A Birkhoff connection between quantum circuits and linear classical reversible circuits

Birkhoff's theorem tells how any doubly stochastic matrix can be decomposed as a weighted sum of permutation matrices. Similar theorems on unitary matrices reveal a connection between quantum circuits and linear classical reversible circuits. It triggers the question whether a quantum computer can be regarded as a superposition of classical reversible computers

Vacuum block thermalization in semi-classical 2d CFT

The universal nature of black hole collapse in asymptotically $AdS_3$ gravitational theories suggests that its holographic dual process, thermalization, should similarly be fixed by the universal features of 2d CFT with large central charge $c$. It is known that non-equilibrium states with scaling dimensions of order $c$ can be sorted into states that eventually thermalize and those that fail to do so. By proving an equivalence between bounded Virasoro coadjoint orbits and certain (in)stability intervals of Hill's equation it is shown that a state that fails to thermalize can be promoted to a thermalizing state by preparing the system beforehand with an energy greater than an appropriate threshold energy. It is generally a difficult problem to ascertain whether a state will thermalize or not. As partial progress to this problem a set of lower bounds are presented for the treshold energy, which can alternatively be interpreted as criteria for thermalization.Comment: 1 figure, 31 pages, v2: fixed typos, added reference

SiLC simulation status report

The SiLC - Silicon for the Linear Collider - collaboration aims to develop silicon detector technology for tracking in the international linear collider experiments. The R & D programme involves a substantial effort in simulation of the response of detector designs. In this contribution, an overview of ongoing efforts in this area is given.Comment: proceedings of LCWS0

Structure of, access to, and uncertainty in reasoning and their dependence on content

It is known that content has an effect on reasoning. In this paper the influence of the content on the structure of reasoning, the access to it, and the ability to handle uncertainty was studied. The participants were presented with reasoning tasks about the weather and about the oscilloscope in which uncertain premises were introduced. Correct reasoning procedures were identified including correct reasoning with wrong answers. In correct reasoning procedures about the weather, three different structures of reasoning were identified. The participants were mostly able to reason with uncertain components. In reasoning about the oscilloscope, less correct reasoning procedures were found. No empirical and theoretical structures were used. The hidden structure differed here from the one in the weather case because the participants were not able to handle all uncertain components in otherwise correct reasoning. The implications of this unique finding for the acquisition of reasoning skills are discusse

The Belgian paradox: high EU profile, low EU interest

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Coffee, cash, and consumption: rethinking commodity production in the global south

This essay reflects on the study of coffee production in Angola, following research in business and missionary archives in the Netherlands and the United Kingdom. After observing that African coffee farmers were consumers of foreign goods as much as they were producers for the global market, the essay makes a case for tying histories of consumption into histories of labor and production. It suggests there were long-term continuities as well as changes in African consumption patterns. Finally, it underlines the importance of studying the history of labor and consumption in Africa outside the traditional framework of colonial history, focusing instead on the global dimensions of commodity production

Metacognition and transfer within a course or instructional design rules and metacognition

A metacognitive strategy for doing research, included transfer, was taught in a course of nine afternoons. The success of this course raised some questions. How do the students learn? How does metacognition play a role? The course was designed in accordance with several instructional principles. The course was divided into three domains in which the strategy was introduced, practised, and applied respectively. Literature research revealed four possible metacognitive variants that correlate so it was supposed that implementing them all helped to reach the objectives of the course. The relation of the metacognitive variants with the instructional principles is described. To study learning the students were divided into three groups (weak, moderate, good) by their marks for other courses. The performance of the groups in each domain was monitored by their marks, scoring of metacognitive skills, questionnaires, observations, and time keeping. The moderate students scored as high as the good ones for the strategy in the last domain, a unique result. The metacognitive development of the other metacognitive skills was not linear. The conclusions are that the success of this course can be explained by a system of double sequencing and an interaction of all metacognitive variants, and that instructional design rules for metacognitive and cognitive objectives are differen

An active learning organisation: teaching projects in electrical engineering education

The introduction of active learning in engineering education is often started by enthusiastic teachers or change agents. They usually encounter resistance from stakeholders such as colleagues, department boards or students. For a successful introduction these stakeholders all have to learn what active learning involves for them. This means that active learning has to take place on three levels: the students, the staff, and the organisation. These three actors have each to learn from experience, and their learning processes have to be related. Learning on the lowest level is based on the cycle of Kolb for experiential learning. If learning is seen as a form of change, similar cycles can be distinguished for learning on the levels of the staff and the organisation. On the staff level a model of Van Delden's for influencing staff members is used. For organisational change some ideas about the learning organisation from Senge are adapted to educational organisations like departments. A comprehensive view on student learning, staff development, and organisational learning is presented. The model includes four aspects of learning on three levels of educational actors and the relations among them. This model can be an illuminating guide for the introduction and/or general acceptance of active learning at your institution as a lasting change

Top-quark mass measurements at the LHC: alternative methods

Alternative top quark mass determinations can provide inputs to the world average with orthogonal systematic uncertainties and may help to refine the interpretation of the standard method. Among a number of recent results I focus on the extractions by ATLAS and CMS of the top quark pole mass from the top quark pair and tt + 1 jet production cross-section, which have now reached a precision of 1%