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Abstract: We study the out-of-equilibrium dynamics of the fully-frustrated XY model. Atequilibrium, this model undergoes two phase transitions at two very closetemperatures: a Kosterlitz-Thouless topological transition and a second-orderphase transition between a paramagnetic phase and a low-temperature phase wherethe chiralities of the lattice plaquettes are anti-ferromagnetically ordered.We compute by Monte Carlo simulations two-time spin-spin andchirality-chirality autocorrelation and response functions. From the dynamicsof the spin waves in the low temperature phase, we extract thetemperature-dependent exponent $\eta$. We provide evidences for logarithmiccorrections above the Kosterlitz-Thouless temperature and interpret them as amanifestation of free topological defects. Our estimates of the autocorrelationexponent and the fluctuation-dissipation ratio differ from the XY values, while$\etaT { m KT}$ lies at the boundary of the error bar. Indications forlogarithmic corrections at the second-order critical temperature are presented.However, the coupling between angles and chiralities is still strong andexplains why autocorrelation exponent and fluctuation-dissipation ratio are farfrom the Ising values and seems stable.



Autor: Jean-Charles Walter IJL, Christophe Chatelain IJL

Fuente: https://arxiv.org/







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