Two-dimensional Bloch electrons in perpendicular magnetic fields: an exact calculation of the Hofstadter butterfly spectrum

The problem of two-dimensional, independent electrons subject to a periodic potential and a uniform perpendicular magnetic field unveils surprisingly rich physics, as epitomized by the fractal energy spectrum known as Hofstadter's Butterfly. It has hitherto been addressed using various approximations rooted in either the strong potential or the strong field limiting cases. Here we report calculations of the full spectrum of the single-particle Schr\"{o}dinger equation without further approximations. Our method is exact, up to numerical precision, for any combination of potential and uniform field strength. We first study a situation that corresponds to the strong potential limit, and compare the exact results to the predictions of a Hofstadter-like model. We then go on to analyze the evolution of the fractal spectrum from a Landau-like nearly-free electron system to the Hofstadter tight-binding limit by tuning the amplitude of the modulation potential

Implementation Essays on Decision Support Systems

The "Task Force Meeting on Decision Support Systems (DSS)" held at IIASA in June 1980 has stimulated some new thinking in this area of research in the MMT group (Management and Technology Research Area). The discussion pointed out the important role that DSS can play in assisting decision makers. DSS should be seen as a complicated socio-technical system for solving relevant problems in the wider social context. This paper is oriented towards technical aspects of DSS, but human factors have been taken into account as well. It contains some points of view of implementation; it reviews some basic functions which are to be performed by DSS and techniques which can simplify DSS design. A possible implementation structure based on computer network theory is presented, and in addition, some of the problems involved are discussed The author Jan Janecek participated in the IIASA Young Scientists Summer Program 1980. He was attached to the MMT Research Area for three months. This report is one of the results of his work during that period

Andrey Bely: A Critical Review

Andrey Bely, novelist, essayist, theoretician, critic, and poet, was a central figure in the Russian Symbolist movement of the 1920s, the most important literary movement in Russia in this century. Bely articulated a Symbolist aesthetic and originated a new approach to the study of Russian metrics and versification, giving rise to a new scholarly discipline that still thrives in the West. Although regarded by some critics, including Vladimir Nabokov, as the author of the greatest Russian novel of this century, Bely has been nearly forgotten in his native country for ideological reasons. In the West he remains little known and generally under-valued. But with recent English translations of Kotik Letaev and his masterpiece, Petersburg, interest in Bely is increasing. Janecek\u27s book brings together some of the best modern scholarship on Bely and the Russian Symbolist movement of the 1920s. Gerald Janecek is associate professor of Russian at the University of Kentucky.https://uknowledge.uky.edu/upk_slavic_languages_and_societies/1001/thumbnail.jp

Undiagnosing Iphis: How the Lack of Trauma in John Gower’s “Iphis And Iante” Reinforces a Subversive Trans Narrative

Trauma has long played a role in queer narratives, including Ovid’s “Iphis and Ianthe”, which many scholars have interpreted as reinforcing heteronormativity through Iphis’s transformation into a man in order to marry Ianthe. However, I argue that John Gower’s rendition of this tale reframes Iphis as a trans man and allows us to understand the poem as a subversive trans narrative that revolts against cisnormative conceptions of gender. Utilizing Judith Butler’s writing on the medicalization of gender, I explore the relationship between trauma, performance, and gender within the Ovidian and Gowerian versions of Iphis