Use of quantum quenches to probe the equilibrium current patterns of ultracold atoms in an optical lattice

Atomic bosons and fermions in an optical lattice can realize a variety of interesting condensed matter states that support equilibrium current patterns in the presence of synthetic magnetic fields or non-abelian gauge fields. As a route to probing such mass currents, we propose a nonequilibrium quantum quench of the Hamiltonian that dynamically converts the current patterns into experimentally measurable real-space density patterns. We illustrate how a specific such "unidirectional" quench of the optical lattice can be used to uncover checkerboard and stripe current orders in lattice Bose superfluids and Fermi gases, as well as chiral edge currents in an integer quantum Hall state.Comment: 5 pages, 4 figures, Slightly revised, to appear in Phys. Rev. A (Rapid Communication

Productivity growth in Norwegian ferry links 1988-1996, and implications for regulation

Tese de Mestrado em História Moderna apresentada à Faculdade de Letras da Universidade de CoimbraA presente dissertação aborda o domínio senhorial em Cantanhede nos finais do Antigo Regime, protagonizado pela Casa Cantanhede-Marialva. Procuramos numa primeira fase analisar o domínio senhorial numa vertente jurisdicional e territorial e encetamos, em seguida, uma abordagem à formação da Casa senhorial de Cantanhede-Marialva apresentando os privilégios e direitos jurisdicionais que deteve ao longo da sua existência. Prosseguimos com a análise dos territórios do Concelho de Cantanhede onde o donatário detinha domínio. Destacamos a Coutada como território de reserva de recursos naturais que suscitou problemas com a população gerando alguns processos. Por fim, encetamos uma viagem pela contestação antisenhorial que se verificou no Antigo Regime português, terminando com a análise da situação cantanhedense. Com o estudo deste tema, procuramos contribuir para um maior conhecimento sobre o domínio senhorial da Época Moderna e, de forma particular, sobre contestação antisenhorial em vigor nos finais do Antigo Regime. A Carta enviada pela Câmara Municipal de Cantanhede às Cortes Constituintes em 1821 constitui-se como um documento singular neste contexto

Erfaringer fra veien ut og inn i fellesskapene. En kvalitativ studie om hva som bidrar til deltakelse i fritidsaktivitet blant mennesker med psykiske lidelser.

Background: Mental health problems often lead to isolation and reduced participation in leisure activity. Leisure activity in group has the potential to promote social contact and coping. There has been little research on what is needed to enable people with mental illness to participate in leisure group activities. Purpose: The aim of the project was to find out what can promote participation in leisure group activities among people with mental illnesses. Method: Using qualitative design, five individuals were strategically selected for a semistructured interview. The interviews were analyzed by systematic text condensation. Results: The results show that external factors such as motivation from other helpers, motivated leaders and secure activities can contribute to participation. Furthermore, it appears that personal characteristics are about to receive and accept support from others. It also seems beneficial to have previous experience with the activity and a sense of coping. The most surprising finding is that participation in leisure activity seems to be linked to a larger existential choice in finding meaning in life. Conclusion: The findings show that participation in activity is a complex phenomenon, and is of great importance for people with mental illnesses. The finding that the existential dimension seems to play some role, underscore that locally based services need to take this dimension into account. There is a need for further research to help the development of leisure activities in order to match the user’s need. Further research will also contribute to a necessary awareness of the leisure activities’ extensive potential to increase coping in everyday lif

Cavity-Dumping in solitär modengekoppelten Femtosekunden-Laseroszillatoren

Das Thema dieser Dissertation ist die Erforschung und Anwendung kompakter Femtosekunden-Laseroszillatoren mit Cavity-Dumping. Diese sind von großer Relevanz, da sie, wie erstmalig demonstriert wird, eine Alternative für wesentlich komplexere Verstärkersysteme im Mikrojoule-Energiebereich sind. Darüber hinaus werden erstmals die Besonderheiten der vielschichtigen Dynamik in modengekoppelten Lasern mit Cavity-Dumping im Detail analysiert. Es werden aus den tieferen Erkenntnissen zur Pulsformungsdynamik Designkriterien für die Realisierung der Laser abgeleitet. Die theoretischen Vorhersagen decken sich in außerordentlich guter Weise mit dem tatsächlichen Verhalten der experimentell aufgebauten Systeme. Diese basieren auf dem direkt diodengepumpten Lasermaterial Ytterbium, wobei es durch Ausnutzung der theoretischen Erkenntnisse erstmalig gelingt, Femtosekunden-Pulse im Mikrojoule-Bereich bei Wiederholraten von einem Megahertz zu erzeugen. Dies sind bislang die höchsten Pulsenergien, die mittels Femtosekunden-Oszillatoren mit Cavity-Dumping erreicht werden. Das eindrucksvolle Potenzial des Konzepts wird anhand von Anwendungen aus der nichtlinearen Optik, der Biomedizin und der Mikrostrukturierung demonstriert. Die erforschten Lichtquellen ebnen den Weg für eine breite Anwendung von Femtosekunden-Pulsen mit relativ hoher Energie in vielen Bereichen von Wissenschaft und Technik

Graphene: Kinks, Superlattices, Landau levels, and Magnetotransport

We review recent work on superlattices in monolayer and bilayer graphene. We highlight the role of the quasiparticle chirality in generating new Dirac fermion modes with tunable anisotropic velocities in one dimensional (1D) superlattices in both monolayer and bilayer graphene. We discuss the structure of the Landau levels and magnetotransport in such superlattices over a wide range of perpendicular (orbital) magnetic fields. In monolayer graphene, we show that an orbital magnetic field can reverse the anisotropy of the transport imposed by the superlattice potential, suggesting possible switching-type device applications. We also consider topological modes localized at a kink in an electric field applied perpendicular to bilayer graphene, and show how interactions convert these modes into a two-band Luttinger liquid with tunable Luttinger parameters. The band structures of electric field superlattices in bilayer graphene (with or without a magnetic field) are shown to arise naturally from a coupled array of such topological modes. We briefly review some bandstructure results for 2D superlattices. We conclude with a discussion of recent tunneling and transport experiments and point out open issues.Comment: Invited Review Article for Special Issue on Graphene, References added, Typos correcte

Lipid peroxidation and chlorophyll fluorescence of photosystem ii performance during drought and heat stress is associated with the antioxidant capacities of C3 sunflower and C4 maize varieties

Agricultural production is predicted to be adversely affected by an increase in drought and heatwaves. Drought and heat damage cellular membranes, such as the thylakoid membranes where photosystem II occurs (PSII). We investigated the chlorophyll fluorescence (ChlF) of PSII, photosynthetic pigments, membrane damage, and the activity of protective antioxidants in drought-tolerant and -sensitive varieties of C3 sunflower and C4 maize grown at 20/25 and 30/35 °C. Drought-tolerant varieties retained PSII electron transport at lower levels of water availability at both temperatures. Drought and heat stress, in combination and isolation, had a more pronounced effect on the ChlF of the C3 species. For phenotyping, the maximum fluorescence was the most effective ChlF measure in characterizing varietal variation in the response of both species to drought and heat. The drought-tolerant sunflower and maize showed lower lipid peroxidation under drought and heat stress. The greater retention of PSII function in the drought-tolerant sunflower and maize at higher temperatures was associated with an increase in the activities of antioxidants (glutathione reductase, superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase), whereas antioxidant activity declined in the drought-sensitive varieties. Antioxidant activity should play a key role in the development of drought- and heat-tolerant crops for future food security