Low-Temperature Properties of Ising Antiferromagnet on a Stacked Triangular Lattice

An Ising antiferromagnet on a stacked triangular lattice in zero field is studied by Monte Carlo simulations, focusing on the character of the low-temperature phase and the effect of the relative strength of the exchange interaction in the stacking direction α. Our results support the presence of the 3D Wannier phase, with the sublattice magnetization structure (m, -m, 0) and power-law decaying m with the lattice size. The extent of this low-temperature phase shrinks with decreasing α, however, it appears even at very low values if it is accessed from higher temperatures by sufficiently slow cooling

Percolation process in the presence of velocity fluctuations: One-loop approximation

Critical behaviour of directed bond percolation is studied in presence of an advective velocity field. The velocity field is assumed to be incompressible and generated by the Kraichnan model. The model is studied by means of fieldtheoretic approach. The renormalization group (RG) method is used in order to analyse asymptotic large-scale behaviour of the model near its critical point and to calculate perturbatively all fixed RG points and critical exponents in the framework of double-expansion scheme [1]. We classify possible asymptotic regimes corresponding to infrared stable fixed points of the RG equations which have been calculated up to the one-loop approximation

Directed bond percolation process: Calculation of critical exponents in three-loop approximation

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