Off equilibrium dynamics in 2 d - XY system
نویسنده
چکیده
We study the non-equilibrium time evolution of the classical XY spin model in two dimensions. The two-time autocorrelation and linear response functions are considered for systems initially prepared in a high temperature state and in a completely ordered state. After a quench into the critical phase, we determine, via Monte Carlo simulations, the time-evolution of these quantities and extract the temperature dependence of the slope of the parametric plot susceptibility/correlation in the asymptotic regime. This slope is usually identified with the infinite fluctuation-dissipation ratio which measures the violation to the equilibrium fluctuation-dissipation theorem. However, a direct measure of this ratio leads to a vanishing value. PACS. 75.40.Gb Dynamic properties 05.70.Ln Non-equilibrium and irreversible thermodynamics
منابع مشابه
Dynamics of a Local Perturbation in the XY Mode!. I-Approach to Equilibrium
Dynamics of a Local Perturbation in the XY Mode!. I-Approach to Equilibrium D. B. Abraham§, E. Barouch∗§, G. Gallavotti and A. Martin-Löf Abstract: The magnetization and spin correlation functions of theX−Y model are analysed exactly when the system is subjected to a local perturbation of the magnetic field in the z-direction. When such a perturbation is removed, these quantities approach their...
متن کاملOff equilibrium dynamics in the 3d-XY system
We investigate through Monte Carlo simulations the non-equilibrium behaviour of the threedimensional XY-model quenched from a high temperature state to its ferromagnetic and critical phases. The two-times autocorrelation and response functions are determined in the asymptotic (scaling) regime, from which the nonequilibrium exponents λ and critical λ are extracted. The form of the scaling functi...
متن کاملBreakdown of scaling in the nonequilibrium critical dynamics of the two-dimensional XY model
The approach to equilibrium, from a nonequilibrium initial state, in a system at its critical point is usually described by a scaling theory with a single growing length scale, xi(t) approximately t(1/z), where z is the dynamic exponent that governs the equilibrium dynamics. We show that, for the 2D XY model, the rate of approach to equilibrium depends on the initial condition. In particular, x...
متن کاملar X iv : c on d - m at / 9 41 10 93 v 1 2 2 N ov 1 99 4 PHASE ORDERING OF 2 D XY SYSTEMS BELOW
We consider quenches in non-conserved two-dimensional XY systems between any two temperatures below the Kosterlitz-Thouless transition. The evolving systems are defect free at coarse-grained scales, and can be exactly treated. Correlations scale with a characteristic length L(t) ∝ t1/2 at late times. The autocorrelation decay exponent, λ̄ = (ηi + ηf )/2, depends on both the initial and the final...
متن کاملAdiabatic dynamics in a spin-1 chain with uniaxial single-spin anisotropy
We study the adiabatic quantum dynamics of an anisotropic spin-1 XY chain across a second order quantum phase transition. The system is driven out of equilibrium by performing a quench on the uniaxial single-spin anisotropy, that is supposed to vary linearly in time. We show that, for sufficiently large system sizes, the excess energy after the quench admits a non trivial scaling behavior that ...
متن کامل