Chiral symmetry restoration in (2+1)-dimensional QEDQED with a Maxwell-Chern-Simons term at finite temperature

We study the role played by a Chern-Simons contribution to the action in the $QED_3$ formulation of a two-dimensional Heisenberg model of quantum spin systems with a strictly fixed site occupation at finite temperature. We show how this contribution affects the screening of the potential which acts between spinons and contributes to the restoration of chiral symmetry in the spinon sector. The constant which characterizes the Chern-Simons term can be related to the critical temperature $T_c$ above which the dynamical mass goes to zero.Comment: 8 pages, 4 figure

Numerical study on Schramm-Loewner Evolution in nonminimal conformal field theories

The Schramm-Loewner evolution (SLE) is a powerful tool to describe fractal interfaces in 2D critical statistical systems. Yet the application of SLE is well established for statistical systems described by quantum field theories satisfying only conformal invariance, the so called minimal conformal field theories (CFTs). We consider interfaces in Z(N) spin models at their self-dual critical point for N=4 and N=5. These lattice models are described in the continuum limit by non-minimal CFTs where the role of a Z_N symmetry, in addition to the conformal one, should be taken into account. We provide numerical results on the fractal dimension of the interfaces which are SLE candidates for non-minimal CFTs. Our results are in excellent agreement with some recent theoretical predictions.Comment: 4 pages, 2 figures, v2: typos corrected, published versio

Site occupation constraints in mean-field approaches of quantum spin systems at finite temperature

We study the effect of site occupation on the description of quantum spin systems at finite temperature and mean-field level. We impose each lattice site to be occupied by a single electron. This is realized by means of a specific prescription. The outcome of the prescription is compared to the result obtained by means of a projection procedure which fixes the site occupation to one particle per site on an average. The comparison is performed for different representations of the Hamiltonian in Fock space leading to different types of mean-field solutions. The behaviour of order parameters is analyzed for each choice of the mean-field and constraint which fixes the occupation rate at each site. Sizable quantitative differences between the outcomes obtained with the two different constraints are observed.Comment: 18 pages, 2 figure

Chiral magnetic effect in the PNJL model

We study the two-flavor Nambu--Jona-Lasinio model with the Polyakov loop (PNJL model) in the presence of a strong magnetic field and a chiral chemical potential $\mu_5$ which mimics the effect of imbalanced chirality due to QCD instanton and/or sphaleron transitions. Firstly we focus on the properties of chiral symmetry breaking and deconfinement crossover under the strong magnetic field. Then we discuss the role of $\mu_5$ on the phase structure. Finally the chirality charge, electric current, and their susceptibility, which are relevant to the Chiral Magnetic Effect, are computed in the model.Comment: Some reference added. Minor revisions. One figure added. To appear on Phys. Rev.

Chiral magnetic effect in the PNJL model

We study the two-flavor Nambu--Jona-Lasinio model with the Polyakov loop (PNJL model) in the presence of a strong magnetic field and a chiral chemical potential $\mu_5$ which mimics the effect of imbalanced chirality due to QCD instanton and/or sphaleron transitions. Firstly we focus on the properties of chiral symmetry breaking and deconfinement crossover under the strong magnetic field. Then we discuss the role of $\mu_5$ on the phase structure. Finally the chirality charge, electric current, and their susceptibility, which are relevant to the Chiral Magnetic Effect, are computed in the model.Comment: Some reference added. Minor revisions. One figure added. To appear on Phys. Rev.

social media s impact on the consumer mindset when to use which sentiment extraction tool

Abstract User-generated content provides many opportunities for managers and researchers, but insights are hindered by a lack of consensus on how to extract brand-relevant valence and volume. Marketing studies use different sentiment extraction tools (SETs) based on social media volume, top-down language dictionaries and bottom-up machine learning approaches. This paper compares the explanatory and forecasting power of these methods over several years for daily customer mindset metrics obtained from survey data. For 48 brands in diverse industries, vector autoregressive models show that volume metrics explain the most for brand awareness and purchase intent, while bottom-up SETs excel at explaining brand impression, satisfaction and recommendation. Systematic differences yield contingent advice: the most nuanced version of bottom-up SETs (SVM with Neutral) performs best for the search goods for all consumer mind-set metrics but Purchase Intent for which Volume metrics work best. For experienced goods, Volume outperforms SVM with neutral. As processing time and costs increase when moving from volume to top-down to bottom-up sentiment extraction tools, these conditional findings can help managers decide when more detailed analytics are worth the investment

Place and power in tourism development: tracing the complex articulations of community and locality

This paper outlines the case for the analysis of tourism, power and place in the development process from a critical sociological perspective. It draws on recent trends in the sociology of development to develop existing theoretical models in a manner which transcends the more rigid dualisms between structure and agency on the one hand, and, the concerns of power and identity on the other. As in recent works from noted scholars such as Picard and Wood (1997), the relationship between tourism and processes of development and social transformation are more nuanced and varied than previous ‘theoretical’ models in tourism have recognised. Hence, this paper examines the issue by considering four major thematic areas of relevance to the study of tourism and its diverse relationships to processes of social change: the relations of community, consumption, production and place.Este artículo esboza el caso del análisis del turismo, el poder y el espacio en los procesos de desarrollo desde la perspectiva de la sociología crítica. Se sirve de las recientes tendencias en la sociología del desarrollo por extender los modelos teóricos existentes de manera que trascienda el rígido dualismo entre estructura y organismo de un lado, y acerca del poder y la identidad, por otro. Tal como han admitido en recientes trabajos destacados investigadores como Picard y Wood (1997), la relación entre turismo y procesos de desarrollo y transformación social están más matizados y variados que los modelos ‘teóricos’ previos. Desde este punto de vista, este artículo examina el tema considerando cuatro áreas temáticas de especial relevancia para el estudio del turismo y sus diversas relaciones con los procesos de cambio social: la relaciones de comunidad, consumo, producción y espacio

Cosmological tachyon condensation

We consider the prospects for dark matter/energy unification in k-essence type theories. General mappings are established between the k-essence scalar field, the hydrodynamic and braneworld descriptions. We develop an extension of the general relativistic dust model that incorporates the effects of both pressure and the associated acoustic horizon. Applying this to a tachyon model, we show that this inhomogeneous "variable Chaplygin gas" does evolve into a mixed system containing cold dark matter like gravitational condensate in significant quantities. Our methods can be applied to any dark energy model as well as to mixtures of dark energy and traditional dark matter.Comment: 22 pages, 3 figures, title changed, typos corrected, accepted in Phys. Rev.

Contested discourses in social tourism:A relational political economy perspective

Social tourism initiatives often have economic as well as objectives, particularly national schemes such as the Spanish IMSERSO programme, designed to stimulate off-season tourism in mass coastal tourism destinations. Yet, there is little evidence of how such schemes responded to crises or that explores the effects on the tourism industry actors responsible for programme delivery. This article applies a relational political economy approach to assess the contested discourses surrounding the governance of the scheme. We examine the evolution of the IMSERSO programme longitudinally following the global financial crisis and up until the COVID-19 pandemic to assess the relational dynamics at play social tourism governance on destination stakeholders, outlining implications for social tourism policies internationally