A relational quantum computer using only two-qubit total spin measurement and an initial supply of highly mixed single qubit states

We prove that universal quantum computation is possible using only (i) the physically natural measurement on two qubits which distinguishes the singlet from the triplet subspace, and (ii) qubits prepared in almost any three different (potentially highly mixed) states. In some sense this measurement is a `more universal' dynamical element than a universal 2-qubit unitary gate, since the latter must be supplemented by measurement. Because of the rotational invariance of the measurement used, our scheme is robust to collective decoherence in a manner very different to previous proposals - in effect it is only ever sensitive to the relational properties of the qubits.Comment: TR apologises for yet again finding a coauthor with a ridiculous middle name [12

Métodos electroquímicos semicuantitativos de estudio de lo corrosión por picaduras del acero para armaduras de hormigón

El acero embebido en el hormigón se encuentra sometido a un medio de elevada alcalinidad (pH comprendido entre 12 y 13), debido a la cal libre, a los álcalis que contiene el cemento, y al Ca(0H)2 que se forma durante la hidratación de los silicatos. En esta situación, el acero se halla recubierto por una capa de óxidos e hidróxidos estables que lo mantienen pasivado, interponiendo una barrera entre él y los agentes agresivos

Determinación electroquímica cuantitativa de la velocidad de corrosión de un acero de construcción. Evaluación de la susceptibilidad al ataque por picaduras. Parte I: Ensayos en disolución saturada de hidróxido cálcico

En un trabajo anterior (1) se analizaron las distintas características de los métodos electroquímicos empleados hasta la actualidad para la detección del ataque localizado en el caso de un acero de construcción sumergido en disolución saturada de hidróxido cálcico, así como el efecto despasivante e inhibidor que sobre la corrosión del acero tienen los iones Cl- y NO2-, respectivamente, añadidos a dicho medio

Surface integrity of new dry-electropolishing technology on WC-Co cemented carbides

This study is focused on WC-Co dry-electropolished by DryLyte® technology that allows to obtain corrosion-free surfaces with a roughness below 9 nm. The main goal behind this research is to investigate the surface integrity trying to correlate the remanent microstructure after different dry-electropolishing times as a function of the hardness and elastic modulus evolution though massive nanoindentation. The quality of the surfacehas been evaluated by using advanced characterization techniques and the mechanical response treated by using the statistical methodology proposed by Ulm and Constantinides. To sum up, a close correlation is observed between the residual microstructure and the surface integrity in terms of hardness and elastic modulus maps.Peer ReviewedPostprint (published version

La tuberculose bovine à Madagascar

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The Measurement Calculus

Measurement-based quantum computation has emerged from the physics community as a new approach to quantum computation where the notion of measurement is the main driving force of computation. This is in contrast with the more traditional circuit model which is based on unitary operations. Among measurement-based quantum computation methods, the recently introduced one-way quantum computer stands out as fundamental. We develop a rigorous mathematical model underlying the one-way quantum computer and present a concrete syntax and operational semantics for programs, which we call patterns, and an algebra of these patterns derived from a denotational semantics. More importantly, we present a calculus for reasoning locally and compositionally about these patterns. We present a rewrite theory and prove a general standardization theorem which allows all patterns to be put in a semantically equivalent standard form. Standardization has far-reaching consequences: a new physical architecture based on performing all the entanglement in the beginning, parallelization by exposing the dependency structure of measurements and expressiveness theorems. Furthermore we formalize several other measurement-based models: Teleportation, Phase and Pauli models and present compositional embeddings of them into and from the one-way model. This allows us to transfer all the theory we develop for the one-way model to these models. This shows that the framework we have developed has a general impact on measurement-based computation and is not just particular to the one-way quantum computer.Comment: 46 pages, 2 figures, Replacement of quant-ph/0412135v1, the new version also include formalization of several other measurement-based models: Teleportation, Phase and Pauli models and present compositional embeddings of them into and from the one-way model. To appear in Journal of AC