Neighbourhoodies: courageous community, colours, blazing bling and defiant delight

As we see a global culture appear across the planet identity politics simultaneously gravitate towards issues of the local. In society’s top strata people strive to live in posh areas with the right postal code. Subversive counterculture activists try to keep their own multi-ethnic spaces free from yuppies who in turn try to gentrify the same areas into authentic bohemian-chic quarters. In the urban fringes gangs protect their territory and even tattoo their hood names as a sign of authentic pride. Caught in the line of fire of identity politics is the hoodie, an average street-style garment, the canvas on which social conflicts and criminal stigmata are drawn, but also where local pride and reconciliation can be brought about, inspired by its connection to the resonance of musical milieus. In a time of liquid consumerism and fear, the habitus of the hoodie seems to frame a problematic identity which has been exposed in the ban on such garments in some British malls. The Neighburhoodies expands on a practice-based endeavour where fashion students from London College of Fashion reflected on their glocal London identities through the design of a special hoodie - a Neighbourhoodie

On the Sharpness and Bias of Quantum Effects

The question of quantifying the sharpness (or unsharpness) of a quantum mechanical effect is investigated. Apart from sharpness, another property, bias, is found to be relevant for the joint measurability or coexistence of two effects. Measures of bias will be defined and examples given.Comment: Substantially expanded version, with new results and some proofs correcte

Perfect correlations between noncommuting observables

The problem as to when two noncommuting observables are considered to have the same value arises commonly, but shows a nontrivial difficulty. Here, an answer is given by establishing the notion of perfect correlations between noncommuting observables, and applied to obtain a criterion for precise measurements of a given observable in a given state.Comment: 7 pages, Revtex4, v3: added a section on conventional models of measurement

Fashion-able. Hacktivism and engaged fashion design

This thesis consists of a series of extensive projects which aim to explore a new designer role for fashion. It is a role that experiments with how fashion can be reverse engineered, hacked, tuned and shared among many participants as a form of social activism. This social design practice can be called the hacktivism of fashion. It is an engaged and collective process of enablement, creative resistance and DIY practice, where a community share methods and experiences on how to expand action spaces and develop new forms of craftsmanship. In this practice, the designer engages participants to reform fashion from a phenomenon of dictations and anxiety to a collective experience of empowerment, in other words, to make them become fashion-able. As its point of departure, the research takes the practice of hands-on exploration in the DIY upcycling of clothes through “open source” fashion “cookbooks”. By means of hands-on processes, the projects endeavour to create a complementary understanding of the modes of production within the field of fashion design. The artistic research projects have ranged from DIY-kits released at an international fashion week, fashion experiments in galleries, collaborative “hacking” at a shoe factory, engaged design at a rehabilitation centre as well as combined efforts with established fashion brands. Using parallels from hacking, heresy, fan fiction, small change and professional-amateurs, the thesis builds a non-linear framework by which the reader can draw diagonal interpretations through the artistic research projects presented. By means of this alternative reading new understandings may emerge that can expand the action spaces available for fashion design. This approach is not about subverting fashion as much as hacking and tuning it, and making its sub-routines run in new ways, or in other words, bending the current while still keeping the power on

The Standard Model of Quantum Measurement Theory: History and Applications

The standard model of the quantum theory of measurement is based on an interaction Hamiltonian in which the observable-to-be-measured is multiplied with some observable of a probe system. This simple Ansatz has proved extremely fruitful in the development of the foundations of quantum mechanics. While the ensuing type of models has often been argued to be rather artificial, recent advances in quantum optics have demonstrated their prinicpal and practical feasibility. A brief historical review of the standard model together with an outline of its virtues and limitations are presented as an illustration of the mutual inspiration that has always taken place between foundational and experimental research in quantum physics.Comment: 22 pages, to appear in Found. Phys. 199

A note on the Pauli problem in light of approximate joint measurements

We show that there exist informationally incomplete phase space observables such that the Cartesian margins are informationally equivalent with position and momentum. This shows that it is possible to reconstruct the position and momentum distributions of a quantum system from the statistics of a single observable, and thus a single measurement, even though the state of the system is not uniquely determined by the statistics.Comment: 12 page

The quantum measurement problem enhanced

The quantum measurement problem as formalised by Bassi and Ghirardi [Phys. Lett. A 275 (2000)373] without taking recourse to sharp apparatus observables is extended to cover impure initial states.Comment: 6 page

On the complementarity of the quadrature observables

In this paper we investigate the coupling properties of pairs of quadrature observables, showing that, apart from the Weyl relation, they share the same coupling properties as the position-momentum pair. In particular, they are complementary. We determine the marginal observables of a covariant phase space observable with respect to an arbitrary rotated reference frame, and observe that these marginal observables are unsharp quadrature observables. The related distributions constitute the Radon tranform of a phase space distribution of the covariant phase space observable. Since the quadrature distributions are the Radon transform of the Wigner function of a state, we also exhibit the relation between the quadrature observables and the tomography observable, and show how to construct the phase space observable from the quadrature observables. Finally, we give a method to measure together with a single measurement scheme any complementary pair of quadrature observables.Comment: Dedicated to Peter Mittelstaedt in honour of his eightieth birthda

Associations between stress and migraine and tension-type headache: Results from a school-based study in adolescents from grammar schools in Germany

Introduction: Stress is considered the major contributor to migraine and tension-type headache in adolescents. Previous studies have focused on general stressors, whereas the aim of the present study was to investigate associations between individuals’ stressful experiences and different types of headache. Methods: Adolescents from 10th and 11th grades of grammar schools filled in questionnaires. Stressful experiences were measured with the Trier Inventory of Chronic Stress. Type of headache was classified according to the International Classification of Headache Disorders. Linear regressions, adjusted for sex and grade, were calculated to estimate differences in stress scores that can be attributed to migraine, tension-type headache or miscellaneous headache. Results: A total of 1260 questionnaires were analysed. Tension-type headache, migraine and co-existing migraine plus tension-type headache were found in 48.7%, 10.2% and 19.8% of the participants. In subjects with migraine or co-existing migraine plus tension-type headache, high increases in stress scores were found in all investigated dimensions, whereas much weaker and inconsistent associations were found in subjects with tension-type headache only. Conclusions: The characteristic of migraine is more associated with stressful experiences than this is the case for tensiontype headache. This suggests that adolescent migraine patients might specially benefit from behavioural interventions regarding stress

Transferring elements of a density matrix

We study restrictions imposed by quantum mechanics on the process of matrix elements transfer. This problem is at the core of quantum measurements and state transfer. Given two systems \A and \B with initial density matrices $\lambda$ and $r$, respectively, we consider interactions that lead to transferring certain matrix elements of unknown $\lambda$ into those of the final state ${\widetilde r}$ of \B. We find that this process eliminates the memory on the transferred (or certain other) matrix elements from the final state of \A. If one diagonal matrix element is transferred, ${\widetilde r}_{aa}=\lambda_{aa}$, the memory on each non-diagonal element $\lambda_{a\not=b}$ is completely eliminated from the final density operator of \A. Consider the following three quantities \Re \la_{a\not =b}, \Im \la_{a\not =b} and \la_{aa}-\la_{bb} (the real and imaginary part of a non-diagonal element and the corresponding difference between diagonal elements). Transferring one of them, e.g., \Re\tir_{a\not = b}=\Re\la_{a\not = b}, erases the memory on two others from the final state of \A. Generalization of these set-ups to a finite-accuracy transfer brings in a trade-off between the accuracy and the amount of preserved memory. This trade-off is expressed via system-independent uncertainty relations which account for local aspects of the accuracy-disturbance trade-off in quantum measurements.Comment: 9 pages, 2 table