Abstract
We study magnetic critical behavior in the two-dimensional Ashkin–Teller model with an asymmetric defect line. This system is represented by two Ising lattices of spins σ and τ interacting through a four-spin coupling ε. In addition, the couplings between σ-spins are modified along a particular line, whereas couplings between τ-spins are kept unaltered. This problem has been previously considered by means of analytical field-theoretical methods and by numerical techniques, with contradictory results. For ε>0 field-theoretical calculations give a magnetic critical exponent corresponding to σ-spins which depends on the defect strength only (it is independent of ε), while τ-spins magnetization decay with the universal Ising value 1/8. On the contrary, numerical computations based on density matrix renormalization (DMRG) give, for ε>0 similar scaling behaviors for σ and τ spins, which depend on both ε and defect intensity. In this paper we revisit the problem by performing a direct Monte Carlo simulation. Our results are in good agreement with DMRG computations. By reexamining the field-theoretical approach, we show how numerical and analytical results can be reconciled when a more general regularization prescription is adopted.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Physica A: Statistical Mechanics and its Applications
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
