Phase fluctuations in superconductors: From Galilean invariant to quantum XY models
Phase fluctuations in superconductors: From Galilean invariant to quantum XY models
复制标题
超导体中的相位涨落：从伽利略不变量到量子 XY 模型
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
C. Castellani
中科院分区：
文献类型：
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作者：
L. Benfatto;A. Toschi;S. Caprara;C. Castellani
我们分析了修正超流密度由于相位波动内的连续和晶格模型的s-和d-波超导体。我们扩展的相位只有行动超出高斯水平，并比较我们的结果与量子mathrm{XY}$模型在量子和经典制度。我们发现动态的非谐顶点，缺席的量子$mathrm{XY}$模型，这是负责在零温度下的连续（伽利略不变量）模型的超流密度的校正消失。此外，相位波动效应相对于$mathrm{XY}$模型至少减少了${1/（k}_{F}{ensuremath{xi}}_{0}{）}^{2}阶的因子。$
We analyze the corrections to the superfluid density due to phase fluctuations within both a continuum and a lattice model for s- and d-wave superconductors. We expand the phase-only action beyond the Gaussian level and compare our results with the quantum $mathrm{XY}$ model both in the quantum and in the classical regime. We find dynamic anharmonic vertices, absent in the quantum $mathrm{XY}$ model, which are responsible for the vanishing of the correction to the superfluid density at zero temperature in a continuum (Galilean invariant) model. Moreover, the phase-fluctuation effects are reduced with respect to the $mathrm{XY}$ model by a factor at least of order ${1/(k}_{F}{ensuremath{xi}}_{0}{)}^{2}.$