论文标题
弱耦合极限中的Eliashberg理论的热力学
Thermodynamics of Eliashberg theory in the weak-coupling limit
论文作者
论文摘要
在Eliashberg理论中计算出的间隙和临界温度的弱耦合极限令人惊讶地偏离BCS理论预测的$ 1/\ sqrt {e} $。然而，有趣的是，这两个数量的比率都同意这两种理论。在此结果的推动下，我们在这里研究了Eliashberg理论的弱耦合热力学，并以自由能，特定热量和临界磁场的重点重点。特别是，我们从数值上计算超导和正常状态的特定热量之间的差异，我们发现该数量与其BCS的差异不同，而在$ t_ {c} $下方的所有温度下，该数量的差异为$ 1/\ sqrt {e} $。我们发现，特异性不连续性与正常状态比热的无量纲比率减少到由$ΔC_{V}给出的BCS预测（t_ {c}）/c_ {v，n}（t_c）（t_c）\ lot1.43 $。这进一步证明了所有无量纲比率在弱耦合极限下趋向于其“普遍价值”的期望。
The weak-coupling limits of the gap and critical temperature computed within Eliashberg theory surprisingly deviate from the BCS theory predictions by a factor of $1/\sqrt{e}$. Interestingly, however, the ratio of these two quantities agrees for both theories. Motivated by this result, here we investigate the weak-coupling thermodynamics of Eliashberg theory, with a central focus on the free energy, specific heat, and the critical magnetic field. In particular, we numerically calculate the difference between the superconducting and normal-state specific heats, and we find that this quantity differs from its BCS counterpart by a factor of $1/\sqrt{e}$, for all temperatures below $T_{c}$. We find that the dimensionless ratio of the specific-heat discontinuity to the normal-state specific heat reduces to the BCS prediction given by $ΔC_{V}(T_{c})/C_{V,n}(T_c)\approx1.43$. This gives further evidence to the expectation that all dimensionless ratios tend to their "universal values" in the weak-coupling limit.
