SLOW DYNAMICS IN SPIN GLASSES AND OTHER COMPLEX SYSTEMS

1992 ◽  
pp. 207-236 ◽  
Author(s):  
E. Vincent ◽  
J. Hammann ◽  
M. Ocio
Keyword(s):  
Complex Systems ◽  
Spin Glasses ◽  
Slow Dynamics

Are Spin Glasses Complex Systems?

2013 ◽  
Author(s):  
Daniel L. Stein ◽  
Charles M. Newman
Keyword(s):  
Complex Systems ◽  
Spin Glass ◽  
Spin Glasses ◽  
Current Understanding ◽  
Recent Developments ◽  
Glass Science ◽  
Warren Weaver

This chapter considers how spin glass science fits into the larger area of complexity studies. It discusses three landmark papers in the field of complexity, by Warren Weaver, Herb Simon, and Phil Anderson, respectively, and examines how the ideas they introduced might relate to the current understanding of spin glasses. It also takes a brief look at recent developments, in particular various proposals for measures of complexity, and considers how they might illuminate some features of spin glasses. It concludes by asking whether spin glasses can still be thought of as “complex systems,” and in so doing introduces a proposal for a kind of “new complexity” as it relates to spin glasses.

Slow dynamics in the geometrically frustrated magnetZnFe2O4: Universal features of aging phenomena in spin glasses

2014 ◽  
Vol 90 (1) ◽  
Author(s):  
H. Mamiya ◽  
N. Tsujii ◽  
N. Terada ◽  
S. Nimori ◽  
H. Kitazawa ◽  
...  
Keyword(s):  
Spin Glasses ◽  
Slow Dynamics ◽  
Geometrically Frustrated ◽  
Aging Phenomena

Magnetic Sans of Nanoparticles and Complex Systems

2021 ◽  
pp. 172-222
Author(s):  
Andreas Michels
Keyword(s):  
Boundary Value Problem ◽  
Complex Systems ◽  
Spin Glasses ◽  
Boundary Value ◽  
Vortex State ◽  
Amorphous Magnets ◽  
Analytical Expressions ◽  
Complete Specification

This chapter provides an overview on the magnetic SANS of nanoparticles and complex systems, which include ferrofluids, magnetic steels, and spin glasses and amorphous magnets. The underlying assumptions of the conventional particle-matrix-based model of magnetic SANS, which assumes uniformly magnetized domains, characteristic e.g., for superparamagnets, are discussed and we provide a complete specification of the micromagnetic boundary-value problem. First attempts to provide analytical expressions for the vortex-state-related magnetic SANS of thin circular discs are considered.

scholarly journals Disorder and fluctuations in complex physical systems: Nobel Prize winner in physics 2021 Giorgio Parisi

2021 ◽  
Vol 6 (4) ◽  
pp. 243-246
Author(s):  
Vyacheslav M. Tyutyunnik
Keyword(s):  
Complex Systems ◽  
Nobel Prize ◽  
Spin Glasses ◽  
Physical Modelling ◽  
Nobel Prize Winner ◽  
Complex Materials ◽  
Physical Systems ◽  
Nobel Prize In Physics ◽  
Hidden Patterns ◽  
Earth’S Climate

In 2021, the Nobel Prize in Physics was awarded “for innovative contributions to our understanding of complex systems,” with half awarded jointly to Shukuro Manabe and Klaus Hasselmann “for the physical modelling of Earth’s climate, quantifying variability and reliably predicting global warming”, and the other half to Giorgio Parisi “for the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales”. Parisi discovered hidden patterns in disordered, complex materials. His discoveries are one of the most important contributions to the theory of complex systems. He proved that equilibrium is never achieved in spin glasses, because frustrations do not allow all limitations to be satisfied. In reality, there are an infinite number of practically equilibrium states in which frustrations tend to a minimum. Parisi’s research interests cover 14 different directions.

Aging and Glassy Dynamics in Complex Systems: Some Theoretical Ideas

1994 ◽  
Vol 367 ◽  
Author(s):  
Jean-Philippe Bouchaud
Keyword(s):  
Complex Systems ◽  
Power Law ◽  
Spin Glasses ◽  
A Priori ◽  
Mean Field ◽  
Observation Time ◽  
Spin Glass Phase ◽  
Power Law Decay ◽  
Small Times ◽  
Keywords Aging

AbstractWe discuss some recent experimental results on the non-stationary dynamics of spin-glasses, which serves as an excellent laboratory for other complex systems. Inspired from Parisi's mean-field solution, we propose that the dynamics of these systems can be though of as a random walk in phase space, between traps characterized by trapping time distribution decaying as a power law. The average exploration time diverges in the spin-glass phase, naturally leading to time-dependent dynamics with a charateristic time scale fixed by the observation time tw itself (aging). By the same token, we find that the correlation function (or the magnetization) decays as a stretched exponential at small times t ≪ tw crossing over to power-law decay at large times t ≫ tw. Finally, we discuss recent speculations on the relevance of these concepts to real glasses, where quenched disorder is a priori absent. Keywords: Aging, slow dynamics, spin-glasses, glasses.

scholarly journals Spin Anisotropy and Slow Dynamics in Spin Glasses

2004 ◽  
Vol 92 (16) ◽  
Author(s):  
F. Bert ◽  
V. Dupuis ◽  
E. Vincent ◽  
J. Hammann ◽  
J.-P. Bouchaud
Keyword(s):  
Spin Glasses ◽  
Slow Dynamics

Relaxation and aging in spin glasses and other complex systems

1990 ◽  
Vol 80 (3) ◽  
pp. 429-438 ◽  
Author(s):  
Karl Heinz Hoffmann ◽  
Paolo Sibani
Keyword(s):  
Complex Systems ◽  
Spin Glasses

DRIVEN TRANSITIONS AT THE ONSET OF ERGODICITY BREAKING IN GAUGE-INVARIANT COMPLEX NETWORKS

2010 ◽  
Vol 24 (30) ◽  
pp. 5995-6011 ◽  
Author(s):  
ADRIANO BARRA
Keyword(s):  
Complex Systems ◽  
Spin Glasses ◽  
Order Parameter ◽  
Degrees Of Freedom ◽  
Driving Mechanism ◽  
Strong Correlations ◽  
Gauge Invariant ◽  
Underlying Network ◽  
Ergodicity Breaking ◽  
Naive Approach

In the last few years, the statistical mechanics of spin glasses has become one of the major frameworks for analyzing the macroscopical equilibrium properties of complex systems starting from the microscopical dynamics of their components. Recently, many advances in its rigorous formulation without the replica trick have been achieved, highlighting the importance of this field of research in our understanding of complex systems. In this framework we analyze the critical behavior of a Poissonian diluted network with random competitive interactions among gauge-invariant dichotomic variables pasted on the nodes (i.e., a suitable version of the Viana–Bray diluted spin glass). The model is described by an infinite series of order parameters (the multioverlaps) and has two degrees of freedom: the temperature (which can be thought of as the noise level) and the connectivity (the averaged number of links per node in the underlying network). In this paper, we show that there are not several transition lines, one for every order parameter, as a naive approach would suggest but just one corresponding to ergodicity breaking. We explain this scenario within a novel and simple mathematical technique: we show the existence of a driving mechanism such that, as the first order parameter (the two-replica overlap) becomes different from zero due to a real second order phase transition, it enforces all the other multioverlaps toward positive values thanks to the strong correlations which develop among themselves and the two-replica overlap at the critical line. These correlations are ultimately related — within our framework — to the breaking of the gauge invariance of the Boltzmann state at the boundary of the ergodic region. A discussion on the structure of the free energy, fundamental macroscopical observable by which the whole thermodynamic can be achieved, is also presented.

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