Time-optimal Unitary Operations in Ising Chains II: Unequal Couplings and Fixed Fidelity

We analytically determine the minimal time and the optimal control laws required for the realization, up to an assigned fidelity and with a fixed energy available, of entangling quantum gates ($\mathrm{CNOT}$) between indirectly coupled qubits of a trilinear Ising chain. The control is coherent and open loop, and it is represented by a local and continuous magnetic field acting on the intermediate qubit. The time cost of this local quantum operation is not restricted to be zero. When the matching with the target gate is perfect (fidelity equal to one) we provide exact solutions for the case of equal Ising coupling. For the more general case when some error is tolerated (fidelity smaller than one) we give perturbative solutions for unequal couplings. Comparison with previous numerical solutions for the minimal time to generate the same gates with the same Ising Hamiltonian but with instantaneous local controls shows that the latter are not time-optimal.Comment: 11 pages, no figure

Global analysis of electromagnetic moments in odd near doubly magic nuclei

We use the nuclear DFT approach to determine nuclear electric quadrupole and magnetic dipole moments in all one-particle and one-hole neighbors of eight doubly magic nuclei. We align angular momenta along the intrinsic axial-symmetry axis with broken time-reversal symmetry, which allows us to explore fully the self-consistent charge, spin, and current polarizations. Spectroscopic moments are determined for symmetry-restored wave functions and compared with available experimental data. We find that the obtained polarizations do not call for using quadrupole- or dipole-moment operators with effective charges or effective g-factors.Comment: 15 LaTeX pages, 9 figure

The Serret-Andoyer Riemannian metric and Euler-Poinsot rigid body motion

The Euler-Poinsot rigid body motion is a standard mechanical system and is the model for left-invariant Riemannian metrics on SO(3). In this article, using the Serret-Andoyer variables we parameterize the solutions and compute the Jacobi fields in relation with the conjugate locus evaluation. Moreover the metric can be restricted to a 2D surface and the conjugate points of this metric are evaluated using recent work [4] on surfaces of revolution

Monotonically convergent optimal control theory of quantum systems with spectral constraints on the control field

We propose a new monotonically convergent algorithm which can enforce spectral constraints on the control field (and extends to arbitrary filters). The procedure differs from standard algorithms in that at each iteration the control field is taken as a linear combination of the control field (computed by the standard algorithm) and the filtered field. The parameter of the linear combination is chosen to respect the monotonic behavior of the algorithm and to be as close to the filtered field as possible. We test the efficiency of this method on molecular alignment. Using band-pass filters, we show how to select particular rotational transitions to reach high alignment efficiency. We also consider spectral constraints corresponding to experimental conditions using pulse shaping techniques. We determine an optimal solution that could be implemented experimentally with this technique.Comment: 16 pages, 4 figures. To appear in Physical Review

Merchandising:Una técnica para vender más

El Merchandising, es el conjunto de técnicas aplicadas de forma conjunta o separada, por distribuidores y fabricantes, teniendo como objetivo el de aumentar la rentabilidad de sus puntos de venta, al mismo tiempo, por tanto, se da mayor salida a los productos, mediante una adaptación permanente del producto a las necesidades del mercado y la presentación correcta de la mercadería. El Merchandising beneficia a todos, pero debemos resaltar que permite maximizar el punto de venta ya que nuestros productos salen al encuentro directamente con el comprador; el comprador, sin necesidad de tener a alguien a su lado, se encuentra a gusto en el punto de venta, comprende el uso del producto, contesta por sí mismo sus interrogantes, disfruta el ambiente creado dentro de la tienda. En fin, el conjunto de sentidos por el cual el cliente se mueve alrededor de un ambiente apegado a las nuevas tendencias del Merchandising es el ideal para cualquier compra ya sea por necesidad o por impulso

Progresses in the development of a Step-NC compliant additive manufacturing system

The new standard of numerical control, known as STEP-NC, is categorized as the future of the advanced manufacturing systems. Greater flexibility and interoperability are some potential benefits offered by STEP-NC to meet the challenges of the new industrial landscape that is envisaged with the advent of Industry 4.0. Meanwhile, STEP-NC object-oriented programming has been partially applied and developed for machining processes (milling, turning...). But with the processes of additive manufacturing has not happened the same and the development is still incipient. This work presents the advances in the development of a new STEP-NC compliant additive manufacturing system, focusing particularly on the development of the information model. The application model activities in the IDEF0 nomenclature and application reference model in EXPRESS are presented. The AM-layer-feature concept has been introduced to define the manufacturing feature of additive processes based on material deposition layer-by-layer. Finally, a STEP-NC program generated from the EXPRESS model is presented, which can be implemented on an additive manufacturing system to validate the proposed model.El nuevo estándar de control numérico, conocido como STEP-NC, es categorizado como el futuro de los sistemas avanzados de manufactura. Mayor flexibilidad e interoperabilidad son algunos de los potenciales beneficios que ofrece STEP-NC para enfrentar los desafíos del nuevo panorama industrial que se vislumbra con el advenimiento de la Industria 4.0. Mientras tanto, la programación orientada a objeto de STEP-NC ha sido parcialmente aplicada y desarrollada hasta el momento para los procesos de mecanizado (fresado, torneado…). Pero con los procesos de manufactura aditiva no ha sucedido lo mismo y el desarrollo es aún incipiente. Este trabajo presenta los avances en el desarrollo de un nuevo sistema de manufactura aditiva basado en STEP-NC, enfocándose particularmente sobre el desarrollo del modelo de información. EL modelo de actividades de aplicación en la nomenclatura del IDEF0 y el modelo de referencia de aplicación en EXPRESS son presentados. El concepto AM-layer-feature ha sido introducido para definir la feature de manufactura de los procesos aditivos basados en deposición de material capa por capa. Finalmente, se presenta un programa en STEP-NC generado desde el modelo EXPRESS, el cual puede ser implementado sobre un sistema de manufactura aditiva para validar el modelo propuesto

Geometric Approach to Pontryagin's Maximum Principle

Since the second half of the 20th century, Pontryagin's Maximum Principle has been widely discussed and used as a method to solve optimal control problems in medicine, robotics, finance, engineering, astronomy. Here, we focus on the proof and on the understanding of this Principle, using as much geometric ideas and geometric tools as possible. This approach provides a better and clearer understanding of the Principle and, in particular, of the role of the abnormal extremals. These extremals are interesting because they do not depend on the cost function, but only on the control system. Moreover, they were discarded as solutions until the nineties, when examples of strict abnormal optimal curves were found. In order to give a detailed exposition of the proof, the paper is mostly self\textendash{}contained, which forces us to consider different areas in mathematics such as algebra, analysis, geometry.Comment: Final version. Minors changes have been made. 56 page

The Eukaryotic Promoter Database (EPD): recent developments

The Eukaryotic Promoter Database (EPD) is an annotated non-redundant collection of eukaryotic POL II promoters, for which the transcription start site has been determined experimentally. Access to promoter sequences is provided by pointers to positions in nucleotide sequence entries. The annotation part of an entry includes description of the initiation site mapping data, cross-references to other databases, and bibliographic references. EPD is structured in a way that facilitates dynamic extraction of biologically meaningful promoter subsets for comparative sequence analysis. Recent efforts have focused on exhaustive cross-referencing to the EMBL nucleotide sequence database, and on the improvement of the WWW-based user interfaces and data retrieval mechanisms. EPD can be accessed at http://www.epd.isb-sib.c

Protein Kinase B Regulates T Lymphocyte Survival, Nuclear Factor κb Activation, and Bcl-XL Levels in Vivo

The serine/threonine kinase protein kinase B (PKB)/Akt mediates cell survival in a variety of systems. We have generated transgenic mice expressing a constitutively active form of PKB (gag-PKB) to examine the effects of PKB activity on T lymphocyte survival. Thymocytes and mature T cells overexpressing gag-PKB displayed increased active PKB, enhanced viability in culture, and resistance to a variety of apoptotic stimuli. PKB activity prolonged the survival of CD4+CD8+ double positive (DP) thymocytes in fetal thymic organ culture, but was unable to prevent antigen-induced clonal deletion of thymocytes expressing the major histocompatibility complex class I–restricted P14 T cell receptor (TCR). In mature T lymphocytes, PKB can be activated in response to TCR stimulation, and peptide-antigen–specific proliferation is enhanced in T cells expressing the gag-PKB transgene. Both thymocytes and T cells overexpressing gag-PKB displayed elevated levels of the antiapoptotic molecule Bcl-XL. In addition, the activation of peripheral T cells led to enhanced nuclear factor (NF)-κB activation via accelerated degradation of the NF-κB inhibitory protein IκBα. Our data highlight a physiological role for PKB in promoting survival of DP thymocytes and mature T cells, and provide evidence for the direct association of three major survival molecules (PKB, Bcl-XL, and NF-κB) in vivo in T lymphocytes

A connection between optimal control theory and adiabatic passage techniques in quantum systems

This work explores the relationship between optimal control theory and adiabatic passage techniques in quantum systems. The study is based on a geometric analysis of the Hamiltonian dynamics constructed from the Pontryagin Maximum Principle. In a three-level quantum system, we show that the Stimulated Raman Adiabatic Passage technique can be associated to a peculiar Hamiltonian singularity. One deduces that the adiabatic pulse is solution of the optimal control problem only for a specific cost functional. This analysis is extended to the case of a four-level quantum system.Comment: 19 pages, 6 figure