Transmission Resonance in an Infinite Strip of Phason-Defects of a Penrose Approximant Network

An exact method that analytically provides transfer matrices in finite networks of quasicrystalline approximants of any dimensionality is discussed. We use these matrices in two ways: a) to exactly determine the band structure of an infinite approximant network in analytical form; b) to determine, also analytically, the quantum resistance of a finite strip of a network under appropriate boundary conditions. As a result of a subtle interplay between topology and phase interferences, we find that a strip of phason-defects along a special symmetry direction of a low 2-d Penrose approximant, leads to the rigorous vanishing of the reflection coefficient for certain energies. A similar behavior appears in a low 3-d approximant. This type of ``resonance" is discussed in connection with the gap structure of the corresponding ordered (undefected) system.Comment: 18 pages special macros jnl.tex,reforder.tex, eqnorder.te

On the de Haas-van Alphen effect in inhomogeneous alloys

We show that Landau level broadening in alloys occurs naturally as a consequence of random variations in the local quasiparticle density, without the need to consider a relaxation time. This approach predicts Lorentzian-broadened Landau levels similar to those derived by Dingle using the relaxation-time approximation. However, rather than being determined by a finite relaxation time $\tau$, the Landau-level widths instead depend directly on the rate at which the de Haas-van Alphen frequency changes with alloy composition. The results are in good agreement with recent data from three very different alloy systems.Comment: 5 pages, no figure

Simulating Quantum Dynamics with Entanglement Mean Field Theory

Exactly solvable many-body systems are few and far between, and the utility of approximate methods cannot be overestimated. Entanglement mean field theory is an approximate method to handle such systems. While mean field theories reduce the many-body system to an effective single-body one, entanglement mean field theory reduces it to a two-body system. And in contrast to mean field theories where the self-consistency equations are in terms of single-site physical parameters, those in entanglement mean field theory are in terms of both single- and two-site parameters. Hitherto, the theory has been applied to predict properties of the static states, like ground and thermal states, of many-body systems. Here we give a method to employ it to predict properties of time-evolved states. The predictions are then compared with known results of paradigmatic spin Hamiltonians.Comment: 8 pages, 3 figure

"Allowing it to speak out of him": The Heterobiographies of David Malouf, Antonio Tabucchi and Marguerite Yourcenar

Under true pretences We know very little about the life of Ovid, and it is this absence of fact that has made him useful as the central figure of my narrative and allowed me the liberty of free invention, since what I wanted to write was neither historical novel nor biography, but a fiction with its roots in possible event. Thus starts the Afterword of David Malouf’s An Imaginary Life, a novel in which the poet Ovid, exiled from Rome, narrates his experience in the border outpost of Tomis, near the delta of the Danube on the Black Sea. ‘Relegated’ among the Getae at the edges of the Empire and ‘expelled form the confines of [the] Latin tongue’ (IL 26), this glittering and cynical poet undergoes a series of changes or metamorphoses. Initially pining for Rome and its sophisticated, complex language, he learns to overcome his hostility towards the barbarous people and their language, but when he discovers a wild Child that had been raised by the wolves in the forest and captures him with the intention of teaching him to speak and to be human, he soon realises that he himself has to learn from the Child another language, based not on symbolization and arbitrary convention but on an intuitive identity with things, on becoming the things signified in silence. After the death of the village’s elderly chief, which the villagers blame on the child’s demonic powers, the poet and the Child escape north across the frozen river. Ovid’s death is the poet’s final transformation, perhaps a literal metamorphosis like the ones described in Ovid’s great poem. Malouf’s Afterword concludes: My purpose was to make this glib fabulist of ‘the changes’ live out in reality what had been, in his previous existence, merely the occasion for dazzling literary display. (IL 154) Is Malouf’s novel then a fantasy inspired by ‘mere’ literary dazzle or, as ‘a fiction with its roots in possible event’, is it a work that, while not claiming to the factual accuracy of biography or the broad reliability of the historical background of a historical novel, can however still claim to be rooted in verisimilitude, in events that, although not documented, are nevertheless possible, as would be the case with a realist novel, or in Aristotelian poetics? The Afterword thematizes a tension between the desire to anchor the novel to history and the desire to free Ovid from historical necessity. How can Ovid live out ‘in reality’ the metamorphoses to which he is subjected, if metamorphoses are but the occasion for ‘literary display’? This tension also defines, more widely, the large number of novels written as if they were the autobiographies of historical personages, novels that gesture towards historical factuality and literary fictionality, towards ‘truth’ and invention, and exist under the sign of an essential structural displacement (the ‘autobiography’ is written by another) that brings to the foreground structural, narrative, and ethical issues also central to autobiography itself. (First paragraphs of submitted version