论文标题
离散的时间翻译对称性在约瑟夫森连接激光器
Discrete time translation symmetry breaking in a Josephson junction laser
论文作者
论文摘要
当微波腔是由电压偏置的约瑟夫森交界处驱动时，就会实现约瑟夫森连接激光。通过AC Josephson效应，直流电压会产生一个周期性驱动器，该驱动器作用于腔内并在其模式之间产生相互作用。一个足够强的驱动器能够在空腔基本频率下将驱动器高转换为光子的驱动谐振，从而打破了约瑟夫森频率设置的离散时间翻译对称性。使用经典模型，我们确定该转变何时以及如何随偏置电压的函数和腔模式的数量发生。我们发现，模式数和电压的某些组合倾向于促进通过模式子集中不稳定性出现的过渡。尽管系统的复杂性，但在某些情况下可以通过分析获得临界驱动强度。
A Josephson junction laser is realised when a microwave cavity is driven by a voltage-biased Josephson junction. Through the ac Josephson effect, a dc voltage generates a periodic drive that acts on the cavity and generates interactions between its modes. A sufficiently strong drive enables processes that down-convert a drive resonant with a high harmonic into photons at the cavity fundamental frequency, breaking the discrete time translation symmetry set by the Josephson frequency. Using a classical model, we determine when and how this transition occurs as a function of the bias voltage and the number of cavity modes. We find that certain combinations of mode number and voltage tend to facilitate the transition which emerges via an instability within a subset of the modes. Despite the complexity of the system, there are cases in which the critical drive strength can be obtained analytically.
