The CWKB particle production and classical condensate in de Sitter spacetime

The complex time WKB approximation is an effective tool in studying particle production in curved spacetime. We use it in this work to understand the formation of classical condensate in expanding de Sitter spacetime. The CWKB leads to the emergence of thermal spectrum that depends crucially on horizons (as in de Sitter spacetime) or observer dependent horizons (as in Rindler spacetime). A connection is sought between the horizon and the formation of classical condensate. We concentrate on de Sitter spacetime and study the cosmological perturbation of $k=0$ mode with various values of $m/H_0$. We find that for a minimally coupled free scalar field for $m^2/H_0^2<2$, the one-mode occupation number grows more than unity soon after the physical wavelength of the mode crosses the Hubble radius and soon after diverges as $N(t)\sim O(1)[\lambda_{phys}(t)/{H_0^{-1}}]^{2\sqrt{\nu^2-1/4}}$, where $\nu\equiv (9/4 -m^2/{H_0^2})^{1/2}$. The results substantiates the previous works in this direction. We also find the correct oscillation and behaviour of $N(z)$ at small $z$ from a single expression using CWKB approximation for various values of $m/H_0$. We also discuss decoherence in relation to the formation of classical condensate. We also find that the squeezed state formalism and CWKB method give identical results.Comment: 19 pages, revtex, 5 figure

Liquid Lunch – Vampire Bats Feed On Invasive Feral Pigs And Other Ungulates

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Zonal flows and long-distance correlations during the formation of the edge shear layer in the TJ-II stellarator

A theoretical interpretation is given for the observed long-distance correlations in potential fluctuations in TJ-II. The value of the correlation increases above the critical point of the transition for the emergence of the plasma edge shear flow layer. Mean (i.e. surface averaged, zero-frequency) sheared flows cannot account for the experimental results. A model consisting of four envelope equations for the fluctuation level, the mean flow shear, the zonal flow amplitude shear, and the averaged pressure gradient is proposed. It is shown that the presence of zonal flows is essential to reproduce the main features of the experimental observations.Comment: 19 pages, 7 figure

The relationship between (social) IoT & Big Data

Os dispositivos Internet of Things (IoT) são primordialmente utilizados para conectar objetos físicos, enquanto as tecnologias sociais são responsáveis pela colaboração e interação social. A importância da Big Data não reside apenas na quantidade de dados que se possui, mas sim do que podemos fazer com eles. A criação do conceito de IoT permite estender a conectividade dos aparelhos digitais aos aparelhos físicos, que não estão ligados à Internet, e que usamos diariamente. Apesar da proximidade que estas duas áreas possuem, existem também características que as separam. Os objetivos do presente artigo concentram-se em apresentar Big Data e IoT, centrando depois atenções numa mais recente variação da IoT: Social IoT.info:eu-repo/semantics/publishedVersio

State of the art of artificial intelligence in internal audit context

Artificial intelligence (AI) is a technological field that stands out for what can do and for the advantages that can provide to various sectors of activity. An internal audit could benefit from the introduction of AI in its tasks, namely though the automation of audit processes that make it faster and more efficient allowing an increase in the degree of complexity of the tasks that internal auditors may perform. This will enhance the skills of internal auditors in fields like the determination of business processes and associated risks and controls in anticipated detection of fraud and the following up of anomalies in real-time. This article features a set of technologies of AI and the set of benefits it adds to the internal audit. Two models of internal audit applied to artificial intelligence demonstrate how internal audit and internal auditors must adapt to the new reality of AI, by not losing their purpose and by bringing benefits to organizations.info:eu-repo/semantics/acceptedVersio

Squeezed States of the Generalized Minimum Uncertainty State for the Caldirola-Kanai Hamiltonian

We show that the ground state of the well-known pseudo-stationary states for the Caldirola-Kanai Hamiltonian is a generalized minimum uncertainty state, which has the minimum allowed uncertainty $\Delta q \Delta p = \hbar \sigma_0/2$, where $\sigma_0 (\geq 1)$ is a constant depending on the damping factor and natural frequency. The most general symmetric Gaussian states are obtained as the one-parameter squeezed states of the pseudo-stationary ground state. It is further shown that the coherent states of the pseudo-stationary ground state constitute another class of the generalized minimum uncertainty states.Comment: RevTex4, 9 pages, no fingure; to be published in Journal of Physics

O paradigma da privacidade: um panorama geral sobre privacidade em Business Analytics e Big Data

In this New Age where information has an indispensable value for companies and data mining technologies are growing in the area of Information Technology, privacy remains a sensitive issue in the approach to the exploitation of the large volume of data generated and processed by companies. The way data is collected, handled and destined is not yet clearly defined and has been the subject of constant debate by several areas of activity. This literature review gives an overview of privacy in the era of Business Analytics and Big Data in different timelines, the opportunities and challenges faced, aiming to broaden discussions on a subject that deserves extreme attention and aims to show that, despite measures for data protection have been created, there is still a need to discuss the subject among the different parties involved in the process to achieve a positive ideal for both users and companies.info:eu-repo/semantics/acceptedVersio