Entanglement estimation in non-optimal qubit states

In the last years, a relationship has been established between the quantum Fisher information (QFI) and quantum entanglement. In the case of two-qubit systems, all pure entangled states can be made useful for sub-shot-noise interferometry while their QFI meets a necessary and sufficient condition [1]. In M-qubit systems, the QFI provides just a sufficient condition in the task of detecting the degree of entanglement of a generic state [2]. In our work, we show analytically that, for a large class of one-parameter non-optimal two-qubit states, the maximally entangled states are associated with stationary points of the QFI, as a function of such parameter. We show, via numerical simulations, that this scenario is maintained for the generalisation of this class of states to a generic M-qubit system. Furthermore, we suggest a scheme for an interferometer able to detect the entanglement in a large class of two-spin states.Comment: 7 pages, 7 figure

Opening the system to the environment: new theories and tools in classical and quantum settings

The thesis is organized as follows. Section 2 is a first, unconventional, approach to the topic of EPs. Having grown interest in the topic of combinatorics and graph theory, I wanted to exploit its very abstract and mathematical tools to reinterpret something very physical, that is, the EPs in wave scattering. To do this, I build the interpretation of scattering events from a graph theory perspective and show how EPs can be understood within this interpretation. In Section 3, I move from a completely classical treatment to a purely quantum one. In this section, I consider two quantum resonators coupled to two baths and study their dynamics with local and global master equations. Here, the EPs are the key physical features used as a witness of validity of the master equation. Choosing the wrong master equation in the regime of interest can indeed mask physical and fundamental features of the system. In Section 4, there are no EPs. However I transition towards a classical/quantum framework via the topic of open systems. My main contribution in this work is the classical stochastic treatment and simulation of a spin coupled to a bath. In this work, I show how a natural quantum--to--classical transition occurs at all coupling strengths when certain limits of spin length are taken. As a key result, I also show how the coupling to the environment in this stochastic framework induces a classical counterpart to quantum coherences in equilibrium. After this last topic, in Section 5, I briefly present the key features of the code I built (and later extended) for the latter project. This, in the form of a Julia registry package named SpiDy.jl, has seen further applications in branching projects and allows for further exploration of the theoretical framework. Finally, I conclude with a discussion section (see Sec. 5) where I recap the different conclusions gathered in the previous sections and propose several possible directions.Engineering and Physical Sciences Research Council (EPSRC

Competence evaluation processes in adult education

Professionals in the adult education field regularly have to deal with evaluating the competences of diverse populations at various stages in their work process: first when analysing people\u27s needs, next when designing training programmes to meet these needs (translating competence needs into training needs), and finally when assessing whether the training helped individuals acquire the expected competences. [...] This chapter will examine a number of aspects of the process of competence evaluation. First, it will outline various elements to help identify the origins and subsequent development of competence evaluation activities. Secondly, it will explain the conceptual and practical difficulties associated with evaluating competences, describing the most commonly used tools and methods. Finally, the author will look at how competences are evaluated in various European countries, concluding with a number of examples of schemes currently in use. (DIPF/Orig.

Same-sex marriage and same-sex adoption: Socio-political context of the rights of gay and lesbian people in Belgium

Belgium is considered as being on the forefront of a number of rights for lesbian, gay, bisexual and transgender people (LGBT). In the 1990s, the law on legal cohabitation made it possible for same-sex couples to draw up cohabitation contracts. Belgium then became the second country in Europe to authorise marriage between same-sex partners in 2003, as well as opening up access to parenthood to LGBT people, in 2006. In addition, the Government has launched several programmes to fight against homophobia in schools and in society in general. The aim of this paper is to describe the changes that have taken place in Belgian legislation from traditional family law through to the opening up of marriage and parenthood to homosexual couples, analysing the arguments which have been put forward in support and against it, as well as the potential rational behind shared agendas. It will also describe the emergence of the LGBT movement in Belgium, the various non-governmental organisations which are active in the country and the role they play. An overview of current events will be presented (changes in the number of marriages, divorces and adoptions in Belgium). Finally, the paper will discuss the reactions of Belgian society and the challenges which LGBT people living in Belgium still have to face. In this way, we aim to contribute towards an overview of the current socio-political context in Belgium, in order to better understanding the processes at work in a country which wants to be seen as gay-friendly

Entanglement distance for an arbitrary state of M qubits

We propose a measure of entanglement that can be computed for any pure state of an $M$-qubit system. The entanglement measure has the form of a distance that we derive from an adapted application of the Fubini-Study metric. This measure is invariant under local unitary transformations and defined as trace of a suitable metric that we derive, the entanglement metric $\tilde{g}$. Furthermore, the analysis of the eigenvalues of $\tilde{g}$ gives information about the robustness of entanglement.Comment: 6 pages, 5 figure

Stiction Quantification: A Robust Methodology for Valve Monitoring and Maintenance Scheduling

Valve stiction is one of the most common causes of poor performance in control loops. This paper presents a procedure which allows stiction quantification. The technique permits one to estimate the unknown real stem position, and moreover, it does not need any process knowledge and requires only the data normally registered in industrial plants. It is pointed out that the real problem consists of the lack of knowledge about the true value of stiction. A general methodology is proposed to discard data for which quantification is very likely to give wrong indications and to restrict its application to appropriate cases. Simulations show that several sources of perturbations can be eliminated, thus improving the reliability of stiction evaluation. Results are confirmed by application to industrial data: a significant number of valves are analyzed for repeated acquisitions before and after plant shutdown. The proposed procedure seems to be a valid methodology to monitor valve stiction and to schedule and check valve maintenance

The IGS-ETS in Bacillus (Insecta Phasmida): molecular characterization and the relevance of sex in ribosomal DNA evolution

<p>Abstract</p> <p>Background</p> <p>DNA encoding for ribosomal RNA (rDNA) is arranged in tandemly-repeated subunits, each containing ribosomal genes and non-coding spacers. Because tandemly-repeated, rDNA evolves under a balanced influence of selection and "concerted evolution", which homogenizes rDNA variants over the genome (through genomic turnover mechanisms) and the population (through sexuality).</p> <p>Results</p> <p>In this paper we analyzed the IGS-ETS of the automictic parthenogen <it>Bacillus atticus </it>and the bisexual <it>B. grandii</it>, two closely related stick-insect species. Both species share the same IGS-ETS structure and sequence, including a peculiar head-to-tail array of putative transcription enhancers, here named <it>Bag530</it>. Sequence variability of both IGS-ETS and <it>Bag530 </it>evidenced a neat geographic and subspecific clustering in <it>B. grandii</it>, while <it>B. atticus </it>shows a little but evident geographic structure. This was an unexpected result, since the parthenogen <it>B. atticus </it>should lack sequence fixation through sexuality. In <it>B. atticus </it>a new variant might spread in a given geographic area through colonization by an all-female clone, but we cannot discard the hypothesis that <it>B. atticus </it>was actually a bisexual taxon in that area at the time the new variant appeared. Moreover, a gene conversion event between two <it>Bag530 </it>variants of <it>B. grandii benazzii </it>and <it>B. grandii maretimi </it>suggested that rRNA might evolve according to the so-called "library hypothesis" model, through differential amplification of rDNA variants in different taxa.</p> <p>Conclusion</p> <p>On the whole, <it>Bacillus </it>rDNA evolution appears to be under a complex array of interacting mechanisms: homogenization may be achieved through genomic turnover that stabilizes DNA-binding protein interactions but, simultaneously, new sequence variants can be adopted, either by direct appearance of newly mutated repeats, or by competition among repeats, so that both DNA-binding proteins and repeat variants drive each other's evolution. All this, coupled with chromosome reshuffling due to sexuality (when present), might drive a quick fixation of new rDNA variants in the populations.</p

Quenched invariance principle for biased random walks in random conductances in the sub-ballistic regime

We consider a biased random walk in positive random conductances on $\mathbb{Z}^d$ for $d\geq 5$. In the sub-ballistic regime, we prove the quenched convergence of the properly rescaled random walk towards a Fractional Kinetics.Comment: 59 pages, 8 figures. Modifications in Theorem 1.2, Section 3-4-