First order flow equations for nonextremal black holes in AdS (super)gravity

We consider electrically charged static nonextremal black holes in $d$-dimensional Einstein-Maxwell-(A)dS gravity, whose horizon is a generic Einstein space in $d-2$ dimensions. It is shown that for this system the Hamilton-Jacobi equation is exactly solvable and admits two branches of solutions. One of them exhibits a non-simply connected domain of integration constants and does not reduce to the well-known solution for the $d=4$ BPS case. The principal functions generate two first order flows that are analytically different, but support the same general solution. One of the two sets of flow equations corresponds to those found by L\"u, Pope and V\'azquez-Poritz in hep-th/0307001 and (for $d=4$ and $\Lambda=0$) by Miller, Schalm and Weinberg in hep-th/0612308. This clarifies also the reason for the very existence of first order equations for nonextremal black holes, namely, they are just the expressions for the conjugate momenta in terms of derivatives of the principal function in a Hamilton-Jacobi formalism. In the last part of our paper we analyze how much of these integrability properties generalizes to matter-coupled $N=2$, $d=4$ gauged supergravity.Comment: 17 pages. v2: Refs. added. v3: Final version to appear in JHE

On the integrability of Einstein-Maxwell-(A)dS gravity in presence of Killing vectors

We study some symmetry and integrability properties of four-dimensional Einstein-Maxwell gravity with nonvanishing cosmological constant in the presence of Killing vectors. First of all, we consider stationary spacetimes, which lead, after a timelike Kaluza-Klein reduction followed by a dualization of the two vector fields, to a three-dimensional nonlinear sigma model coupled to gravity, whose target space is a noncompact version of $\mathbb{C}\text{P}^2$ with SU(2,1) isometry group. It is shown that the potential for the scalars, that arises from the cosmological constant in four dimensions, breaks three of the eight SU(2,1) symmetries, corresponding to the generalized Ehlers and the two Harrison transformations. This leaves a semidirect product of a one-dimensional Heisenberg group and a translation group $\mathbb{R}^2$ as residual symmetry. We show that, under the additional assumptions that the three-dimensional manifold is conformal to a product space $\mathbb{R}\times\Sigma$, and all fields depend only on the coordinate along $\mathbb{R}$, the equations of motion are integrable. This generalizes the results of Leigh et al. in arXiv:1403.6511 to the case where also electromagnetic fields are present. In the second part of the paper we consider the purely gravitational spacetime admitting a second Killing vector that commutes with the timelike one. We write down the resulting two-dimensional action and discuss its symmetries. If the fields depend only on one of the two coordinates, the equations of motion are again integrable, and the solution turns out to be one constructed by Krasinski many years ago.Comment: 24 pages, uses jheppub.sty. v2: Final version to be published in CQ

Duality invariance in Fayet-Iliopoulos gauged supergravity

We propose a geometric method to study the residual symmetries in $N=2$, $d=4$ $\text{U}(1)$ Fayet-Iliopoulos (FI) gauged supergravity. It essentially involves the stabilization of the symplectic vector of gauge couplings (FI parameters) under the action of the U-duality symmetry of the ungauged theory. In particular we are interested in those transformations that act non-trivially on the solutions and produce scalar hair and dyonic black holes from a given seed. We illustrate the procedure for finding this group in general and then show how it works in some specific models. For the prepotential $F=-iX^0X^1$, we use our method to add one more parameter to the rotating Chow-Comp\`ere solution, representing scalar hair.Comment: 31 pages, uses jheppub.sty. Final version to appear on JHE

Illiquidity shocks and the size effect: an event study of liquidity crises.

This paper empirically investigates the impact of liquidity on stock returns during liquidity crises. An event study approach is employed to analyse the behaviour of stock returns around periods of crisis. The focus is set on the different effect of liquidity shocks on large and small/medium caps. Tests for the presence of abnormal returns show that small/medium stocks are negatively affected by crashes in market liquidity, while blue chips performance is not significantly influenced by the crises. The abnormal returns for small caps occur immediately after the liquidity crises and the impact generally lasts for the 15 following trading days. From a buy-and-hold perspective the deviation from the predicted performance can account for up to -1.7%

Renewing a historical legacy: Tourism, leisure shopping and urban branding in Paris

This article discusses a form of urban tourism branding based on the archetypical form of consumerism: leisure shopping. Commodity fetishism is instrumental not only to increasing mainstream fashion sales but also to rejuvenating and multiplying city images on the global competitive market. Drawing from fieldwork performed in Paris, the article analyses and discusses the strategies developed by key players to promote leisure shopping for urban tourists. It specifically focuses on the actions of public-led tourism marketing organisations. Paris is historically renowned as a capital of style and a commercial metropolis, which can easily be used as a basis to develop urban branding strategies for promoting tourism. However, urban branding based on leisure shopping per se was rarely fostered until recently. Previous theoretic reflections on urban development and consumption - leading to debates on the "fantasy city", the "cultural-creative city" and "local shopping streets" - provide the analytical basis for understanding the promotion of leisure shopping as an urban tourism branding strategy in Paris and the changing relations between urban political economy and consumer capitalism

Are we allowed to use fictional vignettes in cultural geographies?

Fictional vignettes are narrative texts that academic researchers may invent in order to illustrate arguments or to present their research outcomes; they are stories or situations that do not strictly report factual realities observed by the author, but that, in any case, implement the heuristics for the arguments that the author wants to raise. Although there are several works in social sciences taking advantage of fictional narratives, geographers have started mobilising invented stories in their writings mostly recently, provided that a variety of creative methodologies had been introduced. The aim of this article is to present fictional vignettes as an integrative research method and writing technique, while discussing potential opportunities and limits relating to their use in geographical research, particularly within the recent rise of various ‘creative methodologies’ in cultural geographies

Questioning Walking Tourism from a Phenomenological Perspective: Epistemological and Methodological Innovations

This article aims to illuminate the overlooked entanglement of space, material practices, affects, and cognitive work emplaced in walking tourism. Walking as a tourism activity is generally practised in the open air away from crowded locations; therefore, it is being encouraged even more in this (post)pandemic era than prior to the pandemic. While walking is often represented as a relatively easy activity in common promotional discourse, this article argues that it is much more complex. It revises the notion of tourist place performance, focusing on walking both as a tourist practice and as a research method that questions multi-sensory and emotional walker engagement. While extensively revisiting literature on walking tourism and the most novel methodological innovations, the article draws from a walking tourism experience undertaken as part of a student trip to demonstrate that the emotions that arise from walkers’ embodied encounters with living, as well as inanimate elements, extend beyond what might be included in a simple focus on landscape “sights”. In conclusion, it is suggested that a phenomenological approach to walking may prove particularly useful for understanding key issues associated with space, place, and tourism mobilities