Title: Tunable Thermoelectric Superconducting Heat Pipe and Diode

Abstract: Efficient heat management at cryogenic temperatures is crucial for superconducting quantum technologies. In this study, we demonstrate the heat diode performance of a gap asymmetric superconducting tunnel junction. Our results show that the mechanism of bipolar thermoelectricity, which occurs when the hot side has the larger gap, boosts heat rectification. This improvement is consistent for a broad range of thermal biases and for different values of the superconducting gaps. Additionally, we demonstrate that bipolar thermoelectricity can act as a heat pipe, reducing heat losses towards cold terminals and increasing overall efficiency up to $65\%$. Finally, we show that by adjusting the electrical load, it is possible to tune the heat pipe and diode performances.