Exciton formation in strongly correlated electron-hole systems near the semimetal-semiconductor transition

The region surrounding the excitonic insulator phase is a three-component plasma composed of electrons, holes, and excitons. Due to the extended nature of the excitons, their presence influences the surrounding electrons and holes. We analyze this correlation. To this end, we calculate the density of bound electrons, the density of electrons in the correlated state, the momentum-resolved exciton density, and the momentum-resolved density of electron-hole pairs that are correlated but unbound. We find qualitative differences in the electron-hole correlations between the weak-coupling and the strong-coupling regime.Comment: 10 pages, 5 figure

Electron-hole pair condensation at the semimetal-semiconductor transition: a BCS-BEC crossover scenario

We act on the suggestion that an excitonic insulator state might separate---at very low temperatures---a semimetal from a semiconductor and ask for the nature of these transitions. Based on the analysis of electron-hole pairing in the extended Falicov-Kimball model, we show that tuning the Coulomb attraction between both species, a continuous crossover between a BCS-like transition of Cooper-type pairs and a Bose-Einstein condensation of preformed tightly-bound excitons might be achieved in a solid-state system. The precursor of this crossover in the normal state might cause the transport anomalies observed in several strongly correlated mixed-valence compounds.Comment: 5 pages, 5 figures, substantially revised versio

Resumptive pronouns facilitate processing of long-distance relative clause dependencies in second language English

This study provides evidence that resumptive pronouns (RPs) can facilitate the processing of long-distance subject relative clause (RC) dependencies during second language (L2) sentence comprehension, even where they are disallowed in both the first language (L1) and the target language. A test group of 29 L1-Korean L2 learners (L2ers) of English and a control group of 25 native English speakers completed an online self-paced reading task (SPRT) and an offline acceptability judgment task (AJT) designed to test whether RPs reflect Interlanguage grammar representations and/or a strategy to alleviate processing overload. Analysis of the SPRT data from both response times and comprehension question accuracy indicates that RPs assisted the L2ers, but not the native speakers, with dependency resolution in long-distance RCs. For the AJT data, a proficiency effect was observed whereby some lower-proficiency L2ers, but not the higher-proficiency ones or the native speakers, tended to prefer RPs over gaps in long-distance RCs. The implications of these findings and plans for future research are discussed

Slave-boson field fluctuation approach to the extended Falicov-Kimball model: charge, orbital, and excitonic susceptibilities

Based on the SO(2)-invariant slave-boson scheme, the static charge, orbital, and excitonic susceptibilities in the extended Falicov-Kimball model are calculated. Analyzing the phase without long-range order we find instabilities towards charge order, orbital order, and the excitonic insulator (EI) phase. The instability towards the EI is in agreement with the saddle-point phase diagram. We also evaluate the dynamic excitonic susceptibility, which allows the investigation of uncondensed excitons. We find qualitatively different features of the exciton dispersion at the semimetal-EI and at the semiconductor-EI transition supporting a crossover scenario between a BCS-type electron-hole condensation and a Bose-Einstein condensation of preformed bound electron-hole pairs.Comment: 8 pages, 9 figures, final versio

A probabilistic analysis of argument cogency

This paper offers a probabilistic treatment of the conditions for argument cogency as endorsed in informal logic: acceptability, relevance, and sufficiency. Treating a natural language argument as a reason-claim-complex, our analysis identifies content features of defeasible argument on which the RSA conditions depend, namely: change in the commitment to the reason, the reason’s sensitivity and selectivity to the claim, one’s prior commitment to the claim, and the contextually determined thresholds of acceptability for reasons and for claims. Results contrast with, and may indeed serve to correct, the informal understanding and applications of the RSA criteria concerning their conceptual dependence, their function as update-thresholds, and their status as obligatory rather than permissive norms, but also show how these formal and informal normative approachs can in fact align

Post-holiday memory work: Everyday encounters with fridge magnets

While souvenirs have generated considerable interest within tourism research, less attention has been paid to their post-holiday ‘afterlife’. Utilising perspectives from memory research and more-than-representational theory, this paper focuses on interactions with a ubiquitous souvenir: the fridge magnet. Drawing on semi-structured interviews we illustrate how, because of their embeddedness within everyday domestic rhythms, magnets are active agents in the stimulation of post-holiday memory work. We show how magnets work to generate and protect memories, triggering a diversity of (usually positive) emotional and affective responses. They can also be associated with ambivalent memories; with their role sometimes being more about forgetting. Although being seemingly banal objects, fridge magnets have a complex capacity to affect everyday life long after a holiday ends

Place branding: Are we wasting our time? Report of an AMA special session

© Emerald Group Publishing Limited.Purpose – The purpose of this paper is to report on a special session entitled “Place branding: Are we wasting our time?”, held at the American Marketing Association’s Summer Marketing Educators’ conference in 2014. Design/methodology/approach – The report details the outcome of an Oxford-style debate with two opposing teams of two persons – one team supporting and one team opposing the motion. The opening speaker of each team had 10 minutes to put their case across, and the closing speaker had 8 minutes. Teams took to the stand alternately, matching up against each other’s arguments. Findings – The outcome of the debate points towards a need for place brands to develop as more inclusive and organic entities, in which case it may be best for place practitioners to avoid creating and imposing a place brand and instead help shape it from the views of stakeholder constituencies. This shifts the notion of place branding towards an activity centred on “curation”. Originality/value – The use of a competitive debating format as a means for exploring academic ideas and concepts in the place management field