21 research outputs found
Discussion with Local Novelists (2022-03-15)
No full textEveryone is creative; Everyone can write; Keith Loveland, author, The End of the Empire; Sarah Seidelmann, author, Where the Deer Dream; Tuesday, 15th March 2022; 6:00 to 7:00 PM; Montague Hall 70; Door prizes & signed books for salePlease join UMD's Cultural Entrepreneurship (CUE) program to learn about the creative writing process of two local authors, Keith Loveland and Sarah Seidelmann. What can you learn about yourself and your own creativity from them?University of Minnesota Duluth. Cultural Entrepreneurship Program. (2022). Discussion with Local Novelists (2022-03-15). Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/227561
Generating and manipulating non-classical states of light in various quantum dot-cavity setups
No full textYoung dyslexic children in the English classroom
No full textDie vorliegende Dissertation verfolgt das Anliegen, die Lernweisen legasthener Schülerinnen und Schüler sowie deren Vorschläge und Ideen zu einer anderen Gestaltung des Unterrichts in einer frühen Phase des Zweitspracherwerbs zu erfassen und in einem ganzheitlichen Konzept umzusetzen. Ziel war es, aus Erkenntnissen, die maßgeblich auf Aussagen von LRS-betroffenen Kindern selbst basieren, ein Unterrichtsmodell zu entwickeln und zu erproben. Die Arbeit lässt sich in das Forschungsfeld Schüler mit Lernschwierigkeiten im Fach Englisch in der Grundschule einordnen. Die empirischen Untersuchungen wurden in den Jahren 2009 bis 2011 durchgeführt.
Der theoretische Abschnitt befasst sich mit neurophysiologischen und entwicklungspsychologischen Aspekten des Spracherwerbs, Erörterungen zum Lesen- und Schreibenlernen sowie den Schwierigkeiten, die für legasthene Kinder beim Fremdspracherwerb entstehen. Im nächsten Schritt wird die Intervention und Förderung behandelt, wobei auf alternative Förderkonzepte besonderes Augenmerk gerichtet wird.
Der Fokus der empirischen Untersuchung liegt auf LRS im Englischunterricht. Die Erhebungen wurden im Rahmen des regulären Englischunterrichts in einer dritten Klasse durchgeführt. Es handelte sich um eine reine LRS-Klasse, daher wird das Thema „Inklusion“ in vorliegender Studie nicht explizit behandelt. Im Vordergrund stehen vielmehr die Ideen und Gedanken der legasthenen Lernenden zu ihrem Unterricht und zu Möglichkeiten der Überwindung ihrer besonderen Schwierigkeiten im Fach Englisch.
Die Gedanken und Ansichten der Lernenden auf Basis der theoretischen Erkenntnisse aus Neurowissenschaften und Fachdidaktik, z. B. zum Umfang des Lernstoffes, zu Lernpausen und Entspannung, sind die Basis für ein ganzheitliches Unterrichtskonzept. Ein solches Konzept wurde für die legasthenen Schüler der Fokusgruppe erarbeitet sowie im Rahmen einer fünf Unterrichtsstunden umfassenden Lektion erprobt und evaluiert. Mit der vorliegenden Studie wird ein Konzept vorgeschlagen, das die Grundlagen für erfolgreiches Fremdsprachenlernen schafft, nämlich Freude und Motivation. Mit der Integration von LRS-gerechten Lernmethoden und -umgebungen leistet das Konzept einen Beitrag dazu, Schüler entsprechend ihren Fähigkeiten im Fach Englisch in der Grundschule zu fördern und fordern.The present doctorial dissertation has the intention to find out how very young dyslexic children learn the English language. At a very early stage of learning a second language the author wants to find out what ideas children have about learning English. Their thoughts will be entered in a comprehensive teaching concept which will be tested in the classroom.
The thesis can be classified in the field of teaching children with learning difficulties in the elementary school. The empirical research was made between 2009 and 2011.
The theoretical part includes neurophysiological and developmental psychological aspects of language acquisition. It discusses the way children learn how to read and write and the difficulties dyslexic pupils might have when learning a foreign language. After that the author points out the common facilities of helping those children whereas alternative methods play an important role.
Dyslexia in the English classroom is the focal point of the empirical part of the thesis. The evaluation was made in class three of a German elementary school. The evaluated class was a special class where only dyslexic children were being taught. As inclusion is not the crucial point the main emphasis is on the pupils’ ideas of how to learn a second language although having difficulties in learning to write and read in the mother tongue. As well as their opinions and the latest neurophysiological findings, for instance the complexity of learning matters, learning breaks and compensation are the basis of the comprehensive teaching concept. The concept was developed and experienced in the classroom. The survey was tested within five lessons of an English language unit.
The present concept covers the basics of successful second language learning, namely motivation and enjoyment. The concept includes dyslexia friendly learning methods which enables young pupils to learn English according their strength and abilities
Temperature-independent almost perfect photon entanglement from quantum dots via the SUPER scheme
No full textEntangled photon pairs are essential for quantum communication technology. They can be generated on-demand by semiconductor quantum dots, but several mechanisms are known to reduce the degree of entanglement. While some obstacles like the finite fine-structure splitting of the exciton states can currently be overcome, the excitation scheme itself can impair the entanglement fidelity. Here, we demonstrate that the swing-up of quantum emitter population (SUPER) scheme, using two red-detuned laser pulses applied to a quantum dot in a cavity, yields almost perfectly entangled photons. The entanglement remains robust against phonon influences even at elevated temperatures, due to decoupling of the excitation and emission process. With this achievement, quantum dots are ready to be used as entangled photon pair sources in applications requiring high degrees of entanglement up to temperatures of approximately 80 K
Supplementary document for Temperature-independent almost perfect photon entanglement from quantum dots via the SUPER scheme - 6744409.pdf
No full textSupplemental Information including the Hamiltonian and further discussio
Different Types of Photon Entanglement from a Constantly Driven Quantum Emitter Inside a Cavity
No full textBell states are the most prominent maximally entangled photon states. In a typical four-level emitter, like a semiconductor quantum dot, the photon states exhibit only one type of Bell state entanglement. By adding an external driving to the emitter system, also other types of Bell state entanglement are reachable without changing the polarization basis. In this work, it is shown under which conditions the different types of entanglement occur and analytical equations are given to explain these findings. Furthermore, special points are identified, where the concurrence, being a measure for the degree of entanglement, drops to zero, while the coherences between the two-photon states stay strong. Results of this work pave the way to achieve a controlled manipulation of the entanglement type in practical devices.</p
Swing-Up of Quantum Emitter Population Using Detuned Pulses
No full textThe controlled preparation of the excited state in a quantum emitter is a prerequisite for its usage as a single-photon source - a key building block for quantum technologies. In this paper, we propose a coherent excitation scheme using off-resonant pulses. In the usual Rabi scheme, these pulses would not lead to a significant occupation. This is overcome by using a frequency-modulated pulse to swing up the excited-state population. The same effect can be obtained using two pulses with different strong detunings of the same sign. We theoretically analyze the applicability of the scheme to a semiconductor quantum dot. In this case, the excitation is several millielectronvolts below the band gap, i.e., far away from the detection frequency, allowing for easy spectral filtering, and does not rely on any auxiliary particles such as phonons. Our scheme has the potential to lead to the generation of close-to-ideal photons. </p
Schrödinger cat states in quantum-dot-cavity systems
No full textA Schrödinger-cat state is a coherent superposition of macroscopically distinguishable quantum states, in quantum optics usually realized as superposition of coherent states. Protocols to prepare photonic cats have been presented for atomic systems. Here we investigate in what manner and how well the preparation protocols can be transferred to a solid-state platform, namely, a semiconductor quantum-dot-cavity system. In quantum-dot-cavity systems there are many disruptive influences like cavity losses, the radiative decay of the quantum dot, and the coupling to longitudinal acoustic phonons. We show that for one of the protocols these influences kill the quantum coherence between the states forming the cat, while for a second protocol a parameter regime can be identified where the essential characteristics of Schrödinger-cat states survive the environmental influences under conditions that can be realized with current equipment.</p
Report of the IAU/IAG Working Group on cartographic coordinates and rotational elements: 2006
No full textEvery three years the IAU/IAG Working Group on Cartographic Coordinates and Rotational Elements revises tables giving the directions of the poles of rotation and the prime meridians of the planets, satellites, minor planets, and comets. This report introduces improved values for the pole and rotation rate of Pluto, Charon, and Phoebe, the pole of Jupiter, the sizes and shapes of Saturn satellites and Charon, and the poles, rotation rates, and sizes of some minor planets and comets. A high precision realization for the pole and rotation rate of the Moon is provided. The expression for the Sun’s rotation has been changed to be consistent with the planets and to account for light travel tim
Enhancing quantum cryptography with quantum dot single-photon sources
No full textQuantum cryptography harnesses quantum light, in particular single photons,
to provide security guarantees that cannot be reached by classical means. For
each cryptographic task, the security feature of interest is directly related
to the photons' non-classical properties. Quantum dot-based single-photon
sources are remarkable candidates, as they can in principle emit
deterministically, with high brightness and low multiphoton contribution. Here,
we show that these sources provide additional security benefits, thanks to the
tunability of coherence in the emitted photon-number states. We identify the
optimal optical pumping scheme for the main quantum-cryptographic primitives,
and benchmark their performance with respect to Poisson-distributed sources
such as attenuated laser states and down-conversion sources. In particular, we
elaborate on the advantage of using phonon-assisted and two-photon excitation
rather than resonant excitation for quantum key distribution and other
primitives. The presented results will guide future developments in solid-state
and quantum information science for photon sources that are tailored to quantum
communication tasks
