scholarly journals Nature of the Spin Glass Phase in Finite Dimensional (Ising) Spin Glasses

2020 ◽  
pp. 1-52
Author(s):  
Juan J. Ruiz-Lorenzo
Keyword(s):  
Spin Glass ◽  
Spin Glasses ◽  
Glass Phase ◽  
Spin Glass Phase ◽  
Ising Spin ◽  
Finite Dimensional

scholarly journals Ergodic and localized regions in quantum spin glasses on the Bethe lattice

2017 ◽  
Vol 375 (2108) ◽  
pp. 20160424 ◽  
Author(s):  
G. Mossi ◽  
A. Scardicchio
Keyword(s):  
Spin Glass ◽  
Spin Glasses ◽  
Quantum Dynamics ◽  
Bethe Lattice ◽  
Transverse Field ◽  
Quantum Systems ◽  
Quantum Spin ◽  
Many Body ◽  
Spin Glass Phase ◽  
Ising Spin

By considering the quantum dynamics of a transverse-field Ising spin glass on the Bethe lattice, we find the existence of a many-body localized (MBL) region at small transverse field and low temperature. The region is located within the thermodynamic spin glass phase. Accordingly, we conjecture that quantum dynamics inside the glassy region is split into a small MBL region and a large delocalized (but not necessarily ergodic) region. This has implications for the analysis of the performance of quantum adiabatic algorithms. This article is part of the themed issue ‘Breakdown of ergodicity in quantum systems: from solids to synthetic matter’.

scholarly journals Influence of Concentration Fluctuations on Relaxation Processes in Spin Glasses

2018 ◽  
Vol 2 (4) ◽  
pp. 26 ◽  
Author(s):  
Julia Wagner ◽  
Wolfgang Häußler ◽  
Olaf Holderer ◽  
Andreas Bauer ◽  
Stephen Shapiro ◽  
...  
Keyword(s):  
Phase Transition ◽  
Spin Glass ◽  
Spin Glasses ◽  
Glass Phase ◽  
Concentration Fluctuations ◽  
Neutron Resonance ◽  
Relaxation Processes ◽  
Local Concentration ◽  
Spin Glass Phase ◽  
Resonance Spin

Using the unique combination of atomically resolved atom probe tomography (APT) and volume averaged neutron (resonance) spin echo (NRSE and NSE) experiments, the influence of nano-scaled clusters on the spin relaxation in spin glasses was studied. For this purpose, the phase transition from the paramagnetic phase to the spin glass phase in an Fe-Cr spin glass with a composition of Fe 17 . 8 Cr 82 . 2 was studied in detail by means of NRSE. The microstructure was characterised by APT measurements, which show local concentration fluctuations of Fe and Cr on a length scale of 2 to 5 nm, which lead (i) to the coexistence of ferro- and anti-ferromagnetic clusters and (ii) a change of the magnetic properties of the whole sample, even in the spin glass phase, where spins are supposed to be randomly frozen. We show that a generalized spin glass relaxation function, which was successfully used to describe the phase transition in diluted spin glasses, can also be used for fitting the spin dynamics in spin glasses with significant concentration fluctuations.

scholarly journals A statics-dynamics equivalence through the fluctuation–dissipation ratio provides a window into the spin-glass phase from nonequilibrium measurements

2017 ◽  
Vol 114 (8) ◽  
pp. 1838-1843 ◽  
Author(s):  
Marco Baity-Jesi ◽  
Enrico Calore ◽  
Andres Cruz ◽  
Luis Antonio Fernandez ◽  
José Miguel Gil-Narvión ◽  
...  
Keyword(s):  
Spin Glass ◽  
Glass Phase ◽  
Large Scale ◽  
Infinite Systems ◽  
Spin Glass Phase ◽  
Ising Spin ◽  
Fluctuation Dissipation ◽  
Equilibrium Probability ◽  
Large Scale Simulations ◽  
Nonequilibrium Fluctuation

We have performed a very accurate computation of the nonequilibrium fluctuation–dissipation ratio for the 3D Edwards–Anderson Ising spin glass, by means of large-scale simulations on the special-purpose computers Janus and Janus II. This ratio (computed for finite times on very large, effectively infinite, systems) is compared with the equilibrium probability distribution of the spin overlap for finite sizes. Our main result is a quantitative statics-dynamics dictionary, which could allow the experimental exploration of important features of the spin-glass phase without requiring uncontrollable extrapolations to infinite times or system sizes.

Spin glasses: recent advances in mean-field theory

1987 ◽  
Vol 65 (10) ◽  
pp. 1245-1250 ◽  
Author(s):  
B. W. Southern
Keyword(s):  
Field Theory ◽  
Spin Glasses ◽  
Glass Phase ◽  
Mean Field Theory ◽  
Mean Field ◽  
Three Dimensional ◽  
Spin Glass Phase ◽  
Ising Spin ◽  
Recent Advances ◽  
The Mean

A survey of recent advances in the mean-field theory of Ising spin glasses is presented. The physical picture of the spin-glass phase predicted by this theory is described, and its relationship to real three-dimensional systems is discussed.

scholarly journals Delocalization transition in low energy excitation modes of vector spin glasses

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Silvio Franz ◽  
Flavio Nicoletti ◽  
Giorgio Parisi ◽  
Federico Ricci-Tersenghi
Keyword(s):  
Spin Glass ◽  
Spin Glasses ◽  
Glass Phase ◽  
Paramagnetic Phase ◽  
Cavity Method ◽  
Zero Temperature ◽  
Energy Excitation ◽  
Spin Glass Phase ◽  
Glass Model ◽  
Fully Connected

We study the energy minima of the fully-connected mm-components vector spin glass model at zero temperature in an external magnetic field for m\ge 3m≥3. The model has a zero temperature transition from a paramagnetic phase at high field to a spin glass phase at low field. We study the eigenvalues and eigenvectors of the Hessian in the minima of the Hamiltonian. The spectrum is gapless both in the paramagnetic and in the spin glass phase, with a pseudo-gap behaving as \lambda^{m-1}λm−1 in the paramagnetic phase and as \sqrt{\lambda}λ at criticality and in the spin glass phase. Despite the long-range nature of the model, the eigenstates close to the edge of the spectrum display quasi-localization properties. We show that the paramagnetic to spin glass transition corresponds to delocalization of the edge eigenvectors. We solve the model by the cavity method in the thermodynamic limit. We also perform numerical minimization of the Hamiltonian for N\le 2048N≤2048 and compute the spectral properties, that show very strong corrections to the asymptotic scaling approaching the critical point.

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