Invertible condition of quantum Fisher information matrix for a mixed qubit

Estimating multiparamter simultaneously as precise as possible is an important goal of quantum metrolo- gy. As a first step to this end, here we give a condition determining whether two arbitrary parameters can be estimated simultaneously for a qubit in the mixed state. An application of this condition is shown.Comment: The European Physical Journal D 201

Diseño e implementación de una Red Lan para la Empresa Palinda

The management of the LAN and WAN networks has allowed companies and institutions to optimize the use of resources through a centralized network, allowing the availability of information in a secure and fast way. The present project seeks to integrate communication services, allowing the transmission of data from a central point to the different departments of PALINDA. The fact of performing an analysis of the requirements of the infrastructure allows us to determine a solution with the available technical resources and financially with low costs. PALINDA currently does not have any infrastructure communication technology, so to be able to manage the network in a single system, allows to streamline the procedures and processes so that users get updated information, systematized and in real time streamlining functions.La administración de las redes LAN y WAN en la actualidad ha permitido a las empresas e instituciones optimizar el uso de los recursos mediante una red centralizada permitiendo disponer la información de forma segura y rápida. El presente proyecto busca integrar servicios de comunicación, permitiendo la transmisión de datos desde un punto central hacia los diferentes departamentos de PALINDA. El hecho de realizar un análisis de los requerimientos de la infraestructura nos permite determinar una solución con los recursos técnicos disponibles y financieramente con costos bajos. PALINDA actualmente no cuenta con ninguna infraestructura tecnológica de comunicación por lo que poder administrar la red en un solo sistema, permitirá agilizar los trámites y procesos para que los usuarios obtengan la información actualizada, sistematizada y en tiempo real agilitando las funciones

Chern class inequalities on polarized manifolds and nef vector bundles

This article is concerned with Chern class and Chern number inequalities on polarized manifolds and nef vector bundles. For a polarized pair $(M,L)$ with $L$ very ample, our first main result is a family of sharp Chern class inequalities. Among them the first one is a variant of a classical result and the equality case of the second one is a characterization of hypersurfaces. The second main result is a Chern number inequality on it, which includes a reverse Miyaoka-Yau type inequality. The third main result is that the Chern numbers of a nef vector bundle over a compact K\"{a}hler manifold are bounded below by the Euler number. As an application, we classify compact K\"{a}hler manifolds with nonnegative bisectional curvature whose Chern numbers are all positive. A conjecture related to the Euler number of compact K\"{a}hler manifolds with nonpositive bisectional curvature is proposed, which can be regarded as a complex analogue to the Hopf conjecture.Comment: 19 pages, comments very welcome