Katayama Haruna
Graduate School of Advanced Science and Engineering, Hiroshima University, Higashihiroshima, 739-8521, Japan.
Sci Rep. 2021 Sep 27;11(1):19137. doi: 10.1038/s41598-021-98456-0.
A black hole laser in analogues of gravity amplifies Hawking radiation, which is unlikely to be measured in real black holes, and makes it observable. There have been proposals to realize such black hole lasers in various systems. However, no progress has been made in electric circuits for a long time, despite their many advantages such as high-precision electromagnetic wave detection. Here we propose a black hole laser in Josephson transmission lines incorporating metamaterial elements capable of producing Hawking-pair propagation modes and a Kerr nonlinearity due to the Josephson nonlinear inductance. A single dark soliton obeying the nonlinear Schrödinger equation produces a black hole-white hole horizon pair that acts as a laser cavity through a change in the refractive index due to the Kerr effect. We show that the resulting laser is a squeezed-state laser characterized by squeezing parameters. We also evaluate the degree of quantum correlation between Hawking and its partner radiations using entanglement entropy which does not require simultaneous measurements between them. As a result, the obtained entanglement entropy depending on the soliton velocity provides strong evidence that the resulting laser is derived from Hawking radiation with quantum correlation generated by pair production from the vacuum.
引力模拟中的黑洞激光器放大了霍金辐射（这种辐射在真实黑洞中不太可能被测量到）并使其可被观测到。已经有在各种系统中实现这种黑洞激光器的提议。然而，尽管电路有诸如高精度电磁波检测等诸多优点，但长期以来在电路方面却没有取得进展。在此，我们提出一种基于约瑟夫森传输线的黑洞激光器，该传输线包含能够产生霍金对传播模式以及因约瑟夫森非线性电感而产生克尔非线性的超材料元件。一个遵循非线性薛定谔方程的单个暗孤子会产生一个黑洞 - 白洞视界对，该对通过克尔效应引起的折射率变化充当激光腔。我们表明，由此产生的激光器是一种具有压缩参数特征的压缩态激光器。我们还使用纠缠熵评估霍金辐射与其伴生辐射之间的量子关联程度，这并不需要对它们进行同时测量。结果，所获得的取决于孤子速度的纠缠熵提供了有力证据，表明由此产生的激光器源自具有通过真空对产生所产生的量子关联的霍金辐射。
