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arXiv 1401.0680quant-phcond-mat.quant-gas
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玻色-哈伯德模型临界指数的微扰计算

Perturbative calculation of critical exponents for the Bose-Hubbard model

Dennis Hinrichs, Axel Pelster, Martin Holthaus

摘要:

我们发展了一种计算玻色-哈伯德模型所示的莫特绝缘体-超流转变的临界指数的策略。我们的方法是基于场论的有效势的概念,它提供了一个自然的扩展的朗道理论的相变量子临界现象。用高阶微扰理论得到了该有效势的朗道展开式的系数。我们抵消了发散的弱耦合微扰级数包括很少考虑朗道系数$a_6$到我们的分析。我们的初步结果表明,凝聚体密度和超流密度的临界指数,来自二维玻色-哈伯德模型,偏离小于$1\%$从最知名的估计计算到目前为止的三维$XY$普适类。

英文摘要:

We develop a strategy for calculating critical exponents for the Mott insulator-to-superfluid transition shown by the Bose-Hubbard model. Our approach is based on the field-theoretic concept of the effective potential, which provides a natural extension of the Landau theory of phase transitions to quantum critical phenomena. The coefficients of the Landau expansion of that effective potential are obtained by high-order perturbation theory. We counteract the divergency of the weak-coupling perturbation series by including the seldom considered Landau coefficient $a_6$ into our analysis. Our preliminary results indicate that the critical exponents for both the condensate density and the superfluid density, as derived from the two-dimensional Bose-Hubbard model, deviate by less than $1\%$ from the best known estimates computed so far for the three-dimensional $XY$ universality class.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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