2. Communication: Striking dependence of diffusion kinetics in Ag-Cu nanoalloys upon composition and quantum effects.

    PubMed

    Asgari, Mehdi; Negreiros, Fabio R; Sementa, Luca; Barcaro, Giovanni; Behnejad, Hassan; Fortunelli, Alessandro

    2014-07-28

    The kinetics of elemental inter-diffusion in Ag-Cu nanoalloys of 32-34 atoms around 80:20 composition is theoretically investigated by combining analytic-potential and first-principles calculations. An extremely varied behavior is found, with transformation times ranging from tens of nanoseconds to weeks at room temperature in a narrow interval of size and composition, also depending on quantum effects in magic clusters. Predictions are consistent with time-of-flight experiments and suggest their interpretation in a new light. PMID:25084874

  3. Monolithic arrays of grating-surface-emitting diode lasers and quantum well modulators for optical communications

    NASA Technical Reports Server (NTRS)

    Carlson, N. W.; Evans, G. A.; Liew, S. K.; Kaiser, C. J.

    1990-01-01

    The electro-optic switching properties of injection-coupled coherent 2-D grating-surface-emitting laser arrays with multiple gain sections and quantum well active layers are discussed and demonstrated. Within such an array of injection-coupled grating-surface-emitting lasers, a single gain section can be operated as intra-cavity saturable loss element that can modulate the output of the entire array. Experimental results demonstrate efficient sub-nanosecond switching of high power grading-surface-emitting laser arrays by using only one gain section as an intra-cavity loss modulator.

  4. Communication and the Emergence of Collective Behavior in Living Organisms: A Quantum Approach

    PubMed Central

    Bischof, Marco; Del Giudice, Emilio

    2013-01-01

    Intermolecular interactions within living organisms have been found to occur not as individual independent events but as a part of a collective array of interconnected events. The problem of the emergence of this collective dynamics and of the correlated biocommunication therefore arises. In the present paper we review the proposals given within the paradigm of modern molecular biology and those given by some holistic approaches to biology. In recent times, the collective behavior of ensembles of microscopic units (atoms/molecules) has been addressed in the conceptual framework of Quantum Field Theory. The possibility of producing physical states where all the components of the ensemble move in unison has been recognized. In such cases, electromagnetic fields trapped within the ensemble appear. In the present paper we present a scheme based on Quantum Field Theory where molecules are able to move in phase-correlated unison among them and with a self-produced electromagnetic field. Experimental corroboration of this scheme is presented. Some consequences for future biological developments are discussed. PMID:24288611

  5. Communication: Mode specific quantum dynamics of the F + CHD3 → HF + CD3 reaction.

    PubMed

    Qi, Ji; Song, Hongwei; Yang, Minghui; Palma, Juliana; Manthe, Uwe; Guo, Hua

    2016-05-01

    The mode specific reactivity of the F + CHD3 → HF + CD3 reaction is investigated using an eight-dimensional quantum dynamical model on a recently developed ab initio based full-dimensional potential energy surface. Our results indicate prominent resonance structures at low collision energies and absence of an energy threshold in reaction probabilities. It was also found that excitation of the C-D stretching or CD3 umbrella mode has a relatively small impact on reactivity. On the other hand, the excitation of the C-H vibration (v1) in CHD3 is shown to significantly increase the reactivity, which, like several recent quasi-classical trajectory studies, is at odds with the available experimental data. Possible sources of the disagreement are discussed. PMID:27155615

  6. Communication: Mode specific quantum dynamics of the F + CHD3 → HF + CD3 reaction.

    PubMed

    Qi, Ji; Song, Hongwei; Yang, Minghui; Palma, Juliana; Manthe, Uwe; Guo, Hua

    2016-05-01

    The mode specific reactivity of the F + CHD3 → HF + CD3 reaction is investigated using an eight-dimensional quantum dynamical model on a recently developed ab initio based full-dimensional potential energy surface. Our results indicate prominent resonance structures at low collision energies and absence of an energy threshold in reaction probabilities. It was also found that excitation of the C-D stretching or CD3 umbrella mode has a relatively small impact on reactivity. On the other hand, the excitation of the C-H vibration (v1) in CHD3 is shown to significantly increase the reactivity, which, like several recent quasi-classical trajectory studies, is at odds with the available experimental data. Possible sources of the disagreement are discussed.

  7. Broadband waveguide quantum memory for entangled photons.

    PubMed

    Saglamyurek, Erhan; Sinclair, Neil; Jin, Jeongwan; Slater, Joshua A; Oblak, Daniel; Bussières, Félix; George, Mathew; Ricken, Raimund; Sohler, Wolfgang; Tittel, Wolfgang

    2011-01-27

    The reversible transfer of quantum states of light into and out of matter constitutes an important building block for future applications of quantum communication: it will allow the synchronization of quantum information, and the construction of quantum repeaters and quantum networks. Much effort has been devoted to the development of such quantum memories, the key property of which is the preservation of entanglement during storage. Here we report the reversible transfer of photon-photon entanglement into entanglement between a photon and a collective atomic excitation in a solid-state device. Towards this end, we employ a thulium-doped lithium niobate waveguide in conjunction with a photon-echo quantum memory protocol, and increase the spectral acceptance from the current maximum of 100 megahertz to 5 gigahertz. We assess the entanglement-preserving nature of our storage device through Bell inequality violations and by comparing the amount of entanglement contained in the detected photon pairs before and after the reversible transfer. These measurements show, within statistical error, a perfect mapping process. Our broadband quantum memory complements the family of robust, integrated lithium niobate devices. It simplifies frequency-matching of light with matter interfaces in advanced applications of quantum communication, bringing fully quantum-enabled networks a step closer.

  8. Advance Care Planning and Goals of Care Communication in Older Adults with Cardiovascular Disease and Multi-Morbidity.

    PubMed

    Lum, Hillary D; Sudore, Rebecca L

    2016-05-01

    This article provides an approach to advance care planning (ACP) and goals of care communication in older adults with cardiovascular disease and multi-morbidity. The goal of ACP is to ensure that the medical care patients receive is aligned with their values and preferences. In this article, the authors outline common benefits and challenges to ACP for older adults with cardiovascular disease and multimorbidity. Recognizing that these patients experience diverse disease trajectories and receive care in multiple health care settings, the authors provide practical steps for multidisciplinary teams to integrate ACP into brief clinic encounters.

  9. Advancing Partner Notification Through Electronic Communication Technology: A Review of Acceptability and Utilization Research.

    PubMed

    Pellowski, Jennifer; Mathews, Catherine; Kalichman, Moira O; Dewing, Sarah; Lurie, Mark N; Kalichman, Seth C

    2016-06-01

    A cornerstone of sexually transmitted infection (STI) prevention is the identification, tracing, and notification of sex partners of index patients. Although partner notification reduces disease burden and prevents new infections as well as reinfections, studies show that only a limited number of partners are ever notified. Electronic communication technologies, namely, the Internet, text messaging, and phone calls (i.e., e-notification), have the potential to expand partner services. We conducted a systematic review of studies that have investigated the acceptability and utility of e-notification. We identified 23 studies that met the following criteria: (a) 9 studies presented data on the acceptability of technology-based communications for contacting sex partner(s), and (b) 14 studies reported on the utilization of communication technologies for partner notification. Studies found high levels of interest in and acceptability of e-notification; however, there was little evidence for actual use of e-notification. Taken together, results suggest that electronic communications could have their greatest impact in notifying less committed partners who would otherwise be uninformed of their STI exposure. In addition, all studies to date have been conducted in resource-rich countries, although the low cost of e-notification may have its greatest impact in resource-constrained settings. Research is needed to determine the best practices for exploiting the opportunities afforded by electronic communications for expanding STI partner services.

  10. Advancing Partner Notification Through Electronic Communication Technology: A Review of Acceptability and Utilization Research

    PubMed Central

    PELLOWSKI, JENNIFER; MATHEWS, CATHERINE; KALICHMAN, MOIRA O.; DEWING, SARAH; LURIE, MARK N.; KALICHMAN, SETH C.

    2016-01-01

    A cornerstone of sexually transmitted infection (STI) prevention is the identification, tracing, and notification of sex partners of index patients. Although partner notification reduces disease burden and prevents new infections as well as reinfections, studies show that only a limited number of partners are ever notified. Electronic communication technologies, namely, the Internet, text messaging, and phone calls (i.e., e-notification), have the potential to expand partner services. We conducted a systematic review of studies that have investigated the acceptability and utility of e-notification. We identified 23 studies that met the following criteria: (a) 9 studies presented data on the acceptability of technology-based communications for contacting sex partner(s), and (b) 14 studies reported on the utilization of communication technologies for partner notification. Studies found high levels of interest in and acceptability of e-notification; however, there was little evidence for actual use of e-notification. Taken together, results suggest that electronic communications could have their greatest impact in notifying less committed partners who would otherwise be uninformed of their STI exposure. In addition, all studies to date have been conducted in resource-rich countries, although the low cost of e-notification may have its greatest impact in resource-constrained settings. Research is needed to determine the best practices for exploiting the opportunities afforded by electronic communications for expanding STI partner services. PMID:27144318

  11. Quantum photonics at telecom wavelengths based on lithium niobate waveguides

    NASA Astrophysics Data System (ADS)

    Alibart, Olivier; D'Auria, Virginia; De Micheli, Marc; Doutre, Florent; Kaiser, Florian; Labonté, Laurent; Lunghi, Tommaso; Picholle, Éric; Tanzilli, Sébastien

    2016-10-01

    Integrated optical components on lithium niobate play a major role in standard high-speed communication systems. Over the last two decades, after the birth and positioning of quantum information science, lithium niobate waveguide architectures have emerged as one of the key platforms for enabling photonics quantum technologies. Due to mature technological processes for waveguide structure integration, as well as inherent and efficient properties for nonlinear optical effects, lithium niobate devices are nowadays at the heart of many photon-pair or triplet sources, single-photon detectors, coherent wavelength-conversion interfaces, and quantum memories. Consequently, they find applications in advanced and complex quantum communication systems, where compactness, stability, efficiency, and interconnectability with other guided-wave technologies are required. In this review paper, we first introduce the material aspects of lithium niobate, and subsequently discuss all of the above mentioned quantum components, ranging from standard photon-pair sources to more complex and advanced circuits.

  12. Recent Advances in Development and Applications of the Mixed Quantum/Classical Theory for Inelastic Scattering.

    PubMed

    Babikov, Dmitri; Semenov, Alexander

    2016-01-28

    A mixed quantum/classical approach to inelastic scattering (MQCT) is developed in which the relative motion of two collision partners is treated classically, and the rotational and vibrational motion of each molecule is treated quantum mechanically. The cases of molecule + atom and molecule + molecule are considered including diatomics, symmetric-top rotors, and asymmetric-top rotor molecules. Phase information is taken into consideration, permitting calculations of elastic and inelastic, total and differential cross sections for excitation and quenching. The method is numerically efficient and intrinsically parallel. The scaling law of MQCT is favorable, which enables calculations at high collision energies and for complicated molecules. Benchmark studies are carried out for several quite different molecular systems (N2 + Na, H2 + He, CO + He, CH3 + He, H2O + He, HCOOCH3 + He, and H2 + N2) in a broad range of collision energies, which demonstrates that MQCT is a viable approach to inelastic scattering. At higher collision energies it can confidently replace the computationally expensive full-quantum calculations. At low collision energies and for low-mass systems results of MQCT are less accurate but are still reasonable. A proposal is made for blending MQCT calculations at higher energies with full-quantum calculations at low energies. PMID:26618533

  13. Recent Advances in Development and Applications of the Mixed Quantum/Classical Theory for Inelastic Scattering.

    PubMed

    Babikov, Dmitri; Semenov, Alexander

    2016-01-28

    A mixed quantum/classical approach to inelastic scattering (MQCT) is developed in which the relative motion of two collision partners is treated classically, and the rotational and vibrational motion of each molecule is treated quantum mechanically. The cases of molecule + atom and molecule + molecule are considered including diatomics, symmetric-top rotors, and asymmetric-top rotor molecules. Phase information is taken into consideration, permitting calculations of elastic and inelastic, total and differential cross sections for excitation and quenching. The method is numerically efficient and intrinsically parallel. The scaling law of MQCT is favorable, which enables calculations at high collision energies and for complicated molecules. Benchmark studies are carried out for several quite different molecular systems (N2 + Na, H2 + He, CO + He, CH3 + He, H2O + He, HCOOCH3 + He, and H2 + N2) in a broad range of collision energies, which demonstrates that MQCT is a viable approach to inelastic scattering. At higher collision energies it can confidently replace the computationally expensive full-quantum calculations. At low collision energies and for low-mass systems results of MQCT are less accurate but are still reasonable. A proposal is made for blending MQCT calculations at higher energies with full-quantum calculations at low energies.

  14. Space communication link propagation data for selected cities within the multiple beam and steerable antenna coverage areas of the advanced communications technology satellite

    NASA Technical Reports Server (NTRS)

    Manning, Robert M.

    1988-01-01

    Rain attenuation propagation data for 68 cities within the coverage area of the multiple beam and steerable antennas of the Advanced Communications Technology Satellite (ACTS) are presented. These data provide the necessary data base for purposes of communication link power budgeting and rain attenuation mitigation controller design. These propagation parameters are derived by applying the ACTS Rain Attenuation Prediction Model to these 68 locations. The propagation parameters enumerated in tabular form for each location are as follows: (1) physical description of the link and location (e.g., latitude, longitude, antenna elevation angle, etc.), link availability versus attenuation margin (also in graphical form), fading time across fade depths of 3, 5, 8, and 15 dB versus fade duration, and required fade control response time for controller availabilities of 99.999, 99.99, 99.9, and 99 percent versus sub-threshold attenuation levels. The data for these specific locations can be taken to be representative of regions near these locations.

  15. Contextuality supplies the 'magic' for quantum computation.

    PubMed

    Howard, Mark; Wallman, Joel; Veitch, Victor; Emerson, Joseph

    2014-06-19

    Quantum computers promise dramatic advantages over their classical counterparts, but the source of the power in quantum computing has remained elusive. Here we prove a remarkable equivalence between the onset of contextuality and the possibility of universal quantum computation via 'magic state' distillation, which is the leading model for experimentally realizing a fault-tolerant quantum computer. This is a conceptually satisfying link, because contextuality, which precludes a simple 'hidden variable' model of quantum mechanics, provides one of the fundamental characterizations of uniquely quantum phenomena. Furthermore, this connection suggests a unifying paradigm for the resources of quantum information: the non-locality of quantum theory is a particular kind of contextuality, and non-locality is already known to be a critical resource for achieving advantages with quantum communication. In addition to clarifying these fundamental issues, this work advances the resource framework for quantum computation, which has a number of practical applications, such as characterizing the efficiency and trade-offs between distinct theoretical and experimental schemes for achieving robust quantum computation, and putting bounds on the overhead cost for the classical simulation of quantum algorithms. PMID:24919152

  16. Contextuality supplies the 'magic' for quantum computation.

    PubMed

    Howard, Mark; Wallman, Joel; Veitch, Victor; Emerson, Joseph

    2014-06-19

    Quantum computers promise dramatic advantages over their classical counterparts, but the source of the power in quantum computing has remained elusive. Here we prove a remarkable equivalence between the onset of contextuality and the possibility of universal quantum computation via 'magic state' distillation, which is the leading model for experimentally realizing a fault-tolerant quantum computer. This is a conceptually satisfying link, because contextuality, which precludes a simple 'hidden variable' model of quantum mechanics, provides one of the fundamental characterizations of uniquely quantum phenomena. Furthermore, this connection suggests a unifying paradigm for the resources of quantum information: the non-locality of quantum theory is a particular kind of contextuality, and non-locality is already known to be a critical resource for achieving advantages with quantum communication. In addition to clarifying these fundamental issues, this work advances the resource framework for quantum computation, which has a number of practical applications, such as characterizing the efficiency and trade-offs between distinct theoretical and experimental schemes for achieving robust quantum computation, and putting bounds on the overhead cost for the classical simulation of quantum algorithms.

  17. Contextuality supplies the `magic' for quantum computation

    NASA Astrophysics Data System (ADS)

    Howard, Mark; Wallman, Joel; Veitch, Victor; Emerson, Joseph

    2014-06-01

    Quantum computers promise dramatic advantages over their classical counterparts, but the source of the power in quantum computing has remained elusive. Here we prove a remarkable equivalence between the onset of contextuality and the possibility of universal quantum computation via `magic state' distillation, which is the leading model for experimentally realizing a fault-tolerant quantum computer. This is a conceptually satisfying link, because contextuality, which precludes a simple `hidden variable' model of quantum mechanics, provides one of the fundamental characterizations of uniquely quantum phenomena. Furthermore, this connection suggests a unifying paradigm for the resources of quantum information: the non-locality of quantum theory is a particular kind of contextuality, and non-locality is already known to be a critical resource for achieving advantages with quantum communication. In addition to clarifying these fundamental issues, this work advances the resource framework for quantum computation, which has a number of practical applications, such as characterizing the efficiency and trade-offs between distinct theoretical and experimental schemes for achieving robust quantum computation, and putting bounds on the overhead cost for the classical simulation of quantum algorithms.

  18. Beyond advance directives: importance of communication skills at the end of life.

    PubMed

    Tulsky, James A

    2005-07-20

    Patients and their families struggle with myriad choices concerning medical treatments that frequently precede death. Advance directives have been proposed as a tool to facilitate end-of-life decision making, yet frequently fail to achieve this goal. In the context of the case of a man with metastatic cancer for whom an advance directive was unable to prevent a traumatic death, I review the challenges in creating and implementing advance directives, discuss factors that can affect clear decision making; including trust, uncertainty, emotion, hope, and the presence of multiple medical providers; and offer practical suggestions for physicians. Advance care planning remains a useful tool for approaching conversations with patients about the end of life. However, such planning should occur within a framework that emphasizes responding to patient and family emotions and focuses more on goals for care and less on specific treatments.

  19. Secured Optical Communications Using Quantum Entangled Two-Photon Transparency Modulation

    NASA Technical Reports Server (NTRS)

    Kojima, Jun (Inventor); Nguyen, Quang-Viet (Inventor); Lekki, John (Inventor)

    2015-01-01

    A system and method is disclosed wherein optical signals are coded in a transmitter by tuning or modulating the interbeam delay time (which modulates the fourth-order coherence) between pairs of entangled photons. The photon pairs are either absorbed or not absorbed (transparent) by an atomic or molecular fluorescer in a receiver, depending on the inter-beam delay that is introduced in the entangled photon pairs. Upon the absorption, corresponding fluorescent optical emissions follow at a certain wavelength, which are then detected by a photon detector. The advantage of the disclosed system is that it eliminates a need of a coincidence counter to realize the entanglement-based secure optical communications because the absorber acts as a coincidence counter for entangled photon pairs.

  20. Communication: Towards ab initio self-energy embedding theory in quantum chemistry

    NASA Astrophysics Data System (ADS)

    Lan, Tran Nguyen; Kananenka, Alexei A.; Zgid, Dominika

    2015-12-01

    The self-energy embedding theory (SEET), in which the active space self-energy is embedded in the self-energy obtained from a perturbative method treating the non-local correlation effects, was recently developed in our group. In SEET, the double counting problem does not appear and the accuracy can be improved either by increasing the perturbation order or by enlarging the active space. This method was first calibrated for the 2D Hubbard lattice showing promising results. In this paper, we report an extension of SEET to quantum chemical ab initio Hamiltonians for applications to molecular systems. The self-consistent second-order Green's function method is used to describe the non-local correlations, while the full configuration interaction method is carried out to capture strong correlation within the active space. Using few proof-of-concept examples, we show that SEET yields results of comparable quality to n-electron valence state second-order perturbation theory with the same active space, and furthermore, the full active space can be split into smaller active spaces without further implementation. Moreover, SEET avoids intruder states and does not require any high-order reduced density matrices. These advantages show that SEET is a promising method to describe physical and chemical properties of challenging molecules requiring large active spaces.