We investigate the noise current in a thermally biased tunnel junction between two superconductors with different zero-temperature gaps. When the Josephson effect is suppressed, this structure can support a nonlinear thermoelectric effect due to the spontaneous breaking of electron-hole symmetry, as we recently theoretically predicted. We discuss the possibly relevant role played by the noise in the junction. While a moderate noise contribution assists the generation of the thermoelectric signal, further unveiling the spontaneous nature of the electron-hole symmetry breaking, a large noise contribution can induce a switching between the two stationary thermoelectric values, thus hardening the detection of the effect and its application. We demonstrate that the thermoelectric effect is robust to the presence of noise for a wide range of parameters and that the spurious fluctuations of the thermoelectric signal can be lowered by increasing the capacitance of the junction, for instance by expanding the junction's size. Our results pave the way to the future experimental observation of the thermoelectric effect in superconducting junctions, and to improved performance in quantum circuits designed for thermal management.

中文翻译：

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约瑟夫森结非线性热电中的噪声效应

我们研究了具有不同零温度间隙的两个超导体之间的热偏置隧道结中的噪声电流。正如我们最近在理论上预测的那样，当约瑟夫森效应被抑制时，由于电子 - 空穴对称性的自发破坏，这种结构可以支持非线性热电效应。我们讨论了结中噪声所起的可能相关作用。虽然适度的噪声贡献有助于热电信号的产生，进一步揭示电子-空穴对称性破坏的自发性质，但大的噪声贡献可以引起两个固定热电值之间的切换，从而加强效应的检测及其应用。我们证明了热电效应对于各种参数的噪声是稳健的，并且可以通过增加结的电容来降低热电信号的虚假波动，例如通过扩大结的尺寸。我们的结果为未来对超导结中的热电效应进行实验观察铺平了道路，并改善了为热管理设计的量子电路的性能。