Quantum control of electromagnetically induced transparency dispersion via atomic tunneling in a double-well Bose-Einstein condensate

Electromagnetically induced transparency (EIT) is an important tool for controlling light propagation and nonlinear wave mixing in atomic gases with potential applications ranging from quantum computing to table top tests of general relativity. Here we consider EIT in an atomic Bose-Einstein condensate (BEC) trapped in a double-well potential. A weak probe laser propagates through one of the wells and interacts with atoms in a three-level Lambda configuration. The well through which the probe propagates is dressed by a strong control laser with Rabi frequency Omega(mu), as in standard EIT systems. Tunneling between the wells at the frequency g provides a coherent coupling between identical electronic states in the two wells, which leads to the formation of interwell dressed states. The macroscopic interwell coherence of the BEC wave function results in the formation of two ultranarrow absorption resonances for the probe field that are inside of the ordinary EIT transparency window. We show that these new resonances can be interpreted in terms of the interwell dressed states and the formation of a type of dark state involving the control laser and the interwell tunneling. To either side of these ultranarrow resonances there is normal dispersion with very large slope controlled by g. We discuss prospects for observing these ultranarrow resonances and the corresponding regions of high dispersion experimentally.

Exploring critical literacy in Swedish education : Introductory notes

This article is an introductory note to The thematic section in this issue of Education Inquiry has its background in the need for research interpreting literacy from a critical perspective. Teaching literacy is not solely about technical reading skills but is also about understanding and the making of meaning. From that point of view, teaching must also consider the use of language, the context within which language is used, and issues of power. The thematic section includes five articles about critical literacy in Swedish education. The contributions were developed after a workshop conducted by Professor Hilary Janks, University of the Witwatersrand, Johannesburg. She introduces the framework of a critical literacy theory in the first article of the issue. Further, the contributions of Swedish scholars are united in their interest in applying a mode of critical literacy designed by Janks to different practices, sites and speech-events, for example policy documents, home reading, teaching and learning practices. The articles offer a wide perspective of critical literacy in education and further understanding of the complex processes in teaching.