论文标题
统一费米气体中的量子临界热传输
Quantum critical thermal transport in the unitary Fermi gas
论文作者
论文摘要
密切相关的系统通常与在有限温度相图中控制其行为的潜在量子临界点有关。它们的热力学和运输特性来自关键波动，并遵循普遍的缩放定律。在这里，我们在量子和散射时间方面发展了一种量子临界状态的热传输的微观理论。我们明确计算量子临界模型系统中的特征缩放函数，即单一的费米气体。此外，我们得出了一个精确的热和热和能量电流的热和规则，并使用非扰动Luttinger-Ward方法进行数值评估。对于热散射时间，我们找到一种简单的量子临界缩放形式。总和规则和散射时间共同确定了从高温到量子临界机制的热导率，热扩散率，prandtl数量和声音扩散率。结果提供了对超速费米气体中最新声音衰减测量的定量描述。
Strongly correlated systems are often associated with an underlying quantum critical point which governs their behavior in the finite temperature phase diagram. Their thermodynamical and transport properties arise from critical fluctuations and follow universal scaling laws. Here, we develop a microscopic theory of thermal transport in the quantum critical regime expressed in terms of a thermal sum rule and an effective scattering time. We explicitly compute the characteristic scaling functions in a quantum critical model system, the unitary Fermi gas. Moreover, we derive an exact thermal sum rule for heat and energy currents and evaluate it numerically using the nonperturbative Luttinger-Ward approach. For the thermal scattering times we find a simple quantum critical scaling form. Together, the sum rule and the scattering time determine the heat conductivity, thermal diffusivity, Prandtl number and sound diffusivity from high temperatures down into the quantum critical regime. The results provide a quantitative description of recent sound attenuation measurements in ultracold Fermi gases.
