Hydrodynamic transport and violation of the viscosity-to-entropy ratio bound in nodal-line semimetals
Hydrodynamic transport and violation of the viscosity-to-entropy ratio bound in nodal-line semimetals
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DOI：
10.1103/physrevresearch.3.033003
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发表时间：
2020-09
影响因子：
4.2
通讯作者：
Sang Wook Kim;Geo Jose;B. Uchoa
中科院分区：
文献类型：
--
作者：
Sang Wook Kim;Geo Jose;B. Uchoa
剪切粘度和熵 η/s 之间的比率被认为是量子系统中相互作用强度的通用度量。据推测，该量具有通用下界 (1/4π)h̄/kB ，这表明存在非常强相关的量子流体。通过求解流体动力学状态下节线半金属的量子动力学理论，我们证明 η/s ∝ T 违反了通用下界，随着扰动极限内温度 T 的降低而趋向于零。我们发现，碰撞之间的流体动力学散射时间几乎与温度无关，直至对数标度校正，并且对于大节点线来说可能非常短，接近莫特-拉格尔-约夫极限。我们的发现表明，节点线半金属可以是非常强相关的量子系统。
The ratio between the shear viscosity and the entropy η/s is considered a universal measure of the strength of interactions in quantum systems. This quantity was conjectured to have a universal lower bound (1/4π)h̄/kB , which indicates a very strongly correlated quantum fluid. By solving the quantum kinetic theory for a nodal-line semimetal in the hydrodynamic regime, we show that η/s ∝ T violates the universal lower bound, scaling towards zero with decreasing temperature T in the perturbative limit. We find that the hydrodynamic scattering time between collisions is nearly temperature independent, up to logarithmic scaling corrections, and can be extremely short for large nodal lines, near the Mott-Ragel-Ioffe limit. Our finding suggests that nodal-line semimetals can be very strongly correlated quantum systems.