The time as an emergent property of quantum mechanics, a synthetic description of a first experimental approach

The "problem of time" in present physics substantially consists in the fact that a straightforward quantization of the general relativistic evolution equation and constraints generates for the Universe wave function the Wheeler-De Witt equation, which describes a static Universe. Page and Wootters considered the fact that there exist states of a system composed by entangled subsystems that are stationary, but one can interpret the component subsystems as evolving: this leads them to suppose that the global state of the universe can be envisaged as one of this static entangled state, whereas the state of the subsystems can evolve. Here we synthetically present an experiment, based on PDC polarization entangled photons, that allows showing with a practical example a situation where this idea works, i.e. a subsystem of an entangled state works as a "clock" of another subsystem

Statistical Estimation of Quantum Tomography Protocols Quality

A novel operational method for estimating the efficiency of quantum state tomography protocols is suggested. It is based on a-priori estimation of the quality of an arbitrary protocol by means of universal asymptotic fidelity distribution and condition number, which takes minimal value for better protocol. We prove the adequacy of the method both with numerical modeling and through the experimental realization of several practically important protocols of quantum state tomography

Матричный Анализ Препятствий Инновационной Деятельности Для Управления Многоотраслевым Комплексом

This paper examines obstacles to innovation in a multisectoral complex. The purpose of this study is to assess the criticality of these obstacles given the sectoral heterogeneity in order to differentiate innovative policies. The research is based on the methods of matrix analysis and mathematical processing of statistical data. Numerous publications on the use of matrix models in strategic planning and management of economic development served as the information and theoretical basis for this study. To achieve the goal of the study, the authors introduce the concept of the matrix of sectoral heterogeneity of obstacles to innovation. The approach to the formation and use of this matrix is shown by the example of the diversified agro-industrial complex (AIC). The results of the study may be of practical interest in determining the priority management measures of innovation policyEste documento examina los obstáculos a la innovación en un complejo multisectorial. El propósito de este estudio es evaluar la importancia de estos obstáculos dada la heterogeneidad sectorial para diferenciar políticas innovadoras. La investigación se basa en los métodos de análisis matricial y procesamiento matemático de datos estadísticos. Numerosas publicaciones sobre el uso de modelos matriciales en la planificación estratégica y la gestión del desarrollo económico sirvieron de base teórica y de información para este estudio. Para lograr el objetivo del estudio, los autores introducen el concepto de matriz de heterogeneidad sectorial de obstáculos a la innovación. El enfoque de la formación y el uso de esta matriz se muestra en el ejemplo del complejo agroindustrial diversificado (AIC). Los resultados del estudio pueden ser de interés práctico para determinar las medidas de gestión prioritarias de la política de innovaciónПредмет исследования – препятствия инновационной деятельности в многоотраслевом комплексе. Цель исследования – оценка критичности этих препятствий с учетом отраслевой неоднородности для дифференциации мер инновационной политики. Исследование опирается на методы матричного анализа и математической обработки статистических данных. Информационно-теоретическая база исследования – публикации по использованию матричных моделей в задачах стратегического планирования и управления экономическим развитием. Для достижения цели исследования вводится понятие матрицы отраслевой неоднородности препятствий инновационной деятельности. Подход к формированию и использованию данной матрицы демонстрируется на таком многоотраслевом комплексе как АПК. Результаты исследования могут представлять практический интерес с позиции определения приоритетных управленческих воздействий инновационной политики

Polarization ququarts

We discuss the concept of polarization states of four-dimensional quantum systems based on frequency non-degenerate biphoton field. Several quantum tomography protocols were developed and implemented for measurement of an arbitrary state of ququart. A simple method that does not rely on interferometric technique is used to generate and measure the sequence of states that can be used for quantum communication purposes.Comment: 13 pages, 10 figure

On Preparing Entangled Pairs of Polarization Qubits in the Frequency Non-Degenerate Regime

The problems associated with practical implementation of the scheme proposed for preparation of arbitrary states of polarization ququarts based on biphotons are discussed. The influence of frequency dispersion effects are considered, and the necessity of group velocities dispersion compensation in the frequency non-degenerate case even for continuous pumping is demonstrated. A method for this compensation is proposed and implemented experimentally. Physical restrictions on the quality of prepared two-photon states are revealed.Comment: 9 pages, 6 figure

Nanodiamond quantum sensors reveal temperature variation associated to hippocampal neurons firing

Temperature is one of the most relevant parameters for the regulation of intracellular processes. Measuring localized subcellular temperature gradients is fundamental for a deeper understanding of cell function, such as the genesis of action potentials, and cell metabolism. Here, we detect for the first time temperature variations (1{\deg}C) associated with potentiation and depletion of neuronal firing, exploiting a nanoscale thermometer based on optically detected magnetic resonance in nanodiamonds. Our results provide a tool for assessing neuronal spiking activity under physiological and pathological conditions and, conjugated with the high sensitivity of this technique (in perspective sensitive to < 0.1{\deg}C variations), pave the way to a systematic study of the generation of localized temperature gradients. Furthermore, they prompt further studies explaining in detail the physiological mechanism originating this effect.Comment: 27 pages, 5 figures, 3 table