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arXiv 1712.04331hep-th
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高阶修正全息超导体的全息电导率

Holographic conductivity of holographic superconductors with higher order corrections

Ahmad Sheykhi, Afsoon Ghazanfari, Amin Dehyadegari

摘要:

本文用解析和数值方法研究了重力场和规范场的高阶修正项对$s$波全息超导体性质的影响。在引力场方面,我们考虑了高曲率的高斯-博内修正;在规范场方面,我们在麦克斯韦拉格朗日量中加入了二次修正项。我们表明,对于这个系统,人们仍然可以得到的临界温度和电荷密度之间的解析关系。我们还计算了临界指数和凝聚值的解析和数值。我们使用变分方法,基于Sturm-Liouville特征值问题的分析研究,以及数值射击方法,以便与我们的分析结果进行比较。在高斯-邦纳参数一定的情况下,我们观察到规范场的非线性度越大,临界温度越低。这意味着麦克斯韦电动力学的非线性修正项使凝聚更难。我们还研究了系统的全息电导率,揭示了Gauss-Bonnet和非线性参数$α$和$b$对超导能隙的影响。我们观察到,对于$α$和$b$的各种值,电导率的实部与频率/温度$ω/T$成比例,因为频率足够大。此外,电导率在虚部有一个极小值,随着温度的降低,该极小值向高频方向移动。

英文摘要:

We analytically as well as numerically disclose the effects of the higher order correction terms in the gravity and in the gauge field on the properties of $s$-wave holographic superconductors. On the gravity side, we consider the higher curvature Gauss-Bonnet corrections and on the gauge field side, we add a quadratic correction term to the Maxwell Lagrangian. We show that for this system, one can still obtain an analytical relation between the critical temperature and the charge density. We also calculate the critical exponent and the condensation value both analytically and numerically. We use a variational method, based on the Sturm-Liouville eigenvalue problem for our analytical study, as well as a numerical shooting method in order to compare with our analytical results. For a fixed value of the Gauss-Bonnet parameter, we observe that the critical temperature decreases with increasing the nonlinearity of the gauge field. This implies that the nonlinear correction term to the Maxwell electrodynamics make the condensation harder. We also study the holographic conductivity of the system and disclose the effects of Gauss-Bonnet and nonlinear parameters $α$ and $b$ on the superconducting gap. We observe that for various values of $α$ and $b$, the real part of conductivity is proportional to the frequency per temperature, $ω/T$, as frequency is enough large. Besides, the conductivity has a minimum in the imaginary part which is shifted toward greater frequency with decreasing the temperature.

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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