813 research outputs found
Die menswording van ons menswees ('n studie in die wysgerige antropologie)
Die eerste twee sinne van die bekende Geschonden Wereld van wyle prof. Huizinga lees soos volg: „Wij leven in een bezeten wereld. En wij weten het”. Hierdie stellinge, so kategories as wat hulle geformuleer is, bevat waardevolle materiaal vir wysgerige ontleding, veral in antropologies- aksiologies-etiese opsig. Nou gaan dit in hierdie bydrae aller- mins om ’n sistematiese oopdenking van die genoemde mo- mente. Tog wil die skrywer hiervan by wyse van inleiding tot die onderhawige studie regstreeks daarby aansluit en on- regstreeks telkens daarna verwys
Positive Cross Correlations in a Normal-Conducting Fermionic Beam Splitter
We investigate a beam splitter experiment implemented in a normal conducting
fermionic electron gas in the quantum Hall regime. The cross-correlations
between the current fluctuations in the two exit leads of the three terminal
device are found to be negative, zero or even positive depending on the
scattering mechanism within the device. Reversal of the cross-correlations sign
occurs due to interaction between different edge-states and does not reflect
the statistics of the fermionic particles which `antibunch'.Comment: 4 pages, 4 figure
Ehrenfest-time dependence of weak localization in open quantum dots
Semiclassical theory predicts that the weak localization correction to the
conductance of a ballistic chaotic cavity is suppressed if the Ehrenfest time
exceeds the dwell time in the cavity [I. L. Aleiner and A. I. Larkin, Phys.
Rev. B {\bf 54}, 14424 (1996)]. We report numerical simulations of weak
localization in the open quantum kicked rotator that confirm this prediction.
Our results disagree with the `effective random matrix theory' of transport
through ballistic chaotic cavities.Comment: 4 pages, 2 figure
Dynamic generation of orbital quasiparticle entanglement in mesoscopic conductors
We propose a scheme for dynamically creating orbitally entangled
electron-hole pairs through a time-dependent variation of the electrical
potential in a mesoscopic conductor. The time-dependent potential generates a
superposition of electron-hole pairs in two different orbital regions of the
conductor, a Mach-Zehnder interferometer in the quantum Hall regime. The
orbital entanglement is detected via violation of a Bell inequality, formulated
in terms of zero-frequency current noise. Adiabatic cycling of the potential,
both in the weak and strong amplitude limit, is considered.Comment: 4 pages, 2 figures; references update
UCET Discussion paper on effective Continuing Professional Development
This report is based on the wealth of experience and scholarship shared by UCET colleagues. It reflects on key aspects of CPD-related policy, practice and research over the past 50 years and highlights the following principles:
- Education professionals require an expanding range of competences over their career; these are often context-specific, unforeseen and go beyond any single framework
- As well as being research-informed, CPD should engage educators in theory so they can adapt their learning creatively to enrich their own setting
- Reflective practitioners are best cultivated by supporting teachers’ in conducting their own research
- Effective CPD is built on trusted relationships between deliverers and learners and include a strong element of coaching and/or mentoring often by peers
- For sustained impact, CPD needs to be sustained over time (at least across two terms), making use of multiple formats
- By engaging teachers in their wider social, economic and environmental contexts, CPD will ensure responsible professionals in the fullest sense
- Developing teachers’ agency will enable them to consider their practice critically, lead their own learning and thus maximise the positive impact they have on their learners
- All CPD should be subject to robust quality assurance mechanisms
Shot noise of series quantum point contacts intercalating chaotic cavities
Shot noise of series quantum point contacts forming a sequence of cavities in
a two dimensional electron gas are studied theoretically and experimentally.
Noise in such a structure originates from local scattering at the point
contacts as well as from chaotic motion of the electrons in the cavities. We
found that the measured shot noise is in reasonable agreement with our
theoretical prediction taking the cavity noise into account.Comment: 4 pages, 5 figure
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