Nature-Inspired Interconnects for Self-Assembled Large-Scale Network-on-Chip Designs

Future nano-scale electronics built up from an Avogadro number of components needs efficient, highly scalable, and robust means of communication in order to be competitive with traditional silicon approaches. In recent years, the Networks-on-Chip (NoC) paradigm emerged as a promising solution to interconnect challenges in silicon-based electronics. Current NoC architectures are either highly regular or fully customized, both of which represent implausible assumptions for emerging bottom-up self-assembled molecular electronics that are generally assumed to have a high degree of irregularity and imperfection. Here, we pragmatically and experimentally investigate important design trade-offs and properties of an irregular, abstract, yet physically plausible 3D small-world interconnect fabric that is inspired by modern network-on-chip paradigms. We vary the framework's key parameters, such as the connectivity, the number of switch nodes, the distribution of long- versus short-range connections, and measure the network's relevant communication characteristics. We further explore the robustness against link failures and the ability and efficiency to solve a simple toy problem, the synchronization task. The results confirm that (1) computation in irregular assemblies is a promising and disruptive computing paradigm for self-assembled nano-scale electronics and (2) that 3D small-world interconnect fabrics with a power-law decaying distribution of shortcut lengths are physically plausible and have major advantages over local 2D and 3D regular topologies

Corrigendum: Effects of a 3-week inpatient multidisciplinary body weight reduction program on body composition and physical capabilities in adolescents and adults with obesity

A correction has been made to Funding. The correct Funding statement is: “Research funded by the Italian Ministry of Health.” The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated

Increased pump acceptance bandwidth in spontaneous parametric downconversion process using Bragg reflection waveguides

In this paper we show that by suitably tailoring the dispersion characteristics of a Bragg reflection waveguide (BRW) mode, it is possible to achieve efficient photon pair generation over a large pump bandwidth while maintaining narrow signal bandwidth. The structure proposed consists of a high index core BRW with a periodically poled GaN core and periodically stratified cladding made up of alternate layers of $Al_{0.02}Ga_{0.98}N$ and $Al_{0.45}Ga_{0.55}N$. Such photon-pair generators should find applications in realizing compact and stable sources for quantum information processing.Comment: 6 pages, 5 figure

Orbiting Resonances and Bound States in Molecular Scattering

A family of orbiting resonances in molecular scattering is globally described by using a single pole moving in the complex angular momentum plane. The extrapolation of this pole at negative energies gives the location of the bound states. Then a single pole trajectory, that connects a rotational band of bound states and orbiting resonances, is obtained. These complex angular momentum singularities are derived through a geometrical theory of the orbiting. The downward crossing of the phase-shifts through pi/2, due to the repulsive region of the molecular potential, is estimated by using a simple hard-core model. Some remarks about the difference between diffracted rays and orbiting are also given.Comment: 18 pages, 3 figures, to appear in Physical Review

Artefacts and <A2> power corrections : revisiting the MOM Z_psi and Z_V

We extract the power corrections due to the A^2 condensate in the overlap quark propagator (vector part of the inverse propagator Z_psi). The results are consistent with the previous gluon analysis. The role of artefacts is extensively discussed.Comment: 33 pages, 5 figure

Acute respiratory muscle unloading improves time-to-exhaustion during moderate- and heavy-intensity cycling in obese adolescent males

Obesity significantly impairs breathing during exercise. The aim was to determine, in male obese adolescents (OB), the effects of acute respiratory muscle unloading, obtained by switching the inspired gas from ambient air (AIR) to a normoxic helium + oxygen gas mixture (HeO2) (AIR \u2192 HeO2) during moderate [below gas exchange threshold (GET)] and heavy [above GET] constant work rate cycling. Ten OB [age 16.0 \ub1 2.0\ua0years (mean \ub1 SD); body mass index (BMI) 38.9 \ub1 6.1\ua0kg/m2] and ten normal-weight age-matched controls (CTRL) inspired AIR for the entire exercise task, or underwent AIR \u2192 HeO2 when they were approaching volitional exhaustion. In OB time to exhaustion (TTE) significantly increased in AIR \u2192 HeO2 vs. AIR during moderate [1524 \ub1 480\ua0s vs. 1308 \ub1 408 (P = 0.024)] and during heavy [570 \ub1 306\ua0s vs. 408 \ub1 150 (P = 0.0154)] exercise. During moderate exercise all CTRL completed the 40-min task. During heavy exercise no significant differences were observed in CTRL for TTE (582 \ub1 348\ua0s [AIR \u2192 HeO2] vs. 588 \ub1 252 [AIR]). In OB, but not in CTRL, acute unloading of respiratory muscles increased TTE during both moderate- and heavy-exercise. In OB, but not in CTRL, respiratory factors limit exercise tolerance during both moderate and heavy exercise

Performance Driven Reliable Link Design for Networks on Chips

With decreasing feature size of transistors, the interconnect wire delay is becoming a major bottleneck in current Systems on Chips (SoCs). Another effect of shrinking feature size is that the wires are becoming unrealable as they are increasingly susceptible to various noise sources such as cross-talk, coupling noise, soft errors etc. Increasing importance of wire delay an reliability has lead to a communication centric design approach, Networks in Chip (NoC), for building complex SoCs. Current NoC communication design methodologies are based on conservative design approaches and consider worst case operating conditions for link design, resulting in lare latency penalty for data transmission. In order to substantially descrease the link delay and therby increase system performance an aggressive design approach is needed. In this work we present Terror, timing error tolerant communication system, for aggressively design the links of NoCs. In our methodology, instead of avoiding timing errors by worst-case design, we do aggressive design by tolerating timing errors. Simulation results show large latency savings (up to 35%) for the Terror based system compared to traditional design methodology

apeNEXT: A multi-TFlops Computer for Simulations in Lattice Gauge Theory

We present the APE (Array Processor Experiment) project for the development of dedicated parallel computers for numerical simulations in lattice gauge theories. While APEmille is a production machine in today's physics simulations at various sites in Europe, a new machine, apeNEXT, is currently being developed to provide multi-Tflops computing performance. Like previous APE machines, the new supercomputer is largely custom designed and specifically optimized for simulations of Lattice QCD.Comment: Poster at the XXIII Physics in Collisions Conference (PIC03), Zeuthen, Germany, June 2003, 3 pages, Latex. PSN FRAP15. Replaced for adding forgotten autho

Three-body interactions with cold polar molecules

We show that polar molecules driven by microwave fields give naturally rise to strong three-body interactions, while the two-particle interaction can be independently controlled and even switched off. The derivation of these effective interaction potentials is based on a microscopic understanding of the underlying molecular physics, and follows from a well controlled and systematic expansion into many-body interaction terms. For molecules trapped in an optical lattice, we show that these interaction potentials give rise to Hubbard models with strong nearest-neighbor two-body and three-body interaction. As an illustration, we study the one-dimensional Bose-Hubbard model with dominant three-body interaction and derive its phase diagram.Comment: 8 pages, 4 figure

GHz QKD at telecom wavelengths using up-conversion detectors

We have developed a hybrid single photon detection scheme for telecom wavelengths based on nonlinear sum-frequency generation and silicon single-photon avalanche diodes (SPADs). The SPAD devices employed have been designed to have very narrow temporal response, i.e. low jitter, which we can exploit for increasing the allowable bit rate for quantum key distribution. The wavelength conversion is obtained using periodically poled Lithium niobate waveguides (W/Gs). The inherently high efficiency of these W/Gs allows us to use a continuous wave laser to seed the nonlinear conversion so as to have a continuous detection scheme. We also present a 1.27GHz qubit repetition rate, one-way phase encoding, quantum key distribution experiment operating at telecom wavelengths that takes advantage of this detection scheme. The proof of principle experiment shows a system capable of MHz raw count rates with a QBER less than 2% and estimated secure key rates greater than 100 kbit/s over 25 km.Comment: 12 pages, 7 figure