350 research outputs found
Topological Insulators 101
No full textWe thought we knew all there was to know about band insulators back in the 1930s. However, in the last 10 years we have learnt that there distinct types of band insulators in 2 and 3 dimensions. The distinction between these types is topological , a term Dr. Ganpathy Murthy will explain. He will introduce the idea of band topology in detail in 2D. He will then use the example of the integer quantum Hall effects to show that a topological insulator has edge states that are robust to disorder. Next he will introduce time-reversal invariance, which puts powerful constraints on band insulators. Once again, edge modes will prove to be extremely useful in characterizing the different types of band insulators. He will end up by talking about 3D topological insulators and some of the phenomenology associated with them
Notules sur Emptiness: A Double Comic Strip de Bharath Murthy
No full textÀ travers ces 12 notules je cherche à montrer comment l’auteur Bharath Murthy a su développer une BD « scientifique » ici plus concrètement philosophique sur le la présence-absence d’une essence appelée « âme » (ou « moi », « soi », « dieu », etc.) dans la tradition occidentale et réaffirmée jusque dans l’IA par certains, et déconstruite par l’« emptiness » aporétique bouddhique en utilisant les techniques spécifiques de la bande dessinée procurées par le texte et l’image (du bleed à la graphiation).Through these 12 “footnotes” I try to show how the author Bharath Murthy has been able to develop a "scientific" comic strip, here more concretely a philosophical one, on the presence-absence of an essence called "soul" (or "self", "self", "god", etc.) in the Western tradition and reaffirmed in AI by some, and deconstructed by the Buddhist aporetic "emptiness", using the specific techniques of comics provided by the text and the image (from bleed to graphiation)
Disordered SU(<i>N</i>) antiferromagnets and the renormalization of charged instanton gases in three dimensions
No full textBig Bang Theory, Dark Matter and Dark Energy: 2. What’s the Evidence for the Big Bang and Expansion of the Universe? What Do We Measure and How?
No full textWhat’s the evidence? How we know the Big Bang happened, and that the universe is expanding and accelerating. How we measure how fast different parts of the Universe are moving away
Big Bang Theory, Dark Matter and Dark Energy: 1. The Big Picture; the History of the Universe from the Big Bang to Now
No full textThe big picture; the history of the universe from the Big Bang to now. Important scientific milestones leading to our present knowledge
Hall Crystal States at<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="italic">ν</mml:mi><mml:mspace /><mml:mo>=</mml:mo><mml:mspace /><mml:mn>2</mml:mn><mml:mn /></mml:math>and Moderate Landau Level Mixing
No full textBig Bang Theory, Dark Matter and Dark Energy: 3. More Evidence, Including the Evidence for Dark Matter, and Dark Energy
No full textMore on the Big Bang, how we measure how far away different parts of the universe are Dark Matter, Dark Energ
Quantum Hall to Insulator Transition in the Bilayer Quantum Hall Ferromagnet
No full textWe describe a phase transition of the bilayer quantum Hall ferromagnet at . In the presence of static disorder (modeled by a periodic potential), bosonic spinons undergo a superfluid-insulator transition while preserving ferromagnetism. The Mott insulating phase has an emergent photon, and the transition is between Higgs and Coulomb phases of this photon. Consequences for charge and counterflow conductivity and for interlayer tunneling conductance are discussed.PhysicsAuthor's Origina
Dynamic rheology of capsule suspension: the role of unsteady capsule dynamics and multiparticle interaction
No full textThree-dimensional numerical simulations using immersed-boundary methods are performed to study the rheology of capsule suspensions. Two well-known dynamics of the capsules are the tank-treading and tumbling motions. The motivation of the thesis is twofold: first, to study the micro-macro link between the individual cell dynamics and the rheology of the cell suspension under a dilute condition, and, second, to extend the analysis to a dense suspension in which the multi-body interaction also contributes to the suspension rheology. A recent theoretical study in the limit of small deformation, supported by experimental work, suggested that the effective viscosity of a vesicle suspension in dilute limit exhibits a singularity in the form of a viscosity minimum at the threshold of the transition between the tank-treading and the tumbling motion. In the first part of the thesis, we extend this study to the dilute suspension of capsules undergoing large deformation. The objective here is to relate the time- dependent rheology with the time-dependent capsule dynamics, and study the role of the tank-treading-to- tumbling transition. We find that the time-averaged rheology obtained for the non-spherical capsules undergoing the unsteady motion is qualitatively similar to that obtained for the spherical capsules undergoing the steady tank-treading motion, and that the tank-treading-to-tumbling transition has only a marginal effect. The time-averaged rheology exhibits a shear viscosity minimum when the capsules are in a swinging motion at high shear rates but not at low shear rates unlike that of a vesicle suspension which exhibits a shear viscosity minimum at the point of transition. In the second part, we extend our study to dense suspension of initially spherical capsules. We find that the shear viscosity minimum gradually diminishes with increasing capsule volume fraction. We explain this result by decomposing the particle shear stress into elastic and viscous components. The elastic component is observed to increase but the viscous component remains constant with respect to increasing volume fraction. It is also shown that the elastic contribution is shear-thinning, but the viscous contribution is shear-thickening. The deformation and orientation dynamics of the capsules in dense suspension are also presented. Non-trivial results for the normal stress differences and particle pressure are also analysed.Ph. D.Includes bibliographical referencesIncludes vitaby Ram Chandra Murthy Kallur
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