Thermodynamic uncertainty relation in quantum thermoelectric junctions.
Thermodynamic uncertainty relation in quantum thermoelectric junctions.
复制标题
量子热电结中的热力学不确定性关系。
作者：
Junjie Liu;D. Segal
最近，为经典马尔可夫系统制定了热力学不确定性关系（TUR），证明了精度（电流波动）和成本（耗散）之间的权衡。违反 TUR 的系统很有趣，因为它们克服了另一种涉及热机效率、功率及其稳定性（功率波动）的权衡关系。在这里，我们分析了稳态下量子热电结中 TUR 违规的根源、程度及其对性能的影响。考虑到非相互作用电子，首先我们表明只有单电子转移事件产生的电流噪声的“经典”分量遵循 TUR。因此，电流噪声的剩余“量子”部分是导致此类量子系统中潜在违反 TUR 的原因。接下来，我们重点关注谐振传输机制，确定了可以观察到 TUR 违规的参数范围（对于电压偏置结和热电发动机）。我们通过串行双量子点系统的精确数值模拟来说明我们的发现。最重要的是，我们证明，当接近热力学效率极限时，TUR 在非相互作用热电发电机中始终成立。
Recently, a thermodynamic uncertainty relation (TUR) has been formulated for classical Markovian systems demonstrating trade-off between precision (current fluctuation) and cost (dissipation). Systems that violate the TUR are interesting as they overcome another trade-off relation concerning the efficiency of a heat engine, its power, and its stability (power fluctuations). Here, we analyze the root, extent, and impact on performance of TUR violations in quantum thermoelectric junctions at steady state. Considering noninteracting electrons, first we show that only the "classical" component of the current noise, arising from single-electron transfer events, follows the TUR. The remaining, "quantum" part of current noise is therefore responsible for the potential violation of the TUR in such quantum systems. Next, focusing on the resonant transport regime we determine the parameter range in which the violation of the TUR can be observed-for both voltage-biased junctions and thermoelectric engines. We illustrate our findings with exact numerical simulations of a serial double quantum dot system. Most significantly, we demonstrate that the TUR always holds in noninteracting thermoelectric generators when approaching the thermodynamic efficiency limit.