High efficiency switching using graphene based electron 'optics'

The absence of a band-gap in graphene limits the gate modulation of its electron conductivity, both in regular graphene as well as in PN junctions, where electrostatic barriers prove transparent to Klein tunneling. We demonstrate a novel way to directly open a gate-tunable transmission gap across graphene PN junctions (GPNJ) by introducing an additional barrier in the middle that replaces Klein tunneling with regular tunneling, allowing us to electrostatically modulate the current by several orders of magnitude. The gap arises by angularly sorting electrons by their longitudinal energy and filtering out the hottest, normally incident electrons with the tunnel barrier, and the rest through total internal reflection. Using analytical and atomistic numerical studies of quantum transport, we show that the complete filtering of all incident electrons causes the GPNJ to act as a novel metamaterial with a unique gate-tunable transmission-gap that generates a sharp non-thermal switching of electrons. In fact, the transmission gap gradually diminishes to zero as we electrostatically reduce the voltage gradient across the junction towards the homogeneous doping limit. The resulting gate tunable metal-insulator transition enables the electrons to overcome the classic room temperature switching limit of kTln10/q = 60mV/decade for subthreshold conduction

Variations on the Misogynistic Nature of 'The Seven Sages' in Different Arabic Manuscript Copies (17th - 18th Centuries)

Variants of ‘The Malice of Women and the Malice of Men’, known under the title of ‘The Seven Sages’, have circulated since the 9th century throughout the world and have been susceptible to various kinds of influence, be they religious, linguistic, or thematic. Moreover, the text functioned as a ‘mirror for princes’ and was entertaining for many readers, who were predominantly men. Comparing the existing Arabic manuscripts – Sprenger 1368 (Staatsbibliothek zu Berlin), Glaser 166 (Staatsbibliothek zu Berlin), and Paris arabe 3639 (Bibliothèque nationale de France) – this article aims to show variance among the Arabic versions of ‘The Seven Viziers’ and their implications for the theme of misogyny that runs through the book. The variance, this article argues, is one of degree and not kind. Special attention is given to certain structural (story corpus), linguistic, and thematic elements (associations to the story of Potiphar and his wife in the Qurʾān), all of which have implications for the theme of misogyny. Finally, the article looks into the reception of the text, especially by general readers, who used it to confirm their negative perception of women

How Imbalanced Excitation and Inhibition May Cause Low Entropy Brain Dynamics

To study the effect of the imbalance of excitation and inhibition neurons on brain entropy using a computer model of a brain. The brain model will be composed of a neural network and entropy of the neural network will be measured quantitatively. Entropy in this context quantifies how many different patterns of activated neurons the brain can create. Imbalance between excitation and inhibition neurons causes the brain to malfunction, which can be an underlying cause of autism