Quantum correlations,local interactions and error correction

Abstract

We consider the effects of local interactions upon quantum mechanically entangled systems. In particular we demonstrate that non-local correlations cannot increase through local operations on any of the subsystems, but that through the use of quantum error correction methods, correlations can be maintained. We provide two mathematical proofs that local general measurements cannot increase correlations, and also derive general conditions for quantum error correcting codes. Using these we show that local quantum error correction can preserve non-local features of entangled quantum systems. We also demonstrate these results by use of specific examples employing correlated optical cavities interacting locally with resonant atoms. By way of counter example, we also describe a mechanism by which correlations can be increased, which demonstrates the need for non-local interactions.     

Parity measurements in quantum optical metrology

We investigate the utility of parity detection to achieve Heisenberg-limited phase estimation for optical interferometry. We consider the parity detection with several input states that have been shown to exhibit sub-shot-noise interferometry with their respective detection schemes. We show that with parity detection, all these states achieve the sub-shot-noise limited phase uncertainty. Thus making the parity detection a unified detection strategy for quantum optical metrology. We also consider quantum states that are a combination of a NOON state and a dual-Fock state, which gives a great deal of freedom in the preparation of the input state, and is found to surpass the shot-noise limit.     

Identification of the domain of opportunities for a market of resources for virtual enterprise integration

In the aggressive and competitive business environment of today, enterprises are expected to achieve competitive advantages in synergy, under the format of reconfigurable global networked structures, such as the virtual enterprise (VE) organizational model, integrating the optimal resources (products, operations, services) for each of the functions that the enterprise undertakes, in order to produce a product that meets the market requirements. The literature shows that several Internet-based tools can be used to enable some activities of VE integration. However, as we demonstrate, these do not support the reconfiguration dynamics required by this organizational model. Alternatively, the authors propose the market of resources (MR) as an environment to fully support VE integration, coping with its intrinsic requirement of high reconfigurability. Based on a demonstrator developed for the MR and on cost models traducing VE integration, one for the (traditional) Internet-based tools and the other for the MR, to support an analytical simulation, the paper validates the thesis that the traditional tools cannot support agility and dynamics, presenting the MR as a VE enabler, and identifying the domain of situations where the utilization of the MR reveals increased efficiency in terms of search and selection time and cost—designated as opportunities domain.     

R curves for energy dissipative materials

This paper focuses on the theoretical simulation of fracture and stable crack growth of specimens with non-local damage. The first law of thermodynamics allows the identification or definition of appropriate crack-driving forces. The results are compared with recent ideas on defining tearing resistance for uncontained yield through the energy dissipation rate. A hypothesis regarding the conversion of mechanical into thermal energies within the non-local damage region is formulated to model the fracture behaviour of energy dissipative materials with rising crack resistance characteristics. The material's capacity to develop non-local damage is assumed to decrease with the actual damage level. This decrease relates linearly with the remaining resources of the material in dissipating energy. The hypothesis, which proposes a square root function for theoretical J-R curves, is verified by the regression analysis of experimental data regarding a European round-robin test of different steels.     

Performance implications of capability exploitation and upgrading in international joint ventures

Abstract and Key Results

Gradient projection decoding of LDPC codes and algorithmic variations

The current study proposes decoding algorithms for low density parity check codes (LDPC), which offer competitive performance-complexity trade-offs relative to some of the most efficient existing decoding techniques. Unlike existing low-complexity algorithms, which are essentially reduced complexity variations of the classical belief propagation algorithm, starting point in the developed algorithms is the gradient projections (GP) decoding technique, proposed by Kasparis and Evans (2007). The first part of this paper is concerned with the GP algorithm itself, and specifically with determining bounds on the step-size parameter, over which convergence is guaranteed. Consequently, the GP algorithm is reformulated as a message passing routine on a Tanner graph and this new formulation allows development of new low-complexity decoding routines. Simulation evaluations, performed mainly for geometry-based LDPC constructions, show that the new variations achieve similar performances and complexities per iteration to the state-of-the-art algorithms. However, the developed algorithms offer the implementation advantages that the memory-storage requirement is significantly reduced, and also that the performance and convergence speed can be finely traded-off by tuning the step-size parameter.     

Path toward net-zero buildings: a natural capital assessment framework

Building rating systems lack a methodology for assessing building’s potential for becoming self-sufficient by using local resources. There is a gap in the literature for linking natural capital assessment and net-zero buildings. This paper presents a methodology for assessment of natural capital to achieve net-zero targets in buildings. The developed methodology is demonstrated through a Living Building Challenge^® registered building. The contribution of water, energy and building materials is discussed, and various scenarios are evaluated on how the building can become net-zero over its life cycle by using local natural resources. Results show that the building can generate 100% of its energy and 92% of its water on-site and can become net-zero with the help of materials recycling and off-site carbon offset program.     

A gradient thermodynamic theory of self-organization

Summary In this paper we present a gradient theory of internal variables in a thermodynamic context of the Gibbs free energy density ø. A fundamental point of the theory is that ø is a function of three different classes of internal variables: (a) tensorial dissipative and local; (b) vectorial dissipative and non-local and (c) vectorialinviscid and non-local. These classes obey different types of evolution equations. The ones pertaining to the non-local variables are partial differential equations of the diffusion-reaction type. We associate the inviscid non-local variables with energy release mechanisms and show that they lead to patterned deformation, otherwise known as self-organization. We conclude by giving a solution to the problem of a flat plate in nominal axial tension and derive various types of deformation patterns that result from small but unavoidable experimental deviations from this loading.     

3D-FE-Analysis of CT-specimens including viscoplastic material behavior and nonlocal damage

In order to describe the time-dependent inelastic behavior of steel structures up to failure, a material model is developed within the framework of thermodynamics considering viscoplastic material behavior, isotropic hardening, softening, and isotropic ductile damage. Since softening and damage lead to localization of deformations, the model is extended by a non-local implicit gradient formulation. An additional gradient equation is formulated for the local damage variable in order to achieve results independent of the finite-element discretization. The approach is verified by 3D-structural analysis of CT-specimens.     

Isomorphic Pressures, Peripheral Product Attributes and Emerging Market Firm Export Performance

• Drawing upon the neo-institutional theory of mimetic isomorphism and the concept of the extended product, we identify and empirically evaluate two potential product strategies that emerging market firms (EMFs) may use to improve their export performance while also addressing the financial, managerial expertise, and international experience limitations that they frequently face.
• Hierarchical regression is used to test our proposed peripheral product adaptation strategies on a unique dataset of 106 Chinese and Romanian exporters.
• We find that EMFs that change either of two visible peripheral product attributes (the brand name or the packaging) to conform to local market norms, on average, are more satisfied with their export performance than those that pursue other strategies. Our results also suggest that changing the brand name to conform to local market norms has more than twice the impact on EMF performance than does changing the packaging.
• Consistent with the tenets of neo-institutional theory, EMFs managers may be able to improve their firms’ export performance by changing the peripheral attributes of their products to conform to local market norms.

     

Structural stability of travelling waves in an integrodifferential equation

In this article, we study the structural stability of travelling waves of an integrodifferential equation, which can be viewed as the non-local analogon of the reaction-diffusion equation [udot] = u_xx + f(u). More precisely, we are interested in the question whether a travelling wave solution persists under small perturbations of the equation. Since the travelling wave equation is a functional differential equation of mixed type, a deeper understanding of the intersection of stable and unstable manifold of the steady state in mixed type equations turns out to be crucial. As one of the main results, we prove the existence of stable and unstable manifolds for general functional differential equations. We apply our results to the one-dimensional equation of elasticity with non-local energy. In particular, we prove that a travelling wave is structural stable if and only if the underlying shock wave is compressive.     

A closed formula for local sensitivity analysis in mathematical programming

This article introduces a method for local sensitivity analysis of practical interest. A theorem is given that provides a general and neat manner to obtain all sensitivities of a general nonlinear programming problem (around a local minimum) with respect to any parameter irrespective of it being a right-hand side, objective function or constraint constant. The method is based on the well-known duality property of mathematical programming, which states that the partial derivatives of the primal objective function with respect to the constraints' right-hand side parameters are the optimal values of the dual problem variables. For the parameters or data for which sensitivities are sought to appear on the right-hand side, they are converted into artificial variables and set to their actual values, thus obtaining the desired constraints. If the problem is degenerated and partial derivatives do not exist, the method also permits obtaining the right, left, and also directional derivatives, if they exist. In addition to its general applicability, the method is also computationally inexpensive because the necessary information becomes available without extra calculations. Moreover, analytical relations among sensitivities, locally valid, are straightforwardly obtained. It is also shown how the roles of the objective function and any of the active constraints (equality or inequality) can be exchanged leading to equivalent optimization problems. This permits obtaining the sensitivities of any constraint with respect to the parameters without the need of repeating the calculations. The method is illustrated by its application to two examples, one degenerated and the other one of a competitive market.     

Assessing the resource usage in scheduling with incompatibilities

In the field of resource constrained scheduling, the papers in the literature are mainly focused on minimizing the maximum completion time of a set of tasks to be carried out, paying attention to respecting the maximum simultaneous availability of each resource type in the system. This work, instead, considers the issues of balancing the resource usage and minimizing the peak of the resources allocated each time in the schedule, while keeping the makespan low. To this aim we propose a local search algorithm which acts as a multi start greedy heuristic. Extensive experiments on various randomly generated test instances are provided. Furthermore, we present a comparison with lower bounds and known heuristics. Correspondence to: Massimiliano CaramiaWe wish to thank the anonymous referees for their useful comments which have led to this improved version of the paper.     

Enriched machining feature-based reasoning for generic machining process sequencing

This paper presents an enriched machining feature (EMF)-based reasoning approach to generic machining process sequencing for distributed process planning (DPP). An EMF is represented by combining its machining volume with surface, geometric and volume features, as well as other technological information needed to machine the feature. The information embedded in the EMF is retrieved progressively for machining sequence generation. Following an introduction of EMF and its representation scheme, the problems in determining machine-independent feature groups (set-ups) in DPP and their machining sequences to be followed for a given part are investigated. Based on the EMF concept, five reasoning rules are formulated and the algorithms developed. As the set-ups and sequences are generated based on manufacturing constraints and datum references but separated from specific resources, they are generic and applicable to machine tools with varying configurations and capabilities. This approach is further validated through a case study.     

Non-local quantum gates: A cavity-quantum-electrodynamics implementation

Abstract

The problems related to the management of large quantum registers could be handled in the context of distributed quantum computation: unitary non-local transformations among spatially separated local processors are realized performing local unitary transformations and exchanging classical communication. In this paper, a scheme is proposed for the implementation of universal non-local quantum gates such as a controlled NOT (CNOT) and a controlled quantum phase gate (CQPG). The system chosen for their physical implementation is a cavity-quantum-electrodynamics (CQED) system formed by two spatially separated microwave cavities and two trapped Rydberg atoms. The procedures to follow for the realization of each step necessary to perform a specific non-local operation are described.     

Growth of De Alio and De Novo firms in the new and renewable energy industry

Firms entering new markets are either de alio, with business experience in other areas, or de novo, without such experience. De alio firms enter markets in advantageous situations, while de novo firms enter markets with innovation capabilities. This study determines whether de alio or de novo firms achieve faster sales growth as well as the duration of their growth when they enter the new and renewable energy industry. Panel data for global companies that entered the new and renewable energy industry after the 1990s show that de alio firms achieved higher growth rate than did de novo firms in the initial stages, but that entry type’s contribution to sales growth gradually decreased and disappeared four years after entrance. The results indicate that accumulated resources and new entrants’ former experiences in other industries have positive effects, contributing to initial success after market entry for a limited time. This finding suggests that firms improve the R&Cs (resources and capabilities) that are appropriate to their new environments for sustainable development.     

X-ray Absorption Spectroscopy Probing the Local Structure Changes at the Tetragonal-Orthorhombic Transition in LnOFeAs Pnictides

We report both measurements and local density approximation calculations of the Fe K-edge X-ray absorption near edge (XANES) spectra of LnOFeAs high T _c superconductors. Calculations based on the local structure centered at the Fe site obtained by crystallographic investigations reproduce observed changes in the spectra under switching of the crystal structure from the tetragonal to the orthorhombic striped phase. Although the local structure changes are very small, their effect is revealed by clear signatures at the absorption edge, indicating the variations of the Fe local unoccupied electronic states. Calculated Fe density of states that do not include spin ordering in the orthorhombic phase do not show a significant modification, implying that the striped spin ordering in the orthorhombic phase is necessary to describe its electronic properties.     

Nanostructures,Entanglement and the Physics of Quantum Control

Abstract

Nanostructures might be viewed as solid-state approximations to SU(N) networks, the nodes of which would, in simplest form, be analogous to elementary spins. Owing to interactions with an external light field and coupling between the local nodes these networks allow for single- and multiple-node coherence (entanglement), despite damping. By means of stochastic simulations we demonstrate how such a ‘quantum machinery’ embedded in a qualified environment would look like in terms of measurement protocols. These protocols give evidence for the underlying complex behaviour of the network, a complexity which is based on the non-local information contained in the entanglement and which would not be present in the ‘classical limit’ of using local information only.     

侗族油茶饮食文化的产品服务系统设计

目的 以侗族油茶的饮食文化为切入点,以乡村振兴背景下的文化旅游发展为目标,探索针对特色饮食文化资源的产品服务系统设计的方法。方法 将饮食文化作为乡村文化资源的代表,基于主观幸福感理论分析饮食行为中的幸福感三层次,结合产品服务系统设计（PSSD）的理论与方法,并通过设计“侗心油茶坊”的产品服务系统作为实证研究,对文化旅游中当地人与游客在饮食体验上的幸福感设计的方法和路线进行分析。结论 在文化旅游中,通过对本土的文化资源、自然资源与人力资源进行充分调动,将物质资源转化为符合市场需求的有形产品,而非物质资源转化融入服务与体验,并通过产业升级与创新,使当地人在文化实践中树立文化自信,实现经济创收,提升他们在乡村生活中的主观幸福感;同时,通过给游客提供良好的文化旅游服务,使其获得文化熏陶与精神感染,提升他们在旅途中的主观幸福感。     

Superconductivity in Mesoscopic Metal Particles

Recently, it has been possible to construct single-electron transistors to study electronic properties, including superconductivity, in metallic grains of nanometer size. Among several theoretical results are suppression of superconductivity with decreasing grain size and parity effect (i.e., dependence on the parity of the number of electrons on the grain). We study how these results are affected by degeneracy of energy levels. In addition to the time-reversal symmetry, for certain energy spectra and more generally for lattice symmetries, energy levels degenerate strongly near the Fermi energy. For a parabolic dispersion, degeneracy d is of the order of k _F L, whereas the typical distance between the levels is of the order of _F/(k _F L)², where k _F and _F are the Fermi wave-vector and energy, respectively, and L is the particle size. First, using an exact solution method for BCS Hamiltonian with finite number of energy levels, for the well-studied nondegenerate case we find a new feature. In that case, parity effect exhibits a minimum instead of a monotonic behavior. For d-fold degenerate states, we find that the ratio of two successive parity effect parameters _p is nearly 1 + 1/d. Our numeric solutions for the exact ground-state energy of negative U Hubbard model on a cubic cluster also give very similar results. Hence we conclude that parity effect is a general property of small Fermi systems with attractive interaction, and it is closely related to degeneracy of energy levels.