Simulações entrópicas do modelo de Ashkin-Teller
Nenhuma Miniatura disponível
Data
2016-03-10
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Goiás
Resumo
In 1943, Ashkin and Teller (AT) proposed a model to describe the behavior of a
system composed by four components that interact with each other. However the problem
has not been solved analytically for all parameters due to the complexity of the model.
Only thirty years later Fan (1972) proposed a change in order to analyze the system.
He made an analogy with the Ising model and described the interactions between the
components in terms of spins, leading to a simple matching with the Ising and Potts
q = 4 models and, enabling therefore a clearer comprehension of the model and allowing
the implementation of various techniques to investigate the behavior of the system with
the temperature. In 2001 Wang and Landau developed a Monte Carlo algorithm that
estimates directly the density of states and can be applied in the study of phase transitions
and the thermodynamic properties. This algorithm is based on a random walk in the space
of energies that leads to an estimate for the density of states. During the simulations an
energy histogram monitors the evolution of the density of states: whenever the flatness
criterion is satisfied, we obtain a finer level of the density of states. In this work we perform
a study of the Ashkin-Teller model using the Wang-Landau algorithm, determining the
behavior of the magnetization and the specific heat and estimating the critical exponents
, and
and the critical temperature through the finite-size theory for different values
of the model parameters.
Descrição
Palavras-chave
Citação
FERREIRA, L. S. Simulações entrópicas do modelo de Ashkin-Teller. 2016. 46 f. Dissertação (Mestrado em Fisica) - Universidade Federal de Goiás,Goiânia, 2016.