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A Topological Framework for Local Structure Analysis in Condensed Matter

Lazar, Emanuel A.; Han, Jian; Srolovitz, David J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/08/2015
Relevância na Pesquisa
65.57%
Physical systems are frequently modeled as sets of points in space, each representing the position of an atom, molecule, or mesoscale particle. As many properties of such systems depend on the underlying ordering of their constituent particles, understanding that structure is a primary objective of condensed matter research. Although perfect crystals are fully described by a set of translation and basis vectors, real-world materials are never perfect, as thermal vibrations and defects introduce significant deviation from ideal order. Meanwhile, liquids and glasses present yet more complexity. A complete understanding of structure thus remains a central, open problem. Here we propose a unified mathematical framework, based on the topology of the Voronoi cell of a particle, for classifying local structure in ordered and disordered systems that is powerful and practical. We explain the underlying reason why this topological description of local structure is better suited for structural analysis than continuous descriptions. We demonstrate the connection of this approach to the behavior of physical systems and explore how crystalline structure is compromised at elevated temperatures. We also illustrate potential applications to identifying defects in plastically deformed polycrystals at high temperatures...

Dynamics of Symmetry Breaking Out of Equilibrium: From Condensed Matter to QCD and the Early Universe

Boyanovsky, D.; de Vega, H. J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 14/09/1999
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The dynamics of symmetry breaking during out of equilibrium phase transitions is a topic of great importance in many disciplines, from condensed matter to particle physics and early Universe cosmology with definite experimental impact. In these notes we provide a summary of the relevant aspects of the dynamics of symmetry breaking in many different fields with emphasis on the experimental realizations. In condensed matter we address the dynamics of phase ordering, the emergence of condensates, coarsening and dynamical scaling. In QCD the possibility of disoriented chiral condensates of pions emerging during a strongly out of equilibrium phase transition is discussed. We elaborate on the dynamics of phase ordering in phase transitions in the Early Universe, in particular the emergence of condensates and scaling in FRW cosmologies. We mention some experimental efforts in different fields that study this wide ranging phenomena and offer a quantitative theoretical description both at the phenomenological level in condensed matter, introducing the scaling hypothesis as well as at a microscopic level in quantum field theories. The emergence of semiclassical condensates and a dynamical length scale is shown in detail, in quantum field theory this length scale is constrained by causality. The large N limit provides a natural bridge to compare the solutions in different settings and to establish similarities and differences.; Comment: 35 pages...

Quantum phase transition for the BEC--BCS crossover in condensed matter physics and CPT violation in elementary particle physics

Klinkhamer, F. R.; Volovik, G. E.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
65.61%
We discuss the quantum phase transition that separates a vacuum state with fully-gapped fermion spectrum from a vacuum state with topologically-protected Fermi points (gap nodes). In the context of condensed-matter physics, such a quantum phase transition with Fermi point splitting may occur for a system of ultracold fermionic atoms in the region of the BEC-BCS crossover, provided Cooper pairing occurs in the non-s-wave channel. For elementary particle physics, the splitting of Fermi points may lead to CPT violation, neutrino oscillations, and other phenomena.; Comment: 13 pages, 1 figure, v3: published version

Zoology of condensed matter: Framids, ordinary stuff, extra-ordinary stuff

Nicolis, Alberto; Penco, Riccardo; Piazza, Federico; Rattazzi, Riccardo
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 15/01/2015
Relevância na Pesquisa
65.57%
We classify condensed matter systems in terms of the spacetime symmetries they spontaneously break. In particular, we characterize condensed matter itself as any state in a Poincar\'e-invariant theory that spontaneously breaks Lorentz boosts while preserving at large distances some form of spatial translations, time-translations, and possibly spatial rotations. Surprisingly, the simplest, most minimal system achieving this symmetry breaking pattern---the "framid"---does not seem to be realized in Nature. Instead, Nature usually adopts a more cumbersome strategy: that of introducing internal translational symmetries---and possibly rotational ones---and of spontaneously breaking them along with their space-time counterparts, while preserving unbroken diagonal subgroups. This symmetry breaking pattern describes the infrared dynamics of ordinary solids, fluids, superfluids, and---if they exist---supersolids. A third, "extra-ordinary", possibility involves replacing these internal symmetries with other symmetries that do not commute with the Poincar\'e group, for instance the galileon symmetry, supersymmetry or gauge symmetries. Among these options, we pick the systems based on the galileon symmetry, the "galileids", for a more detailed study. Despite some similarity...

Ultracold atomic gases in optical lattices: mimicking condensed matter physics and beyond

Lewenstein, Maciej; Sanpera, Anna; Ahufinger, Veronica; Damski, Bogdan; De, Aditi Sen; Sen, Ujjwal
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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We review recent developments in the physics of ultracold atomic and molecular gases in optical lattices. Such systems are nearly perfect realisations of various kinds of Hubbard models, and as such may very well serve to mimic condensed matter phenomena. We show how these systems may be employed as quantum simulators to answer some challenging open questions of condensed matter, and even high energy physics. After a short presentation of the models and the methods of treatment of such systems, we discuss in detail, which challenges of condensed matter physics can be addressed with (i) disordered ultracold lattice gases, (ii) frustrated ultracold gases, (iii) spinor lattice gases, (iv) lattice gases in "artificial" magnetic fields, and, last but not least, (v) quantum information processing in lattice gases. For completeness, also some recent progress related to the above topics with trapped cold gases will be discussed.; Comment: Review article. v2: published version, 135 pages, 34 figures

The Onset of Phase Transitions in Condensed Matter and Relativistic QFT

Rivers, R. J.; Kavoussanaki, E.; Karra, G.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 19/01/2000
Relevância na Pesquisa
65.59%
Kibble and Zurek have provided a unifying causal picture for the appearance of topological defects like cosmic strings or vortices at the onset of phase transitions in relativistic QFT and condensed matter systems respectively. There is no direct experimental evidence in QFT, but in condensed matter the predictions are largely, but not wholly, supported in superfluid experiments on liquid helium. We provide an alternative picture for the initial appearance of strings/vortices that is commensurate with all the experimental evidence from condensed matter and consider some of its implications for QFT.; Comment: 37 pages, to be published in Condensed Matter Physics, 2000

Exploiting Grids for applications in Condensed Matter Physics

Pujari, Bhalchandra S.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 11/02/2010
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65.57%
Grids - the collection of heterogeneous computers spread across the globe - present a new paradigm for the large scale problems in variety of fields. We discuss two representative cases in the area of condensed matter physics outlining the widespread applications of the Grids. Both the problems involve calculations based on commonly used Density Functional Theory and hence can be considered to be of general interest. We demonstrate the suitability of Grids for the problems discussed and provide a general algorithm to implement and manage such large scale problems.

Theory of the colossal Van-der-Waals binding in soft and hard condensed matter

Georgiev, Mladen; Gochev, Alexander; Singh, Jai
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 12/10/2005
Relevância na Pesquisa
65.6%
A simple theory is proposed for the dispersive molecular binding of unusually high magnitude due to an enhanced polarizability. Two alternative ways have so far been considered in the literature leading to the polarizability enhancement: (i) a vibronic energy level gap narrowing, as proposed by us with regard to a hypothetical exciton matter, and (ii) a giant electric dipole in a Rydberg state of constituent atoms, as proposed by Gilman with regard to an enigmatic substance building the ball lightning. We now combine the two mechanisms to obtain concrete expressions for the colossal binding energy. The problem is exemplified for a three-level system coupled to the umbrella mode of an ammonia molecule. Other possibilities for the design of enhanced-polarizability molecules are also discussed. The colossal Van-der-Waals binding is most likely to materialize in hard condensed matter and perhaps less so in soft condensed matter.; Comment: 20 pages, 3 figures, pdf format

Proceedings of the 35th Annual Australian/New Zealand Condensed Matter and Materials Meeting

Radhanpura, K.; Hargreaves, S.; Lewis, R. A.; Krüger, H.; Rey, E.; Si, P. -Z.; Söhnel, T.; Jovic, V.; Metson, J. B.; Waterhouse, G. I. N.; Abiona, A. A.; Kemp, W. J.; Byrne, A. P.; Ridgeway, M. C.; Timmers, H.; Cashion, J. D.; Gates, W. P.; Greaves, T.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 18/07/2011
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65.59%
The 35th Australian/New Zealand Annual Condensed Matter and Materials Meeting was held at the Charles Sturt University campus in Wagga Wagga, NSW, Australia from the 1st to the 4th of February 2011. The conference was attended by 92 delegates from a range of universities across Australia, New Zealand and further afield. There were a total of 9 invited and 21 contributed talks during the three days of scientific sessions, as well as 2 poster sessions with a total of 49 poster presentations. All presenters were invited to submit a manuscript for publication in the conference proceedings. The length limits where six pages for invited papers and four pages for contributed papers. Each manuscript was reviewed by two anonymous referees and 18 papers were accepted for publication. The accepted manuscripts are also available at the online publication section of the Australian Institute of Physics national web site (http://www.aip.org.au/).; Comment: A.P. Micolich (Editor), ISBN 978-0-646-55969-8 (2011). 18 papers from 35th Australian/New Zealand Annual Condensed Matter and Materials Meeting, 85 pages

Multipurpose High Frequency Electron Spin Resonance Spectrometer for Condensed Matter Research

Nagy, Kalman L; Quintavalle, Dario; Feher, Titusz; Janossy, Andras
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 29/10/2009
Relevância na Pesquisa
65.57%
We describe a quasi-optical multifrequency ESR spectrometer operating in the 75-225 GHz range and optimized at 210 GHz for general use in condensed matter physics, chemistry and biology. The quasi-optical bridge detects the change of mm wave polarization at the ESR. A controllable reference arm maintains a mm wave bias at the detector. The attained sensitivity of 2x10^10 spin/G/(Hz)1/2, measured on a dilute Mn:MgO sample in a non-resonant probe head at 222.4 GHz and 300 K, is comparable to commercial high sensitive X band spectrometers. The spectrometer has a Fabry-Perot resonator based probe head to measure aqueous solutions, and a probe head to measure magnetic field angular dependence of single crystals. The spectrometer is robust and easy to use and may be operated by undergraduate students. Its performance is demonstrated by examples from various fields of condensed matter physics.; Comment: submitted to Journal of Magnetic Resonance

Atomistic misconception of current model for condensed matter evaporation and new formulation

Semak, V. V.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 20/05/2014
Relevância na Pesquisa
65.59%
Even though the phenomenon of evaporation is omnipresent and has immense scientific and technological importance, the research effort to unveil its fundamentals remains inadequately low. As one particular consequence, the textbooks and educational courses are lacking detailed explanation of evaporation and its effects. In order to advance fundamental theory of evaporation and increase accuracy of evaporation simulation a novel evaporation theory is presented. This integrated Atomistic(Molecular)-Kinetics-Gasdynamics theoretical model that combines statistical mechanics, gas dynamics and thermodynamics approaches opens a path to detailed description of nonstationary, nonequilibrium evaporation of condensed matter. The main innovation of the proposed approach is that, unlike all previous and current models of evaporation that are based on the assumption of evaporation as emission of the particles that are not bound within the condense phase, the described new model treats evaporation of condensed phase as escape of the particles of sufficient kinetic energy out of potential well located at the boundary of condensed and gaseous phases. Correspondingly, the re-condensation of the vapor onto the surface is treated as entrapment of the vapor particles with kietic energy lower than the depth of the potential well. The described novel research will open new opportunities to substantially advance our knowledge and provide needed contributions to chemical...

What can gauge-gravity duality teach us about condensed matter physics?

Sachdev, Subir
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
65.58%
I discuss the impact of gauge-gravity duality on our understanding of two classes of systems: conformal quantum matter and compressible quantum matter. The first conformal class includes systems, such as the boson Hubbard model in two spatial dimensions, which display quantum critical points described by conformal field theories. Questions associated with non-zero temperature dynamics and transport are difficult to answer using conventional field theoretic methods. I argue that many of these can be addressed systematically using gauge-gravity duality, and discuss the prospects for reliable computation of low frequency correlations. Compressible quantum matter is characterized by the smooth dependence of the charge density, associated with a global U(1) symmetry, upon a chemical potential. Familiar examples are solids, superfluids, and Fermi liquids, but there are more exotic possibilities involving deconfined phases of gauge fields in the presence of Fermi surfaces. I survey the compressible systems studied using gauge-gravity duality, and discuss their relationship to the condensed matter classification of such states. The gravity methods offer hope of a deeper understanding of exotic and strongly-coupled compressible quantum states.; Comment: 34 pages...

Thermodynamic QED Coherence in Condensed Matter: Microscopic Basis of Thermal Superradiance

Sivasubramanian, S.; Widom, A.; Srivastava, Y. N.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/09/2002
Relevância na Pesquisa
65.59%
Electromagnetic superradiant field coherence exists in a condensed matter system if the electromagnetic field oscillators undergo a mean displacement. Transitions into thermal states with ordered superradiant phases have been shown to theoretically exist in Dicke-Preparata models. The theoretical validity of these models for condensed matter has been called into question due to non-relativistic diamagnetic terms in the electronic Hamiltonian. The microscopic bases of Dicke-Preparata thermal superradiance for realistic macroscopic systems are explored in this work. The impossibility of diaelectric correlations in condensed matter systems (via the Landau-Lifshitz theorem) provides a strong theoretical basis for understanding the physical reality of condensed matter thermodynamic superradiant phases.; Comment: 11 pages, no figures, LaTeX format

Superfluid Helium 3: Link between Condensed Matter Physics and Particle Physics

Vollhardt, D.; Woelfle, P.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 05/12/2000
Relevância na Pesquisa
65.57%
The discovery of the superfluid phases of Helium 3 in 1971 opened the door to one of the most fascinating systems known in condensed matter physics. Superfluidity of Helium 3, originating from pair condensation of Helium 3 atoms, turned out to be the ideal testground for many fundamental concepts of modern physics, such as macroscopic quantum phenomena, (gauge-)symmetries and their spontaneous breakdown, topological defects, etc. Thereby the superfluid phases of Helium 3 enriched condensed matter physics enormously. In particular, they contributed significantly - and continue to do so - to our understanding of various other physical systems, from heavy fermion and high-Tc superconductors all the way to neutron stars, particle physics, gravity and the early universe. A simple introduction into the basic concepts and questions is presented.; Comment: 11 pages, 2 figures; to be published in Acta Physica Polonica B [Proceedings of the XL Jubilee Cracow School of Theoretical Physics on "Quantum Phase Transitions in High Energy and Condensed Matter Physics"; 3-11 June, 2000, Zakopane, Poland]

Random First Order Theory concepts in Biology and Condensed Matter physics

Kirkpatrick, T. R.; Thirumalai, D.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 15/12/2014
Relevância na Pesquisa
65.57%
The routine transformation of a liquid, as it is cooled rapidly, resulting in glass formation, is remarkably complex. A theoretical explanation of the dynamics associated with this process has remained one of the major unsolved problems in condensed matter physics. The Random First Order Transition (RFOT) theory, which was proposed over twenty five years ago, provides a theoretical basis for explaining much of the phenomena associated with glass forming materials. It links or relates multiple metastable states, slow or glassy dynamics, dynamic heterogeneity, and both a dynamical and an ideal glass transition. Remarkably, the major concepts in the RFOT theory can also be profitably used to understand many spectacular phenomena in biology and condensed matter physics, as we illustrate here. The presence of a large number of metastable states and the dynamics in such complex landscapes in biological systems from molecular to cellular scale and beyond leads to behavior, which is amenable to descriptions based on the RFOT theory. Somewhat surprisingly even intratumor heterogeneity arising from variations in cancer metastasis in different cells is hauntingly similar to glassy systems. There are also deep connections between glass physics and electronically disordered systems undergoing a metal-insulator transition...

An Introduction to Gauge Gravity Duality and Its Application in Condensed Matter

Green, Andrew G.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 22/04/2013
Relevância na Pesquisa
65.57%
The past few years have witnessed a remarkable crossover of string theoretical ideas from the abstract world of geometrical forms to the concrete experimental realm of condensed matter physics. The basis for this --- variously known as holography, the AdS/CFT correspondence or gauge-gravity duality --comes from notions right at the cutting edge of string theory. Nevertheless, the insights afforded can often be expressed in ways very familiar to condensed matter physicists, such as relationships between response functions and new sum rules. The aim of this short, introductory review is to survey the ideas underpinning this crossover, in a way that -- as far as possible -- strips them of sophisticated mathematical formalism, whilst at the same time retaining their fundamental essence. I will sketch the areas in which progress has been made to date and highlight where the challenges and open questions lie. Finally, I will attempt to give a perspective upon these ideas. What contribution can we realistically expect from this approach and how might it be accommodated into the canon of condensed matter theory? Inevitably, any attempt to do this in such a rapidly evolving field will be superseded by events. Nevertheless, I hope that this will provide a useful way to think about gauge-gravity duality and the uncharted directions in which it might take us.; Comment: Unedited version of article published in Contemporary Physics. Intended for advanced final-year undergraduates

The Fermi Gases and Superfluids: Short Review of Experiment and Theory for Condensed Matter Physicists

Levin, K.; Hulet, Randall G.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 09/02/2012
Relevância na Pesquisa
65.58%
The study of ultracold atomic Fermi gases is a rapidly exploding subject which is defining new directions in condensed matter and atomic physics. Quite generally what makes these gases so important is their remarkable tunability and controllability. Using a Feshbach resonance one can tune the attractive two-body interactions from weak to strong and thereby make a smooth crossover from a BCS superfluid of Cooper pairs to a Bose-Einstein condensed superfluid. Furthermore, one can tune the population of the two spin states, allowing observation of exotic spin-polarized superfluids, such as the Fulde Ferrell Larkin Ovchinnikov (FFLO) phase. A wide array of powerful characterization tools, which often have direct condensed matter analogues, are available to the experimenter. In this Chapter, we present a general review of the status of these Fermi gases with the aim of communicating the excitement and great potential of the field.; Comment: 34 pages, 15 figures. To appear as a chapter in "Contemporary Concepts of Condensed Matter Science", Elsevier

Shock (Blast) Mitigation by "Soft" Condensed Matter

Nesterenko, Vitali F.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
65.6%
It is a common point that "soft" condensed matter (like granular materials or foams) can reduce damage caused by impact or explosion. It is attributed to their ability to absorb significant energy. This is certainly the case for a quasistatic type of deformation at low velocity of impact where such materials are widely used for packing of fragile devices. At the same time a mitigation of blast phenomena must take into account shock wave properties of "soft" matter which very often exhibit highly nonlinear, highly heterogeneous and dissipative behavior. This paper considers applications of "soft" condensed matter for blast mitigation using simplified approach, presents analysis of some anomalous effects and suggestions for future research in this exciting area.; Comment: 12 pages, 12 figures

Non-equilibrium phase transitions in condensed matter and cosmology: spinodal decomposition, condensates and defects

Boyanovsky, D.; de Vega, H. J.; Holman, R.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/03/1999
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65.59%
These lectures address the dynamics of phase ordering out of equilibrium in condensed matter and in quantum field theory in cosmological settings, emphasizing their similarities and differences. In condensed matter we describe the phenomenological approach based on the Time Dependent Ginzburg-Landau (TDGL) description. After a general discussion of the main experimental and theoretical features of phase ordering kinetics and the description of linear (spinodal) instabilities we introduce the scaling hypothesis and show how a dynamical correlation length emerges in the large N limit in condensed matter systems. The large N approximation is a powerful tool in quantum field theory that allows the study of non-perturbative phenomena in a consistent manner. We study the exact solution to the dynamics after a quench in this limit in Minkowski space time and in radiation dominated Friedman-Robertson-Walker Cosmology. There are some remarkable similarities between these very different settings such as the emergence of a scaling regime and of a dynamical correlation length at late times that describe the formation and growth of ordered regions. In quantum field theory and cosmology this length scale is constrained by causality and its growth in time is also associated with coarsening and the onset of a condensate. We provide a density matrix interpretation of the formation of defects and the classicalization of quantum fluctuations.; Comment: 23 pages (revtex)...

Planetary Atmospheres as Non-Equilibrium Condensed Matter

Marston, J. B.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
65.59%
Planetary atmospheres, and models of them, are discussed from the viewpoint of condensed matter physics. Atmospheres are a form of condensed matter, and many interesting phenomena of condensed matter systems are realized by them. The essential physics of the general circulation is illustrated with idealized 2-layer and 1-layer models of the atmosphere. Equilibrium and non-equilibrium statistical mechanics are used to directly ascertain the statistics of these models.; Comment: 23 pages, 10 figures, to appear in Annual Reviews of Condensed Matter Physics (2012). Rhines scale (Eq. 25) corrected, one reference moved, and updates to other citations