Statistical mechanics of general discrete nonlinear Schr{\"o}dinger models: Localization transition and its relevance for Klein-Gordon lattices

We extend earlier work [Phys.Rev.Lett. 84, 3740 (2000)] on the statistical mechanics of the cubic one-dimensional discrete nonlinear Schrodinger (DNLS) equation to a more general class of models, including higher dimensionalities and nonlinearities of arbitrary degree. These extensions are physically motivated by the desire to describe situations with an excitation threshold for creation of localized excitations, as well as by recent work suggesting non-cubic DNLS models to describe Bose-Einstein condensates in deep optical lattices, taking into account the effective condensate dimensionality. Considering ensembles of initial conditions with given values of the two conserved quantities, norm and Hamiltonian, we calculate analytically the boundary of the 'normal' Gibbsian regime corresponding to infinite temperature, and perform numerical simulations to illuminate the nature of the localization dynamics outside this regime for various cases. Furthermore, we show quantitatively how this DNLS localization transition manifests itself for small-amplitude oscillations in generic Klein-Gordon lattices of weakly coupled anharmonic oscillators (in which energy is the only conserved quantity), and determine conditions for existence of persistent energy localization over large time scales.Comment: to be published in Physical Review

Prefigurative performance in the age of political deception

The most notable forms of activism in recent years, prefigurative interventions and occupations, are comparable to theatrical performance by embodying, situating and interacting hypothetical scenarios. The mutual points of political performance lies in open-ended, horizontal performance practices such as site-sensitive interventions, tactical media, applied theatre and cognate modes of interactive performance. Whilst several examples of such overlapping performance phenomena are given and justified in the article, the political disciplines also face mutual challenges from hegemonic politics and thus share a need to adapt their performative effects into sustainable social movements

Interdisciplinary strate in applied performance and activism

The paper addresses the challenges and advantages of collaborative stratification in the continuum of theatre and fine arts, with examples from applied performance projects in international contexts. With different approaches to performance/media, acting/agency, devising/curatorship and participation/social engagement, collaborative processes have proved to be quite incongruent in method and motif, although inclusive and versatile in media tactics and political outreach. In post-Brechtian theatre the critical impetus of context always carry as much meaning as ostensive character relations, a force field which is exemplified in the co-extensive performativity of applied theatre and institutional critique in the cases presented in the paper. Three collaborative projects led by Ola Johansson (Reader in Contemporary Performance Practice, Middlesex University) and Amanda Newall (Senior Lecturer in Fine Art, Royal Institute of Art, Stockholm) will be discussed: (1) an activist performance against an IKEA store with the American performance/media group The Yes Men; (2) a bio-arts performance/video work about post-colonial Western Australia; and (3) a theatre production about male privilege in Sweden and South Africa. In all three projects Newall’s use of costume, material objects and visual effects stand in paratactical relations to Johansson’s devised processes with the intent to open a third space where so-called ‘emancipated spectators’ (Rancière) either need to take action (à la ‘spectactors’) or remain passive although on a conceptually shared stage with the performers. By tracing the educational legacy of performance art (John Dewey’s creative democracy) and applied theatre (Paolo Freire’s participatory pedagogy) and its subsequent artistic initiatives to activate the chasm between performer and spectator (conceptualized simultaneously although independently by Allan Kaprow and Augusto Boal), the paper will pursue interdisciplinary genealogies of performance research but also revive a discourse on political efficacy in applied performance

The limits of community-based theatre: performance and HIV prevention in Tanzania

A research project on community-based theatre in Tanzania questions the efficacy of the genre in combating the AIDS epidemic. If performances are well attended, and participants are informed on the causes of the virus, why is it still rampant? Efficacy will be possible only when gender inequities and taboos are openly confronted

"It's the real thing": performance and murder in Sweden.

The article investigates contemporary experimental theatre in Sweden. It sums up and probes the implications of Sju tre (1999), the most controversial theatre production in Sweden in modern times. Lars Nor'n, the playwright and director, staged a dialogue involving three real convicts, of whom two were outspoken Nazis. The article explores the uncertain boundaries between aesthetic, ethical, and political issues with ramifications regarding the wider public opinion in Sweden, on racism and crime. It is methodologically motivated by reception research, performativity and idealogical discourse. By virtue of its performative impact, the theatrical event proved to be directly linked with critical questions of democracy, although conceivably at the expense of the artistic integrity of the director and the theatre as creator of public opinion. The article points to a paradox of democracy whereby hate speech is at once allowed and unjustified in the theatre as national arena. The actors are described and analysed as parasites in a societal body, that in Sju tre, becomes politically epitomised