461 research outputs found

    ‘Roving Vultures’. Television News and the Outbreak of the Troubles in Northern Ireland

    Get PDF
    Almost exactly fifty years ago, an illegal Civil Rights march in Londonderry in Northern Ireland was broken up by the local police force, the Royal Ulster Constabulary. Hitherto, Northern Ireland, although a constituent part of the UK kingdom, was an unknown quantity for most British people, who knew or cared little about its endemic sectarian problems, and its one-sided and discriminatory system of government. Had the march taken place in 1958 rather than 1968, it very likely would be remained only an item of local interest and controversy. However, the presence in 1968 of three television crews, who recorded what transpired, meant that the problems of the Province were cruelly exposed, leading to a spiral of violence known as ‘the Troubles’ which would cost the lives of some 3,600 people in the succeeding decades

    ‘No Pope Here.’ Britain, the Vatican, the IRA and the Papal Visit to Ireland, September 1979

    Get PDF
    It is often assumed, particularly by outsiders, that the conflict in Northern Ireland, known euphemistically as ‘the Troubles’, in which some 3,600 people lost their lives, was an atavistic throwback to Europe’s religious wars of earlier centuries. In 1979, by which time some 2,000 people had already been killed in the Troubles, Pope John Paul II proposed to pay a visit to Ireland, and perhaps to cross the border into Ulster’s sectarian cockpit. The idea provoked outrage from some Ulster protestants and high anxiety for the British, concerned that the Pope might inadvertently enflame the situation or embarrass the British by raising difficult issues. But there were hopes too that an unequivocal condemnation of violence by the head of the Catholic Church, might help to bring the conflict to an end. This article, based on extensive research in diplomatic archives, reveals deep divisions within the Catholic Church on the Irish question and points to the power and limitations of the British diplomatic reach into the Vatican. It reveals also, however, the powerlessness of prayer and pleadings in the face of terrorist violence

    Constructing Entanglement Witness Via Real Skew-Symmetric Operators

    Full text link
    In this work, new types of EWs are introduced. They are constructed by using real skew-symmetric operators defined on a single party subsystem of a bipartite dxd system and a maximal entangled state in that system. A canonical form for these witnesses is proposed which is called canonical EW in corresponding to canonical real skew-symmetric operator. Also for each possible partition of the canonical real skew-symmetric operator corresponding EW is obtained. The method used for dxd case is extended to d1xd2 systems. It is shown that there exist Cd2xd1 distinct possibilities to construct EWs for a given d1xd2 Hilbert space. The optimality and nd-optimality problem is studied for each type of EWs. In each step, a large class of quantum PPT states is introduced. It is shown that among them there exist entangled PPT states which are detected by the constructed witnesses. Also the idea of canonical EWs is extended to obtain other EWs with greater PPT entanglement detection power.Comment: 40 page

    Efficient measurements, purification, and bounds on the mutual information

    Full text link
    When a measurement is made on a quantum system in which classical information is encoded, the measurement reduces the observers average Shannon entropy for the encoding ensemble. This reduction, being the {\em mutual information}, is always non-negative. For efficient measurements the state is also purified; that is, on average, the observers von Neumann entropy for the state of the system is also reduced by a non-negative amount. Here we point out that by re-writing a bound derived by Hall [Phys. Rev. A {\bf 55}, 100 (1997)], which is dual to the Holevo bound, one finds that for efficient measurements, the mutual information is bounded by the reduction in the von Neumann entropy. We also show that this result, which provides a physical interpretation for Hall's bound, may be derived directly from the Schumacher-Westmoreland-Wootters theorem [Phys. Rev. Lett. {\bf 76}, 3452 (1996)]. We discuss these bounds, and their relationship to another bound, valid for efficient measurements on pure state ensembles, which involves the subentropy.Comment: 4 pages, Revtex4. v3: rewritten and reinterpreted somewha

    Interface roughening with nonlinear surface tension

    Full text link
    Using stability arguments, this Brief Report suggests that a term that enhances the surface tension in the presence of large height fluctuations should be included in the Kardar-Parisi-Zhang equation. A one-loop renormalization group analysis then shows for interface dimensions larger than 3.3\simeq 3.3 an unstable strong-coupling fixed point that enters the system from infinity. The relevance of these results to the roughening transition is discussed.Comment: 4 pages RevTeX, 1 figur

    Topological order in 1D Cluster state protected by symmetry

    Full text link
    We demonstrate how to construct the Z2*Z2 global symmetry which protects the ground state degeneracy of cluster states for open boundary conditions. Such a degeneracy ultimately arises because the set of stabilizers do not span a complete set of integrals of motion of the cluster state Hamiltonian for open boundary conditions. By applying control phase transformations, our construction makes the stabilizers into the Pauli operators spanning the qubit Hilbert space from which the degeneracy comes.Comment: 1 figure, To be published in Quantum Information Processin

    Mutation in NSUN2, which Encodes an RNA Methyltransferase, Causes Autosomal-Recessive Intellectual Disability

    Get PDF
    Causes of autosomal-recessive intellectual disability (ID) have, until very recently, been under researched because of the high degree of genetic heterogeneity. However, now that genome-wide approaches can be applied to single multiplex consanguineous families, the identification of genes harboring disease-causing mutations by autozygosity mapping is expanding rapidly. Here, we have mapped a disease locus in a consanguineous Pakistani family affected by ID and distal myopathy. We genotyped family members on genome-wide SNP microarrays and used the data to determine a single 2.5 Mb homozygosity-by-descent (HBD) locus in region 5p15.32–p15.31; we identified the missense change c.2035G>A (p.Gly679Arg) at a conserved residue within NSUN2. This gene encodes a methyltransferase that catalyzes formation of 5-methylcytosine at C34 of tRNA-leu(CAA) and plays a role in spindle assembly during mitosis as well as chromosome segregation. In mouse brains, we show that NSUN2 localizes to the nucleolus of Purkinje cells in the cerebellum. The effects of the mutation were confirmed by the transfection of wild-type and mutant constructs into cells and subsequent immunohistochemistry. We show that mutation to arginine at this residue causes NSUN2 to fail to localize within the nucleolus. The ID combined with a unique profile of comorbid features presented here makes this an important genetic discovery, and the involvement of NSUN2 highlights the role of RNA methyltransferase in human neurocognitive development

    Quantum circuits for spin and flavor degrees of freedom of quarks forming nucleons

    Full text link
    We discuss the quantum-circuit realization of the state of a nucleon in the scope of simple symmetry groups. Explicit algorithms are presented for the preparation of the state of a neutron or a proton as resulting from the composition of their quark constituents. We estimate the computational resources required for such a simulation and design a photonic network for its implementation. Moreover, we highlight that current work on three-body interactions in lattices of interacting qubits, combined with the measurement-based paradigm for quantum information processing, may also be suitable for the implementation of these nucleonic spin states.Comment: 5 pages, 2 figures, RevTeX4; Accepted for publication in Quantum Information Processin

    High dimensional behavior of the Kardar-Parisi-Zhang growth dynamics

    Full text link
    We investigate analytically the large dimensional behavior of the Kardar-Parisi-Zhang (KPZ) dynamics of surface growth using a recently proposed non-perturbative renormalization for self-affine surface dynamics. Within this framework, we show that the roughness exponent α\alpha decays not faster than α1/d\alpha\sim 1/d for large dd. This implies the absence of a finite upper critical dimension.Comment: RevTeX, 4 pages, 2 figures. To appear in Phys. Rev.
    corecore