scholarly journals Emergent phenomena at multiferroic heterointerfaces

2012 ◽  
Vol 370 (1977) ◽  
pp. 4856-4871 ◽  
Author(s):  
P. Yu ◽  
Y. H. Chu ◽  
R. Ramesh
Keyword(s):  
Degrees Of Freedom ◽  
Magnetic State ◽  
Model Systems ◽  
Current Understanding ◽  
Interesting Phenomenon ◽  
Future Studies ◽  
Exotic States ◽  
Emergent Phenomena ◽  
Open Questions ◽  
Multiferroic Bifeo

The coupling and reconstruction of electronic degrees of freedom (such as charge, spin and orbital) at a heterointerface can lead to unexpected and exotic states of matter. In this study, using model systems consisting of multiferroic BiFeO 3 and ferromagnetic La 0.7 Sr 0.3 MnO 3 , we review the current understanding of a novel interfacial magnetic state formed at the interface, and highlight some possible mechanisms responsible for this interesting phenomenon and identify open questions for future studies.

Excitonic Coupled-cluster Theory: Part I, General Formalism

2017 ◽  
Author(s):  
Yuhong Liu ◽  
Anthony Dutoi
Keyword(s):  
Electron Correlation ◽  
Degrees Of Freedom ◽  
Model Systems ◽  
Coupled Cluster ◽  
Effective Hamiltonian ◽  
Coupled Cluster Theory ◽  
Cluster Theory ◽  
Companion Article ◽  
High Level ◽  
Fragment Interaction

<div> <div>A shortcoming of presently available fragment-based methods is that electron correlation (if included) is described at the level of individual electrons, resulting in many redundant evaluations of the electronic relaxations associated with any given fluctuation. A generalized variant of coupled-cluster (CC) theory is described, wherein the degrees of freedom are fluctuations of fragments between internally correlated states. The effects of intra-fragment correlation on the inter-fragment interaction is pre-computed and permanently folded into the effective Hamiltonian. This article provides a high-level description of the CC variant, establishing some useful notation, and it demonstrates the advantage of the proposed paradigm numerically on model systems. A companion article shows that the electronic Hamiltonian of real systems may always be cast in the form demanded. This framework opens a promising path to build finely tunable systematically improvable methods to capture precise properties of systems interacting with a large number of other systems. </div> </div>

Excitonic Coupled-cluster Theory: Part I, General Formalism

2017 ◽  
Author(s):  
Yuhong Liu ◽  
Anthony Dutoi
Keyword(s):  
Electron Correlation ◽  
Degrees Of Freedom ◽  
Model Systems ◽  
Coupled Cluster ◽  
Effective Hamiltonian ◽  
Coupled Cluster Theory ◽  
Cluster Theory ◽  
Companion Article ◽  
High Level ◽  
Fragment Interaction

<div> <div>A shortcoming of presently available fragment-based methods is that electron correlation (if included) is described at the level of individual electrons, resulting in many redundant evaluations of the electronic relaxations associated with any given fluctuation. A generalized variant of coupled-cluster (CC) theory is described, wherein the degrees of freedom are fluctuations of fragments between internally correlated states. The effects of intra-fragment correlation on the inter-fragment interaction is pre-computed and permanently folded into the effective Hamiltonian. This article provides a high-level description of the CC variant, establishing some useful notation, and it demonstrates the advantage of the proposed paradigm numerically on model systems. A companion article shows that the electronic Hamiltonian of real systems may always be cast in the form demanded. This framework opens a promising path to build finely tunable systematically improvable methods to capture precise properties of systems interacting with a large number of other systems. </div> </div>

scholarly journals The interiors of Uranus and Neptune: current understanding and open questions

2020 ◽  
Vol 378 (2187) ◽  
pp. 20190474 ◽  
Author(s):  
Ravit Helled ◽  
Jonathan J. Fortney
Keyword(s):  
Solar System ◽  
Internal Structure ◽  
Planetary Systems ◽  
Space Missions ◽  
Current Understanding ◽  
Interior Structure ◽  
Distinct Class ◽  
Open Questions

Uranus and Neptune form a distinct class of planets in our Solar System. Given this fact, and ubiquity of similar-mass planets in other planetary systems, it is essential to understand their interior structure and composition. However, there are more open questions regarding these planets than answers. In this review, we concentrate on the things we do not know about the interiors of Uranus and Neptune with a focus on why the planets may be different, rather than the same. We next summarize the knowledge about the planets’ internal structure and evolution. Finally, we identify the topics that should be investigated further on the theoretical front as well as required observations from space missions. This article is part of a discussion meeting issue ‘Future exploration of ice giant systems’.

scholarly journals Emergent colloidal currents across ordered and disordered landscapes

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Dominik Lips ◽  
Ralph L. Stoop ◽  
Philipp Maass ◽  
Pietro Tierno
Keyword(s):  
Magnetic Particles ◽  
Lattice Gas ◽  
Solvable Model ◽  
Model Systems ◽  
Suitable Model ◽  
Many Body ◽  
Emergent Phenomena ◽  
Density Relationship ◽  
Far From Equilibrium ◽  
Experimental Findings

AbstractMany-particle effects in driven systems far from equilibrium lead to a rich variety of emergent phenomena. Their classification and understanding often require suitable model systems. Here we show that microscopic magnetic particles driven along ordered and defective lattices by a traveling wave potential display a nonlinear current-density relationship, which arises from the interplay of two effects. The first one originates from particle sizes nearly commensurate with the substrate in combination with attractive pair interactions. It governs the colloidal current at small densities and leads to a superlinear increase. We explain such effect by an exactly solvable model of constrained cluster dynamics. The second effect is interpreted to result from a defect-induced breakup of coherent cluster motion, leading to jamming at higher densities. Finally, we demonstrate that a lattice gas model with parallel update is able to capture the experimental findings for this complex many-body system.

HOLOGRAPHIC SPACETIME

2012 ◽  
Vol 21 (11) ◽  
pp. 1241004 ◽  
Author(s):  
TOM BANKS
Keyword(s):  
String Theory ◽  
Degrees Of Freedom ◽  
Good Description ◽  
De Sitter ◽  
Finite Radius ◽  
Full Field ◽  
Mass Scaling ◽  
Finite Dimensional ◽  
Emergent Phenomena ◽  
Holographic Screen

The theory of holographic spacetime (HST) generalizes both string theory and quantum field theory (QFT). It provides a geometric rationale for supersymmetry (SUSY) and a formalism in which super-Poincare invariance follows from Poincare invariance. HST unifies particles and black holes, realizing both as excitations of noncommutative geometrical variables on a holographic screen. Compact extra dimensions are interpreted as finite-dimensional unitary representations of super-algebras, and have no moduli. Full field theoretic Fock spaces, and continuous moduli are both emergent phenomena of super-Poincare invariant limits in which the number of holographic degrees of freedom goes to infinity. Finite radius de Sitter (dS) spaces have no moduli, and break SUSY with a gravitino mass scaling like Λ1/4. In regimes where the Covariant Entropy Bound is saturated, QFT is not a good description in HST, and inflation is such a regime. Following ideas of Jacobson, the gravitational and inflaton fields are emergent classical variables, describing the geometry of an underlying HST model, rather than "fields associated with a microscopic string theory". The phrase in quotes is meaningless in the HST formalism, except in asymptotically flat and AdS spacetimes, and some relatives of these.

scholarly journals Cutaneous neurofibromas in the genomics era: current understanding and open questions

2018 ◽  
Vol 118 (12) ◽  
pp. 1539-1548 ◽  
Author(s):  
Robert J. Allaway ◽  
Sara J. C. Gosline ◽  
Salvatore La Rosa ◽  
Pamela Knight ◽  
Annette Bakker ◽  
...  
Keyword(s):  
Current Understanding ◽  
Open Questions ◽  
Cutaneous Neurofibromas

Hypnosis and relaxation

2013 ◽  
pp. 560-568 ◽  
Author(s):  
Christina Liossi ◽  
Leora Kuttner ◽  
Chantal Wood ◽  
Lonnie K. Zeltzer
Keyword(s):  
Chronic Pain ◽  
Clinical Practice ◽  
Pain Management ◽  
Research Evidence ◽  
Research Literature ◽  
Current Understanding ◽  
Relaxation Techniques ◽  
Chronic Pain Management ◽  
Future Studies ◽  
Hypnotic Analgesia

This chapter discusses the current research literature and clinical practice regarding the use of hypnosis in paediatric pain management, first defining hypnosis and discussing theoretical conceptualizations. Next it presents our current understanding of the mechanisms of hypnotic analgesia, along with the research evidence for the efficacy of hypnosis in the control of acute and chronic paediatric pain; in both sections relevant clinical techniques are discussed. It also includes a description and discussion of different relaxation techniques and the evidence for their efficacy in acute and chronic pain management, and concludes with an attempt to summarize and evaluate the existing literature and make suggestions for future studies and clinical practice.

Modular Distributed Models of Engineering Structures

2003 ◽  
Author(s):  
Clark J. Radcliffe ◽  
Jon Sticklen
Keyword(s):  
Engineering Design ◽  
Degrees Of Freedom ◽  
Structural Model ◽  
Integrated Design ◽  
Model Systems ◽  
Structural Stiffness ◽  
Engineering Structures ◽  
Distributed Modeling ◽  
Communications Network ◽  
Component Models

Approaches to engineering design and manufacturing such as integrated design and manufacture and just in time fabrication depend on interaction with and among component supply companies that most often use very diverse technologies. The Internet Engineering Design Agents (i-EDA) software system uses a distributed, component-based, agent methodology that is realized following a strong black box approach to modeling. An individual Design Agent (DA) is a virtual product capable of encapsulating both descriptive and model based information about the product it represents. Hierarchically recursive agents for sub-systems and/or components are linked via a communications network to form larger integrated model systems. A two dimensional bridge system structural model is used as an example to illustrate the distributed assembly of structural models from components registered as DA’s on a communications network. Modular Distributed Modeling (MDM) of engineering structures performs static deflection analysis using traditional, fixed causality, structural stiffness models. This paper presents the methodology required to assemble traditional structural stiffness models provided by internet agents representing structural components. The methodology discussed assembles these component models into the structural stiffness model of an assembly distributed by an agents represent that physical assembly of components. Using this modular distributed modeling method; models of complex assemblies can be built and distributed while hiding the topology and characteristics of their structural subassemblies. The automated, modular, assembly of structural stiffness models will be derived for discrete physical connections. Discrete connections are important to the assembly of components such as truss and shaft structures where the relationship between component displacements involve discrete, matching, degrees of freedom on components to be assembled. Specific examples of discrete assembly of truss bridge component models will be presented.

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