Real time demonstration of high bitrate quantum random number generation with coherent laser light

We present a random number generation scheme that uses broadband measurements of the vacuum field contained in the radio-frequency sidebands of a single-mode laser. Even though the measurements may contain technical noise, we show that suitable algorithms can transform the digitized photocurrents into a string of random numbers that can be made arbitrarily correlated with a subset of the quantum fluctuations (high quantum correlation regime) or arbitrarily immune to environmental fluctuations (high environmental immunity). We demonstrate up to 2 Gbps of real time random number generation that were verified using standard randomness tests

A Continuum Model for Soil-Pile-Structure Interactions Under Earthquake Excitation

An exact analytical method for the interaction analysis of a fully coupled soil-pile-structure system under seismic excitation is investigated in this paper. Only horizontal shaking induced by harmonic SH waves was considered. The soil mass, pile and building were all considered as elastic with hysteretic type damping. Geometrically, the soil is modeled as an elastic isotropic homogeneous continuum, and both pile and structures are simplified as beam models. The structure and piles are coupled through a rigid foundation at the ground level. Buildings of various heights in Hong Kong designed to withstand wind load were analyzed using the present model. Only the shaking at the ground level is considered in this study. It was discovered that the maximum shaking of the piled-structures at ground level is generally larger than that of a free field ground shaking except near the first natural frequency of the coupled soil-pile-structure system. This first resonant frequency depends strongly on the natural frequency of the structure

Theoretical Analysis of an Ideal Noiseless Linear Amplifier for Einstein-Podolsky-Rosen Entanglement Distillation

We study the operational regime of a noiseless linear amplifier based on quantum scissors that can nondeterministically amplify the one photon component of a quantum state with weak excitation. It has been shown that an arbitrarily large quantum state can be amplified by first splitting it into weak excitation states using a network of beamsplitters. The output states of the network can then be coherently recombined. In this paper, we analyse the performance of such a device for distilling entanglement after transmission through a lossy quantum channel, and look at two measures to determine the efficacy of the noiseless linear amplifier. The measures used are the amount of entanglement achievable and the final purity of the output amplified entangled state. We study the performances of both a single and a two-element noiseless linear amplifier for amplifying weakly excited states. Practically, we show that it may be advantageous to work with a limited number of stages.Comment: 10 pages, 11 figure

Matrix product solution to an inhomogeneous multi-species TASEP

We study a multi-species exclusion process with inhomogeneous hopping rates. This model is equivalent to a Markov chain on the symmetric group that corresponds to a random walk in the affine braid arrangement. We find a matrix product representation for the stationary state of this model. We also show that it is equivalent to a graphical construction proposed by Ayyer and Linusson, which generalizes Ferrari and Martin's construction

Flavor Symmetry L_mu - L_tau and quasi-degenerate Neutrinos

Current data implies three simple forms of the neutrino mass matrix, each corresponding to the conservation of a non-standard lepton charge. While models based on L_e and L_e - L_mu - L_tau are well-known, little attention has been paid to L_mu - L_tau. A low energy mass matrix conserving L_mu - L_tau implies quasi-degenerate light neutrinos. Moreover, it is mu-tau symmetric and therefore (in contrast to L_e and L_e - L_mu - L_tau) automatically predicts maximal atmospheric neutrino mixing and zero U_{e3}. A see-saw model based on L_mu - L_tau is investigated and testable predictions for the neutrino mixing observables are given. Renormalization group running below and in between the see-saw scales is taken into account in our analysis, both numerically and analytically.Comment: 15 pages, 2 figures. Prepared for 5th International Conference on Nonaccelerator New Physics (NANP 05), Dubna, Russia, 20-25 Jun 200

Enhancing the Financial Returns of R&D Investments through Operations Management

Although much research has been carried out to examine various contextual issues and moderating factors for successful R&D investments, very little research has been conducted to explore the role of a firm’s operational and process characteristics. In this study, we explore how firms could possibly enhance the financial returns of R&D investments through quality management, using Six Sigma implementation as an example, and efficiency improvement, using the stochastic frontier estimation of relative efficiency as a proxy. Based on data from 468 manufacturing firms in the U.S. over the period 2007-2014, we construct a dynamic panel data model to capture the effects of R&D investments on firms’ financial returns in terms of Tobin’s q. Using the system generalized method of moments estimator, our results indicate that the financial returns of R&D investments are significantly enhanced when firms adopt Six Sigma and improve efficiency in operations. Our additional analyses further suggest that such an enhancement effect through quality and efficiency improvements is more pronounced under high operational complexity as approximated by labor intensity and geographical diversity. Instead of considering innovation activities and process management as contradictory functions, we show that quality and efficiency improvements indeed support firms’ R&D investments, leading to higher financial returns

Exploiting FPGA-aware merging of custom instructions for runtime reconfiguration

Runtime reconfiguration is a promising solution for reducing hardware cost in embedded systems, without compromising on performance. We present a framework that aims to increase the performance benefits of reconfigurable processors that support full or partial runtime reconfiguration. The proposed framework achieves this by: (1) providing a means for choosing suitable custom instruction selection heuristics, (2) leveraging FPGA-aware merging of custom instructions to maximize the reconfigurable logic block utilization in each configuration, and (3) incorporating a hierarchical loop partitioning strategy to reduce runtime reconfiguration overhead. We show that the performance gain can be improved by employing suitable custom instruction selection heuristics that, in turn, depend on the reconfigurable resource constraints and the merging factor (extent to which the selected custom instructions can be merged). The hierarchical loop partitioning strategy leads to an average performance gain of over 31% and 46% for full and partial runtime reconfiguration, respectively. Performance gain can be further increased to over 52% and 70% for full and partial runtime reconfiguration, respectively, by exploiting FPGA-aware merging of custom instructions.</jats:p