Numerical investigation of the ageing of the fully frustrated XY model

作者：Walter J C^*; Chatelain C

来源：Journal of Statistical Mechanics: Theory and Experiment , 2009, 2009(10): P10017.

DOI：10.1088/1742-5468/2009/10/P10017

• classical Monte Carlo simulations
• critical exponents and amplitudes (theory)
• slow dynamics and ageing (theory)

We study the out-of-equilibrium dynamics of the fully frustrated XY model. At equilibrium, this model undergoes two phase transitions at two very close temperatures: a Kosterlitz-Thouless topological transition and a second-order phase transition between a paramagnetic phase and a low-temperature phase where the chiralities of the lattice plaquettes are antiferromagnetically ordered. We compute by means of Monte Carlo simulations two-time spin spin and chirality-chirality autocorrelation and response functions. From the dynamics of the spin waves in the low-temperature phase, we extract the temperature-dependent exponent.. We provide evidence for logarithmic corrections above the Kosterlitz-Thouless temperature and interpret them as a manifestation of free topological defects. Our estimates of the autocorrelation exponent and the fluctuation-dissipation ratio differ from the XY values, while.(TKT) lies at the boundary of the error bar. Indications for logarithmic corrections at the second-order critical temperature are presented. However, the coupling between angles and chiralities is still strong and explains why the autocorrelation exponent and fluctuation-dissipation ratio are far from the Ising values and seem stable.

• 出版日期2009-10