Time filter

Source Type

Dresden, Germany

The Max Planck Institute for the Physics of Complex systems is one of the 80 institutes of the Max-Planck-Gesellschaft, located in Dresden, Germany. Wikipedia.

Nisoli C.,Los Alamos National Laboratory | Moessner R.,Max Planck Institute for the Physics of Complex Systems | Schiffer P.,University of Illinois at Urbana - Champaign
Reviews of Modern Physics

Frustration, the presence of competing interactions, is ubiquitous in the physical sciences and is a source of degeneracy and disorder, which in turn gives rise to new and interesting physical phenomena. Perhaps nowhere does it occur more simply than in correlated spin systems, where it has been studied in the most detail. In disordered magnetic materials, frustration leads to spin-glass phenomena, with analogies to the behavior of structural glasses and neural networks. In structurally ordered magnetic materials, it has also been the topic of extensive theoretical and experimental studies over the past two decades. Such geometrical frustration has opened a window to a wide range of fundamentally new exotic behavior. This includes spin liquids in which the spins continue to fluctuate down to the lowest temperatures, and spin ice, which appears to retain macroscopic entropy even in the low-temperature limit where it enters a topological Coulomb phase. In the past seven years a new perspective has opened in the study of frustration through the creation of artificial frustrated magnetic systems. These materials consist of arrays of lithographically fabricated single-domain ferromagnetic nanostructures that behave like giant Ising spins. The nanostructures' interactions can be controlled through appropriate choices of their geometric properties and arrangement on a (frustrated) lattice. The degrees of freedom of the material can not only be directly tuned, but also individually observed. Experimental studies have unearthed intriguing connections to the out-of-equilibrium physics of disordered systems and nonthermal "granular" materials, while revealing strong analogies to spin ice materials and their fractionalized magnetic monopole excitations, lending the enterprise a distinctly interdisciplinary flavor. The experimental results have also been closely coupled to theoretical and computational analyses, facilitated by connections to classic models of frustrated magnetism, whose hitherto unobserved aspects have here found an experimental realization. Considerable experimental and theoretical progress in this field is reviewed here, including connections to other frustrated phenomena, and future vistas for progress in this rapidly expanding field are outlined. © 2013 American Physical Society. Source

Harayama T.,Nippon Telegraph and Telephone | Shinohara S.,Max Planck Institute for the Physics of Complex Systems
Laser and Photonics Reviews

Advances in processing technology, such as quantum-well structures and dry-etching techniques, have made it possible to create new types of two-dimensional (2D) microcavity lasers which have 2D emission patterns of output laser light although conventional one-dimensional (1D) edge-emitting-type lasers have 1D emission. Two-dimensional microcavity lasers have given nice experimental stages for fundamental researches on wave chaos closely related to quantum chaos. New types of 2D microcavity lasers also can offer the important lasing characteristics of directionality and high-power output light, and they may well find applications in optical communications, integrated optical circuits, and optical sensors. Fundamental physics of 2D microcavity lasers has been reviewed from the viewpoint of classical and quantum chaos, and recently developed theoretical approaches have been introduced. In addition, nonlinear dynamics due to the interaction among wave-chaotic modes through the active lasing medium is explained. Applications of 2D microcavity lasers for directional emission with strong light confinement are introduced, as well as high-precision rotation sensors designed by using wave-chaotic properties. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Zoubi H.,Max Planck Institute for the Physics of Complex Systems
Physical Review A - Atomic, Molecular, and Optical Physics

A lattice of trapped atoms strongly coupled to a one-dimensional nanophotonic waveguide is investigated in exploiting polaritons as natural collective eigenstates. We derive polariton-polariton kinematic interactions by applying a bosonization procedure to transform excitation spin-12 operators into interacting bosons. In solving the scattering problem we extract the effective potential, which is shown to be modulated by using the excitation-photon detuning as a control parameter. We examine the regime in which polaritons behave as a dilute degenerate boson gas and in the limit where polaritons can be treated as weakly interacting photons we propose the system for realizing superfluidity of photons. We implement the kinematic interaction as a mechanism for nonlinear optical processes that provide an observation tool for the system properties, e.g., the interaction strength produces a blue shift in pump-probe experiments. © 2014 American Physical Society. Source

Zaburdaev V.,Max Planck Institute for the Physics of Complex Systems | Denisov S.,University of Augsburg | Denisov S.,Sumy State University | Klafter J.,Tel Aviv University
Reviews of Modern Physics

Random walk is a fundamental concept with applications ranging from quantum physics to econometrics. Remarkably, one specific model of random walks appears to be ubiquitous across many fields as a tool to analyze transport phenomena in which the dispersal process is faster than dictated by Brownian diffusion. The Lévy-walk model combines two key features, the ability to generate anomalously fast diffusion and a finite velocity of a random walker. Recent results in optics, Hamiltonian chaos, cold atom dynamics, biophysics, and behavioral science demonstrate that this particular type of random walk provides significant insight into complex transport phenomena. This review gives a self-consistent introduction to Lévy walks, surveys their existing applications, including latest advances, and outlines further perspectives. © 2015 American Physical Society. © 2015 American Physical Society. Source

Castelnovo C.,Royal Holloway, University of London | Moessner R.,Max Planck Institute for the Physics of Complex Systems | Sondhi S.L.,Princeton University
Annual Review of Condensed Matter Physics

The spin ice compounds Dy 2Ti 2O 7 and Ho 2Ti 2O 7 are highly unusual magnets that epitomize a set of concepts of great interest in modern condensed matter physics: Their low-energy physics exhibits an emergent gauge field and their excitations are magnetic monopoles that arise from the fractionalization of the microscopic magnetic spin degrees of freedom. In this review, we provide an elementary introduction to these concepts and we survey the thermodynamics, statics, and dynamics - in and out of equilibrium - of spin ice from these vantage points. Along the way, we touch on topics such as emergent Coulomb plasmas, observable Dirac strings, and irrational charges. We close with the outlook for these unique materials. Copyright © 2012 by Annual Reviews. All rights reserved. Source

Discover hidden collaborations