Naslov
Activated dynamic scaling in the random-field Ising model : A nonperturbative functional renormalization group approach

Autori
Balog, Ivan ; Tarjus, Gilles

Izvornik
Physical Review B - Condensed Matter and Materials Physics (1098-0121) 91 (2015); 214201-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Critical phenomena; disordered systems; renormalization group

Sažetak
The random-field Ising model shows an extreme critical slowdown that has been described by activated dynamic scaling: The characteristic time of relaxation toward equilibrium diverges exponentially with the correlation length lnτ∼ξψ/T, with ψ an a priori unknown barrier exponent. Through a nonperturbative functional renormalization group, we show that for spatial dimensions d less than a critical value dDR≃5.1, also associated with dimensional-reduction breakdown, ψ=θ with θ the temperature exponent near the zero-temperature fixed point that controls the critical behavior. For d>dDR, on the other hand, ψ=θ−2λ, where θ=2 and λ>0 an additional exponent. At the upper critical dimension d=6, λ=1, so that ψ=0, and activated scaling gives way to conventional scaling. We give a physical interpretation of the results in terms of collective events in real space, avalanches, and droplets. We also propose a way to check the two regimes by computer simulations of long-range one-dimensional systems.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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