Cosmological aspects of the unimodular-mimetic f(G)f(\mathcal{G}) gravity

In this work we introduce and study the unimodular-mimetic $f(\mathcal{G})$ gravity, where unimodular and mimetic constraints are incorporated through corresponding Lagrange multipliers. We present field equations governing this theory and discuss their main properties. By using the reconstruction scheme, we obtain quadratic unimodular-mimetic $f(\mathcal{G})=A\mathcal{G}^2$ gravity capable of describing hybrid expansion law and the power law evolution. Furthermore, we employ an inverted reconstruction technique in order to derive specific $f(\mathcal{G})$ function that reproduces the Hubble rate of symmetric bounce. The unimodular-mimetic $f(\mathcal{G})=A\mathcal{G}^2$ is also shown to be compatible with the BICEP2/Keck and Planck data. To this end, we incorporate updated constraints on the scalar-to-tensor ratio and spectral index, utilizing a perfect fluid approach to the slow-roll parameters. Through an analysis of that kind, we demonstrate that the theoretical framework presented here can indeed characterize inflation that agrees with the observational findings. Consequently, the introduced extension appears to have potential to describe and encompass a wide spectrum of cosmological models.Comment: 16 pages, 2 figures, appendi

Measurement-induced nonlocality for observers near a black hole

We present a systematic and complementary study of quantum correlations near a black hole by considering the measurement-induced nonlocality (MIN). The quantum measure of interest is discussed on the same footing for the fermionic, bosonic and mixed fermion-boson modes in relation to the Hawking radiation. The obtained results show that in the infinite Hawking temperature limit, the physically accessible correlations does not vanish only in the fermionic case. However, the higher frequency modes can sustain correlations for the finite Hawking temperature, with mixed system being more sensitive towards increase of the fermionic frequencies than the bosonic ones. Since the MIN for the latter modes quickly diminishes, the increased frequency may be a way to maintain nonlocal correlations for the scenarios at the finite Hawking temperature.Comment: 4 figure

Effective potential for Polyakov loops from a center symmetric effective theory in three dimensions

We present lattice simulations of a center symmetric dimensionally reduced effective field theory for SU(2) Yang Mills which employ thermal Wilson lines and three-dimensional magnetic fields as fundamental degrees of freedom. The action is composed of a gauge invariant kinetic term, spatial gauge fields and a potential for the Wilson line which includes a "fuzzy" bag term to generate non-perturbative fluctuations. The effective potential for the Polyakov loop is extracted from the simulations including all modes of the loop as well as for cooled configuration where the hard modes have been averaged out. The former is found to exhibit a non-analytic contribution while the latter can be described by a mean-field like ansatz with quadratic and quartic terms, plus a Vandermonde potential which depends upon the location within the phase diagram.Comment: 10 pages, 22 figures, v2: published version (minor clarifications, update of reference list

Service interdependencies: insight into use cases for service composition

The paper analyses several most appealing use cases for Semantic Web services and their composition. They are considered from the perspective of service types, QoS parameters, semantic description and user preferences. We introduce different levels of service composition and discuss implications of the above.Applications in Artificial Intelligence - Ontologies and Intelligent WebRed de Universidades con Carreras en Informática (RedUNCI

Entropy of financial time series due to the shock of war

The concept of entropy is not uniquely relevant to the statistical mechanics but among others it can play pivotal role in the analysis of a time series, particularly the stock market data. In this area sudden events are especially interesting as they describe abrupt data changes which may have long-lasting effects. Here, we investigate the impact of such events on the entropy of financial time series. As a case study we assume data of polish stock market in the context of its main cumulative index. This index is discussed for the finite time periods before and after outbreak of the 2022 Russian invasion of Ukraine, acting as the sudden event. The analysis allows us to validate the entropy-based methodology in assessing market changes as driven by the extreme external factors. We show that qualitative features of market changes can be captured quantitatively in terms of the entropy. In addition to that, the magnitude of the impact is analysed over various time periods in terms of the introduced entropic index. To this end, the present work also attempts to answer whether or not the recent war can be considered as a reason or at least catalyst to the current economic crisis.Comment: 8 pages, 5 figure

Economization methods used by low-cost airlines : an overview

PURPOSE: The crisis caused by the pandemic has forced airlines (both full-service carriers (FCC) and low cost carriers (LCC)) to review their business models and look for opportunities to make up for losses. The goal of this paper is to review the cost optimization methods used by LCC airlines and to identify the activities of LCC that were taken to reduce costs.DESIGN/METHODOLOGY/APPROACH: The analysis of the areas of economization of activities undertaken by the LCC carried out in the article is the result of a literature review of business models used by LCC carriers.FINDINGS: The conducted literature analysis allowed for the identification of seven main areas in which measures are taken to reduce the costs of the LCC line.PRACTICAL IMPLICATIONS: Economization methods implemented by LCC lines at the strategic level reduce the carrier's costs and can be adapted to the market in which it operates.ORIGINALITY/VALUE: Although the business models used by LCC lines are not a new topic, the review of economization methods from a strategic perspective presented in the article has not been discussed in the literature.peer-reviewe

Service interdependencies: insight into use cases for service composition

The paper analyses several most appealing use cases for Semantic Web services and their composition. They are considered from the perspective of service types, QoS parameters, semantic description and user preferences. We introduce different levels of service composition and discuss implications of the above.Applications in Artificial Intelligence - Ontologies and Intelligent WebRed de Universidades con Carreras en Informática (RedUNCI

Service interdependencies: insight into use cases for service composition

Abstract. The paper analyses several most appealing use cases for Semantic Web services and their composition. They are considered from the perspective of service types, QoS parameters, semantic description and user preferences. We introduce different levels of service composition and discuss implications of the above