Quantum phase transitions in the discrete phi(4) model: The crossover between two types of transitionстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 12 ноября 2012 г.
Аннотация:Quantum phase transitions in the discrete phi (4) model are studied in two dimensions (2D) and 3D at T = 0. Scenario of the transition can be changed continuously from the soft mode to transverse-field Ising case by the varying of a model parameter. This change is studied by the quantum Monte Carlo (QMC) simulation. To describe the numerical result, we use an extension of the mean-field scheme that takes nonlinearity of the on-site response into account. It reproduces QMC data with a 5% accuracy and becomes exact in the soft-mode limit. For the transverse-field Ising model, it gives the value of critical coupling with a 3% accuracy.