Quantum Phase Transitions detected by a local probe using Time Correlations and Violations of Leggett-Garg Inequalities

In the present paper we introduce a way of identifying quantum phase transitions of many-body systems by means of local time correlations and Leggett-Garg inequalities. This procedure allows to experimentally determine the quantum critical points not only of finite-order transitions but also those of infinite order, as the Kosterlitz-Thouless transition that is not always easy to detect with current methods. By means of simple analytical arguments for a general spin-$1 / 2$ Hamiltonian, and matrix product simulations of one-dimensional $X X Z$ and anisotropic $X Y$ models, we argue that finite-order quantum phase transitions can be determined by singularities of the time correlations or their derivatives at criticality. The same features are exhibited by corresponding Leggett-Garg functions, which noticeably indicate violation of the Leggett-Garg inequalities for early times and all the Hamiltonian parameters considered. In addition, we find that the infinite-order transition of the $X X Z$ model at the isotropic point can be revealed by the maximal violation of the Leggett-Garg inequalities. We thus show that quantum phase transitions can be identified by purely local measurements, and that many-body systems constitute important candidates to observe experimentally the violation of Leggett-Garg inequalities.Comment: Minor changes, 11 pages, 11 figures. Final version published in Phys. Rev.

Dynamics of Entanglement and the Schmidt Gap in a Driven Light-Matter System

The ability to modify light-matter coupling in time (e.g. using external pulses) opens up the exciting possibility of generating and probing new aspects of quantum correlations in many-body light-matter systems. Here we study the impact of such a pulsed coupling on the light-matter entanglement in the Dicke model as well as the respective subsystem quantum dynamics. Our dynamical many-body analysis exploits the natural partition between the radiation and matter degrees of freedom, allowing us to explore time-dependent intra-subsystem quantum correlations by means of squeezing parameters, and the inter-subsystem Schmidt gap for different pulse duration (i.e. ramping velocity) regimes -- from the near adiabatic to the sudden quench limits. Our results reveal that both types of quantities indicate the emergence of the superradiant phase when crossing the quantum critical point. In addition, at the end of the pulse light and matter remain entangled even though they become uncoupled, which could be exploited to generate entangled states in non-interacting systems.Comment: 15 pages, 4 figures, Accepted for publication in Journal of Physics B, special issue Correlations in light-matter interaction

Influence of the molecular interaction in the value of molecular volume for the isotropicnematic transition of p-azoxianisol using th emodel HERSW in conjuntion with IPCM model

In this work, we analyzed the experimental pressure-temperature behavior in the Isotropic-Nematic phase transitionfor the liquid crystal p-azoxianisol at 1 atm using a development for the HERSW Conveg Peg model. Additionally, we obtained the values of the molecular volumes for the hard and attractive cores from theoretical quantum calculations at PM3, PM6 and B3LYP/6-311++G levels considering the molecular interaction among the liquidcrystals (PAA)5. We found that the best prediction for experimental data appears when the effect of the molecular interaction is considered in the volume calculation. Specifically for a/b=3.7, V0=70.86 A3 and a/bl=1.95 the best prediction was obtained

Uprolides N, O and P from the Panamanian Octocoral Eunicea succinea.

Three new diterpenes, uprolide N (1), uprolide O (2), uprolide P (3) and a known one, dolabellane (4), were isolated from the CH₂Cl₂-MeOH extract of the gorgonian octocoral Eunicea succinea, collected from Bocas del Toro, on the Caribbean coast of Panama. Their structures were determined using spectroscopic analyses, including 1D and 2D NMR and high-resolution mass spectrometry (HRMS) together with molecular modeling studies. Compounds 1-3 displayed anti-inflammatory properties by inhibiting production of Tumor Necrosis Factor (TNF) and Interleukin (IL)-6 induced by lipopolysaccharide (LPS) in murine macrophages

Enhancing violations of Leggett-Garg inequalities in nonequilibrium correlated many-body systems by interactions and decoherence

We identify different schemes to enhance the violation of Leggett-Garg inequalities in open many-body systems. Considering a nonequilibrium archetypical setup of quantum transport, we show that particle interactions control the direction and amplitude of maximal violation and that in the strongly-interacting and strongly-driven regime bulk dephasing enhances the violation. Through an analytical study of a minimal model, we unravel the basic ingredients to explain this decoherence-enhanced quantumness, illustrating that such an effect emerges in a wide variety of systems.Comment: Main text: 9 pages, 6 Figures, Supplemental Material: 7 pages, 4 Figures. Comments welcome to [email protected]

Sistema integrado de gestión de calidad, ambiente y seguridad para las empresas comercializadoras en el sector agropecuario en el municipio de Pivijay

The present article proposed an integrated system of quality management, environment and security for the commercializing companies of the agricultural sector in the municipality of Pivijay Magdalena, a methodology of qualitative type was used based primarily on the Colombian Technical Norms ISO 9001:2015, ISO-14001 2015, ISO 45001:2018, they were described meticulously and adapted to the agricultural sector, a proposal was made that will serve as guide to give answer to the question problem of the investigation, nevertheless, it can be adapted to another sector if it is required. The results obtained from the research are that the MiPymes were able to have scope to the standards and have a guide to the implementation of these.  The article concluded with a step by step of what was done during the whole study of the problem question, stating that an Integrated Management System can be built to these companies of the chosen sector through the suggested guidelinesEl presente artículo propuso un sistema integrado de gestión de calidad, ambiente y seguridad para las empresas comercializadoras del sector agropecuario en el municipio de Pivijay Magdalena, se utilizó una metodología de tipo cualitativa basándose primordialmente es las Normas Técnicas Colombiana ISO 9001:2015, ISO-14001 2015, ISO 45001:2018, se describieron minuciosamente y se adaptaron al sector agropecuario, se realizó una propuesta que servirá de guía para dar respuesta a la pregunta problema de la investigación, sin embargo, puede ser adaptado a otro sector si así se requiere. Los resultados obtenidos de la investigación es que las MiPymes pudieron tener alcance a las normas y tener una guía de la implementación de estas.  El articulo concluyó con un paso a paso de lo realizado durante todo el estudio de la pregunta problema, planteando que se puede construir un Sistema Integrado de Gestión a estas empresas del sector escogido mediante los lineamientos sugeridos

R\'enyi Entropy Singularities as Signatures of Topological Criticality in Coupled Photon-Fermion Systems

We show that the topological phase transition for a Kitaev chain embedded in a cavity can be identified by measuring experimentally accessible photon observables such as the Fano factor and the cavity quadrature amplitudes. Moreover, based on density matrix renormalization group numerical calculations, endorsed by an analytical Gaussian approximation for the cavity state, we propose a direct link between those observables and quantum entropy singularities. We study two bipartite entanglement measures, the von Neumann and R\'enyi entanglement entropies, between light and matter subsystems. Even though both display singularities at the topological phase transition points, remarkably only the R\'enyi entropy can be analytically connected to the measurable Fano factor. Consequently, we show a method to recover the bipartite entanglement of the system from a cavity observable. Thus, we put forward a path to experimentally access the control and detection of a topological quantum phase transition via the R\'enyi entropy, which can be measured by standard low noise linear amplification techniques in superconducting circuits. In this way, the main quantum information features of Majorana polaritons in photon-fermion systems can be addressed in feasible experimental setups.Comment: Main text: 13 pages, 9 figures. Published in Phys. Rev. Research as an Editors' Suggestio

The deep inferior epigastric artery perforator flap: a review

Breast cancer is recognized worldwide as a major health problem among women due to its high incidence and high mortality and morbidity rates. Breast reconstruction is an approach of great value for those patients who underwent mastectomy, impacting their quality of life and psychological stress. The deep inferior epigastric artery perforator (DIEP) flap was described as the preferred graft for breast reconstruction with an autologous flap by surgeons because it represented a decrease in complications for the time and obtained better results. DIEP flap reconstruction requires microsurgical skills as well as continuous monitoring of the patient to identify and resolve possible associated complications.

Analysis and implementation of different topologies of transversal filters in planar technology

This paper uses a simple configuration to implement microwave transversal filters based on microstrip technology. The structure is of second order and implements two transmission zeros and two reflection zeros in the frequency response of the filter. The basic configuration consists of input and output ports coupled in a shunt configuration to two printed resonators of different lengths. A modification of the original structure is introduced to allow an additional direct coupling between the source and the load. Depending on the value and the sign of the coupling terms, different frequency responses can be obtained. In this way, small modifications in the basic structure allow to obtain band-pass or band-stop responses. Following this circuit topology, the paper discusses the possibilities to have transmission zeros in the real or in the complex plane and their effects on the frequency response and on the group delay of the filter. Also, two practical implementations in microstrip technology are proposed, and a third filter implementing group delay equalization is demonstrated. Measured results confirm theoretical predictions and validate the structures for practical applications.Ministerio de Educación y Ciencia, Ref. TEC2007-67630-C03-02. Fundación Séneca, Ref. 08833/PI/0