Parton theory of magnetic polarons: Mesonic resonances and signatures in dynamics

When a mobile hole is moving in an anti-ferromagnet it distorts the surrounding Neel order and forms a magnetic polaron. Such interplay between hole motion and anti-ferromagnetism is believed to be at the heart of high-Tc superconductivity in cuprates. We study a single hole described by the t-Jz model with Ising interactions between the spins in 2D. This situation can be experimentally realized in quantum gas microscopes. When the hole hopping is much larger than couplings between the spins, we find strong evidence that magnetic polarons can be understood as bound states of two partons, a spinon and a holon carrying spin and charge quantum numbers respectively. We introduce a microscopic parton description which is benchmarked by comparison with results from advanced numerical simulations. Using this parton theory, we predict a series of excited states that are invisible in the spectral function and correspond to rotational excitations of the spinon-holon pair. This is reminiscent of mesonic resonances observed in high-energy physics, which can be understood as rotating quark antiquark pairs. We also apply the strong coupling parton theory to study far-from equilibrium dynamics of magnetic polarons observable in current experiments with ultracold atoms. Our work supports earlier ideas that partons in a confining phase of matter represent a useful paradigm in condensed-matter physics and in the context of high-Tc superconductivity. While direct observations of spinons and holons in real space are impossible in traditional solid-state experiments, quantum gas microscopes provide a new experimental toolbox. We show that, using this platform, direct observations of partons in and out-of equilibrium are possible. Extensions of our approach to the t-J model are also discussed. Our predictions in this case are relevant to current experiments with quantum gas microscopes for ultracold atoms.Comment: 30 pages, 4 appendices, 26 figure

A bekiabálás vizsgálata mimetikus és személyközi nézőpontból

The present paper aims to model the interactional operation of heckling, which has received little attention in impoliteness and interaction studies, despite the fact that studying this phenomenon has various advantages for the analyst. In order to fill this knowledge gap, we approach heckling by combining Turner’s (1982) anthropological framework with Kádár’s interaction-based relational ritual theory (e.g. Kádár 2012, 2013; Kádár & Bax 2013). Following Turner, we define heckling as a ‘social drama’, which is evaluated by its watchers as ‘judges’. In accordance with Kádár’s relational ritual framework we argue that heckling is a mimetic ritualistic mini-performance, which is inherently interactional as it operates in the adjacent action pair of the heckler’s performance and the public speaker/performer’s counter-performance. Adopting Turner’s terminology, heckling is a ritualistic performance of ‘anti-structure’, i.e. it upsets the regular social – and consequently interactional – structure of a setting. Successful counter-performance is a ritual of ‘structure’, which restores the normal social structure of the event, as the public speaker/performer regains control over the interaction. Through the social actions of performance and counter-performance the heckled and the heckler aim to affiliate themselves with the audience, who are ‘metaparticipants’ of the ritualistic interaction, and with the watchers/listeners in the case of video/audio-recorded interactions, who can be defined as ‘lay observers’ (cf. Kádár & Haugh 2013). Approaching heckling as a theatrical type of relational ritual helps us capture various complexities of this phenomenon, such as its relationship with certain interactional settings and metaparticipant expectations/ evaluations, and its interface with related phenomena such as impoliteness

Group authorship, an excellent opportunity laced with ethical, legal and technical challenges

Group authorship (also known as corporate authorship, team authorship, consortium authorship) refers to attribution practices that use the name of a collective (be it team, group, project, corporation, or consortium) in the authorship byline. Data shows that group authorships are on the rise but thus far, in scholarly discussions about authorship, they have not gained much specific attention. Group authorship can minimize tensions within the group about authorship order and the criteria used for inclusion/exclusion of individual authors. However, current use of group authorships has drawbacks, such as ethical challenges associated with the attribution of credit and responsibilities, legal challenges regarding how copyrights are handled, and technical challenges related to the lack of persistent identifiers (PIDs), such as ORCID, for groups. We offer two recommendations: 1) Journals should develop and share context-specific and unambiguous guidelines for group authorship, for which they can use the four baseline requirements offered in this paper; 2) Using persistent identifiers for groups and consistent reporting of members’ contributions should be facilitated through devising PIDs for groups and linking these to the ORCIDs of their individual contributors and the Digital Object Identifier (DOI) of the published item.</p