On ground state phases of quantum spin systems

In this short note, I review some recent results about gapped ground state phases of quantum spin systems and discuss the notion of topological order.Comment: Note written for the News Bulletin of the International Association of Mathematical Physics (IAMP); IAMP News Bulletin, July 201

Ambivalent pasts: colonial history and the theatricalities of ethnographic display

In the twenty-first century, museums holding ethnographic collections have come under scrutiny for their implication in colonial history, and many have started to address this problematic legacy, often in conscious attempts to move beyond the colonial as “post-ethnographic” spaces and forums for intercultural dialogue. This essay uses a contemporary artwork, Peggy Buth’s installation “The Warrior as Multiple, “exhibited at the Frankfurt Museum of World Cultures in 2014, as a starting point to develop a taxonomy of dominant curatorial strategies at work in ethnographic museums today: self-reflexive contextualization, inversion or reversal, indigenous curation, visible storage, and the turn to live performance—all of which are used to address colonial history. Approaching these strategies from the perspective of theatre and performance studies, the essay analyzes their “theatricalities” of display—the “doing” of ethnographic objects, as well as the “spectacularity” of dioramic settings—through a series of case studies, including the American Museum of Natural History in New York City, the Mashantucket Pequot Museum and Research Center in Connecticut, and the Tropenmuseum Amsterdam. It argues that despite their critical potential, these strategies run the danger of being complicit in a working through (in the Freudian sense of the term) of colonial history, which might ultimately “liberate” ethnographic museums from their problematic legacy. Instead, the essay proposes an insistence on ambivalence, understood as the simultaneous co-existence of at least two conflicting meanings, in order to resist such an erasure

Statistical Analysis of Structural Transitions in Small Systems

We discuss general thermodynamic properties of molecular structure formation processes like protein folding by means of simplified, coarse-grained models. The conformational transitions accompanying these processes exhibit similarities to thermodynamic phase transitions, but also significant differences as the systems that we investigate here are very small. The usefulness of a microcanonical statistical analysis of these transitions in comparison with a canonical interpretation is emphasized. The results are obtained by employing sophisticated generalized-ensemble Markov-chain Monte Carlo methodologies.Comment: 9 pages, 5 figures, Proceedings of the 22nd Workshop on Recent Developments in Computer Simulation Studies in Condensed Matter Physics, Feb 23-27, 2009, Athens, Georgia, US

Interpolated Schur multiple zeta values

Inspired by a recent work of M. Nakasuji, O. Phuksuwan and Y. Yamasaki we combine interpolated multiple zeta values and Schur multiple zeta values into one object, which we call interpolated Schur multiple zeta values. Our main result will be a Jacobi-Trudi formula for a certain class of these new objects. This generalizes an analogous result for Schur multiple zeta values and implies algebraic relations between interpolated multiple zeta values.Comment: 21 page

Wanna Play? Dries Verhoeven and the Limits of Non-Professional Performance

In October 2014, Berlin’s Hebbel am Ufer (HAU)—one of Germany’s most influential performance venues, programming and often co-producing work by artists such as Rimini Protokoll, Jérôme Bel, Meg Stuart and Gob Squad—opened its new season with a festival called Treffpunkte (meeting points).1 Conceptually, the month-long festival was located at the intersection of some of the major trends in contemporary Western theatre and performance, particularly the interest ‘in curating intimacy in public’ (Walsh 2014: 57; Read 2008), the renegotiation of theatre’s place in the public sphere (Balme 2014; Haedicke 2013) and the relation of socially engaged performance, in the broadest sense, to late global capitalism (Jackson 2011; Harvie 2013). Its explicit aim was to explore, through the means of performance, ‘the status of the private in the public sphere’ (den Status des Privaten in der öffentlichen Sphäre) and to find out whether ‘intimacy’ (Intimität)—equated with an authentic ‘communication between people’ (Kommunikation zwischen Menschen)—was still possible ‘in an age where the public space has been entirely pervaded by market conformity’ (im Zeitalter der totalen Durchdringung des öffentlichen Raumes durch das Marktförmige) (Vanackere 2014: 2).

Not out of context: Eric Magassa's 'The Lost' series

The article analyses a series of contemporary photographs by Swedish multi-disciplinary artist Eric Magassa and places them within the larger context of postcolonial practice. Focusing on Magassa's use of masks and the relationship, in his photographs, between sitter and environment, it argues that the political value of his work is to disrupt colonial legacies of Modernist thinking