Quantum discrete phi(4) model at finite temperaturesстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 12 ноября 2012 г.
Аннотация:Quantum phase transitions are studied in the framework of the quantum discrete phi(4) model at zero and finite temperatures by quantum Monte Carlo calculations and the simplest analytical approximations. Parameters of the model (mass m, temperature t, and dimensionless parameter a) allow us to go continuously from quantum (t=0) to classical (m–>+infinity) phase transitions and from displacive (a–>+0) to order-disorder (a–>+infinity) ones. Phase diagrams (dependencies of the critical mass on the critical temperature) are obtained for two- and three-dimensional systems for various values of the parameter a. The quantum Monte Carlo results show excellent agreement with previous studies of the discrete phi(4) model in the various limits. The obtained quantum Monte Carlo data are compared with results of the mean-field and independent-mode approaches. The mean-field approximation is in qualitative agreement with quantum Monte Carlo results for a wide range of the parameter a of the model, while the independent-mode one is in quantitative agreement at small values of a. The obtained results can be used for estimations of the behavior of real ferroelectrics.