Organic supply chain collaboration: a case study in eight EU Countries

This study aims at contributing to a better understanding of the linkage between supply chain performance and possible performance improvement with respect to food quality and safety. Therefore, the paper addresses the question whether the level of collaborative planning and close supply chain relationships could help improve quality and safety of organic supply chains. The study was conducted as a part of the multi-disciplinary EU-wide survey of organic supply chains, carried out in 8 European countries. In this paper we report the results of the study regarding the structures and performance of six different organic supply chains in these eight European countries: milk (CH, UK), apples (DE, CH), pork (UK, NL), eggs (DE, UK), wheat (HU, IT, FR) and tomatoes (IT, NL). In depth interviews with key-informants were carried out in 2006 to investigate the structures, performance and relationships within the supply chains. Results show a low level of collaboration among various actors especially on cost and benefits sharing. Highly integrated supply chains show higher collaboration especially in the domain of Decision Synchronization. Trust and collaboration appear to be related with increased performance, while, the higher the perceived risk for quality and safety is, the higher the probability of supply chain collaboration.Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety,

Experimental implementation of encoded logical qubit operations in a perfect quantum error correcting code

Large-scale universal quantum computing requires the implementation of quantum error correction (QEC). While the implementation of QEC has already been demonstrated for quantum memories, reliable quantum computing requires also the application of nontrivial logical gate operations to the encoded qubits. Here, we present examples of such operations by implementing, in addition to the identity operation, the NOT and the Hadamard gate to a logical qubit encoded in a five qubit system that allows correction of arbitrary single qubit errors. We perform quantum process tomography of the encoded gate operations, demonstrate the successful correction of all possible single qubit errors and measure the fidelity of the encoded logical gate operations

Quantum hierarchic models for information processing

Both classical and quantum computations operate with the registers of bits. At nanometer scale the quantum fluctuations at the position of a given bit, say, a quantum dot, not only lead to the decoherence of quantum state of this bit, but also affect the quantum states of the neighboring bits, and therefore affect the state of the whole register. That is why the requirement of reliable separate access to each bit poses the limit on miniaturization, i.e, constrains the memory capacity and the speed of computation. In the present paper we suggest an algorithmic way to tackle the problem of constructing reliable and compact registers of quantum bits. We suggest to access the states of quantum register hierarchically, descending from the state of the whole register to the states of its parts. Our method is similar to quantum wavelet transform, and can be applied to information compression, quantum memory, quantum computations.Comment: 14 pages, LaTeX, 1 eps figur

Quantum integrability and nonintegrability in the spin-boson model

We study the spectral properties of a spin-boson Hamiltonian that depends on two continuous parameters $0\leq\Lambda<\infty$ (interaction strength) and $0\leq\alpha\leq\pi/2$ (integrability switch). In the classical limit this system has two distinct integrable regimes, $\alpha=0$ and $\alpha=\pi/2$. For each integrable regime we can express the quantum Hamiltonian as a function of two action operators. Their eigenvalues (multiples of $\hbar$) are the natural quantum numbers for the complete level spectrum. This functional dependence cannot be extended into the nonintegrable regime $(0<\alpha<\pi/2)$. Here level crossings are prohibited and the level spectrum is naturally described by a single (energy sorting) quantum number. In consequence, the tracking of individual eigenstates along closed paths through both regimes leads to conflicting assignments of quantum numbers. This effect is a useful and reliable indicator of quantum chaos -- a diagnostic tool that is independent of any level-statistical analysis

Quantum algorithm for simulating the dynamics of an open quantum system

In the study of open quantum systems, one typically obtains the decoherence dynamics by solving a master equation. The master equation is derived using knowledge of some basic properties of the system, the environment and their interaction: one basically needs to know the operators through which the system couples to the environment and the spectral density of the environment. For a large system, it could become prohibitively difficult to even write down the appropriate master equation, let alone solve it on a classical computer. In this paper, we present a quantum algorithm for simulating the dynamics of an open quantum system. On a quantum computer, the environment can be simulated using ancilla qubits with properly chosen single-qubit frequencies and with properly designed coupling to the system qubits. The parameters used in the simulation are easily derived from the parameters of the system+environment Hamiltonian. The algorithm is designed to simulate Markovian dynamics, but it can also be used to simulate non-Markovian dynamics provided that this dynamics can be obtained by embedding the system of interest into a larger system that obeys Markovian dynamics. We estimate the resource requirements for the algorithm. In particular, we show that for sufficiently slow decoherence a single ancilla qubit could be sufficient to represent the entire environment, in principle.Comment: 5 figures, two table

Organic Action Plans. Development, implementation and evaluation. A resource manual for the organic food and farming sector

In 2004, the European Action Plan for Organic Food and Farming was launched. Many European countries have also developed national Organic Action Plans to promote and support organic agriculture. As part of the EU funded ORGAP project (“European Action Plan of Organic Food and Farming - Development of criteria and procedures for the evaluation of the EU Action Plan for Organic Agriculture”) a toolbox to evaluate and monitor the implementation of national and European Action Plans has been developed. In order to communicate the results of this project as widely as possible, a practical manual for initiating and evaluating Organic Action Plans has been produced. This manual has been created to inspire the people, organisations and institutions involved, or with an interest, in the organic food and farming sector to engage in the initiation, review, revision and renewal of regional, national and European Organic Action Plans. The objectives of the manual are to provide: • a tool for stakeholder involvement in future Action Plan development and implementation processes at EU, national and regional level • a guide to the use of the Organic Action Plan Evaluation Toolbox (ORGAPET) developed through the project The manual summarises the key lessons learnt from more than 10 years experience of development, implementation and evaluation of Organic Action Plans throughout Europe. The Organic Action Plan Evaluation Toolbox (ORGAPET), which includes comprehensive information to support the Organic Action Plan development and evaluation process is included with the manual as a CD-ROM, and is also accessible on-line at www.orgap.org/orgapet. The ORGAP website www.orgap.org provides a further information on the project and the European and national organic action plans. Published by: Research Institute of Organic Agriculture (FiBL), Frick, Switzerland; IFOAM EU Group, Brussels Table of contents Foreword 1 1 Introduction 3 1.1 About this manual 3 1.2 Organic farming – origins, definition & principles 6 1.3 Development of organic food & farming in Europe 8 1.3.1 Organic food and farming regulation in Europe 10 1.3.2 Policy support for organic food and farming in Europe 11 2 Organic Action Plans – what are they about? 16 2.1 Why Organic Action Plans? 16 2.2 European Organic Action Plan 21 2.3 Overview of national and regional Organic Action Plans 23 3 Planning and implementing Organic Action Plans 28 3.1 Policy development 28 3.2 Defining organic sector development needs and potential 31 3.3 Defining policy goals and objectives 34 3.4 Involving stakeholders 40 3.4.1 The case for stakeholder involvement 40 3.4.2 Identifying relevant stakeholders 42 3.4.3 Participatory approaches for stakeholders involvement 44 3.5 Decision making: selecting, integrating and prioritising relevant measures 46 3.5.1 Deciding on policy instruments and action points 47 3.5.2 Priorities for action – allocating resources 50 3.6 Implementing Organic Action Plans 52 3.7 Including monitoring and evaluation of Organic Action Plans from outset 56 3.8 Managing communication 58 3.9 Development of Action Plans in countries that joined the EU in 2004 and later 59 4 Evaluating Organic Action Plans 61 4.1 Principles of evaluation 61 4.2 Conducting an evaluation 64 4.3 Evaluating Action Plan design and implementation 70 4.3.1 Evaluating programme design and implementation processes 70 4.3.2 Evaluating programme coherence 72 4.3.3 Evaluating stakeholder involvement 74 4.4 Evaluating Action Plan effects 78 4.4.1 Developing and using indicators for evaluation 78 4.5 Overall evaluation of Organic Action Plans – judging success 85 4.6 Evaluating Action Plans in countries that joined the EU in 2004 and later 89 5 Organic Action Plans – the Golden Rules 91 5.1 Key elements of Organic Action Plan development 91 5.2 The Golden rules for Organic Action Plan 93 References 96 Annex Detailed synopsis of ORGAPET 10

Geometric Effects and Computation in Spin Networks

When initially introduced, a Hamiltonian that realises perfect transfer of a quantum state was found to be analogous to an x-rotation of a large spin. In this paper we extend the analogy further to demonstrate geometric effects by performing rotations on the spin. Such effects can be used to determine properties of the chain, such as its length, in a robust manner. Alternatively, they can form the basis of a spin network quantum computer. We demonstrate a universal set of gates in such a system by both dynamical and geometrical means

Impurity spin relaxation in S=1/2 XX chains

Dynamic autocorrelations $$ (\alpha=x,z) of an isolated impurity spin in a S=1/2 XX chain are calculated. The impurity spin, defined by a local change in the nearest-neighbor coupling, is either in the bulk or at the boundary of the open-ended chain. The exact numerical calculation of the correlations employs the Jordan-Wigner mapping from spin operators to Fermi operators; effects of finite system size can be eliminated. Two distinct temperature regimes are observed in the long-time asymptotic behavior. At T=0 only power laws are present. At high T the x correlation decays exponentially (except at short times) while the z correlation still shows an asymptotic power law (different from the one at T=0) after an intermediate exponential phase. The boundary impurity correlations follow power laws at all T. The power laws for the z correlation and the boundary correlations can be deduced from the impurity-induced changes in the properties of the Jordan-Wigner fermion states.Comment: Final version to be published in Phys. Rev. B. Three references added, extended discussion of relation to previous wor

Finite Temperature and Dynamical Properties of the Random Transverse-Field Ising Spin Chain

We study numerically the paramagnetic phase of the spin-1/2 random transverse-field Ising chain, using a mapping to non-interacting fermions. We extend our earlier work, Phys. Rev. 53, 8486 (1996), to finite temperatures and to dynamical properties. Our results are consistent with the idea that there are ``Griffiths-McCoy'' singularities in the paramagnetic phase described by a continuously varying exponent $z(\delta)$, where $\delta$ measures the deviation from criticality. There are some discrepancies between the values of $z(\delta)$ obtained from different quantities, but this may be due to corrections to scaling. The average on-site time dependent correlation function decays with a power law in the paramagnetic phase, namely $\tau^{-1/z(\delta)}$, where $\tau$ is imaginary time. However, the typical value decays with a stretched exponential behavior, $\exp(-c\tau^{1/\mu})$, where $\mu$ may be related to $z(\delta)$. We also obtain results for the full probability distribution of time dependent correlation functions at different points in the paramagnetic phase.Comment: 10 pages, 14 postscript files included. The discussion of the typical time dependent correlation function has been greatly expanded. Other papers of APY are available on-line at http://schubert.ucsc.edu/pete