119 research outputs found
âWarrantâ revisited: Integrating mathematics teachersâ pedagogical and epistemological considerations into Toulminâs model for argumentation
In this paper, we propose an approach to analysing teacher arguments that takes into account field dependenceânamely, in Toulminâs sense, the dependence of warrants deployed in an argument on the field of activity to which the argument relates. Freeman, to circumvent issues that emerge when we attempt to determine the field(s) that an argument relates to, proposed a classification of warrants (a priori, empirical, institutional and evaluative). Our approach to analysing teacher arguments proposes an adaptation of Freemanâs classification that distinguishes between: epistemological and pedagogical a priori warrants, professional and personal empirical warrants, epistemological and curricular institutional warrants, and evaluative warrants. Our proposition emerged from analyses conducted in the course of a written response and interview study that engages secondary mathematics teachers with classroom scenarios from the mathematical areas of analysis and algebra. The scenarios are hypothetical, grounded on seminal learning and teaching issues, and likely to occur in actual practice. To illustrate our proposed approach to analysing teacher arguments here, we draw on the data we collected through the use of one such scenario, the Tangent Task. We demonstrate how teacher arguments, not analysed for their mathematical accuracy only, can be reconsidered, arguably more productively, in the light of other teacher considerations and priorities: pedagogical, curricular, professional and personal
Resonant nature of phonon-induced damping of Rabi oscillations in quantum dots
Optically controlled coherent dynamics of charge (excitonic) degrees of
freedom in a semiconductor quantum dot under the influence of lattice dynamics
(phonons) is discussed theoretically. We show that the dynamics of the lattice
response in the strongly non-linear regime is governed by a semiclassical
resonance between the phonon modes and the optically driven dynamics. We stress
on the importance of the stability of intermediate states for the truly
coherent control.Comment: 4 pages, 2 figures; final version; moderate changes, new titl
Practising Mathematics Teacher Education: Expanding The Realm of Possibilities
It is often said that student teachersâ underlying beliefs of what mathematics consists of and how it should be taught are restricted in two ways. On the one hand, future elementary teachers in general use only weak mathematical conceptions, which often do not help them to realise their educational ambitions. On a general educational level, many of these students advocate discovery learning and collective problem solving, but when it comes down to the mathematical activities that have to be prepared, their experience of âtraditionalâ school mathematics is of little help. On the other hand, future (higher) secondary teachers mostly are very well prepared with respect to formal academic mathematics when entering mathematics education programmes, either because they have already passed a mathematical formation at university or because their teacher education programmes emphasise the study of academic mathematics and not of educational or didactical modules
Measurement of Two-Qubit States by a Two-Island Single Electron Transistor
We solve the master equations of two charged qubits measured by a
single-electron transistor (SET) consisted of two islands. We show that in the
sequential tunneling regime the SET current can be used for reading out results
of quantum calculations and providing evidences of two-qubit entanglement,
especially when the interaction between the two qubits is weak
'Don't think in your head, think aloud': ICT and exploratory talk in the primary school mathematics classroom
This paper arises out of research into classroom activities conducted with Year 5 and Year 6 primary school students (9-10 year-olds). The study applied the âThinking Togetherâ approach developed by Mercer and colleagues at the Open University in mathematics lessons involving the use of ICT. The study describes the use of mathematics software to promote collaborative thinking and exploratory talk in the mathematics classroom. Teachers were given training in the Thinking Together approach. They then conducted a series of lessons with students and explicitly taught them how to work and talk collaboratively to solve mathematical problems at the computer. These lessons were video-recorded and the transcripts analysed for evidence of âexploratory talkâ. This paper reports on the role of the teacher, the students and the computer in developing exploratory talk
Spin-based all-optical quantum computation with quantum dots: understanding and suppressing decoherence
We present an all-optical implementation of quantum computation using
semiconductor quantum dots. Quantum memory is represented by the spin of an
excess electron stored in each dot. Two-qubit gates are realized by switching
on trion-trion interactions between different dots. State selectivity is
achieved via conditional laser excitation exploiting Pauli exclusion principle.
Read-out is performed via a quantum-jump technique. We analyze the effect on
our scheme's performance of the main imperfections present in real quantum
dots: exciton decay, hole mixing and phonon decoherence. We introduce an
adiabatic gate procedure that allows one to circumvent these effects, and
evaluate quantitatively its fidelity
AlltagspÀdagogik in mathematischen Spielsituationen mit Vorschulkindern
Tiedemann K, Brandt B. AlltagspĂ€dagogik in mathematischen Spielsituationen mit Vorschulkindern. In: Brandt B, Vogel R, Krummheuer G, eds. Die Projekte erStMaL und MaKreKi. Mathematikdidaktische Forschung am âCenter for Individual Development and Adaptive Educationâ (IDeA). MĂŒnster: Waxmann; 2011: 91-134
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