Amplification of electromagnetic waves by a rotating body

这是一项蓝天研究提案，旨在为基础物理学中一项50年来的预测提供第一个实验证据：在与旋转的金属或吸收球体的相互作用中放大电磁波。首先，证明这一效应的重要性在于，机械旋转可以导致负频率的产生这一基本物理概念。这些负频率的存在导致了从吸收到增益的转变，从而放大了反射波。这一预测最早是由泽尔多维奇在1971年提出的，它与罗杰·彭罗斯在1969年提出的可能从旋转的黑洞中提取能量的提议密切相关。泽尔多维奇关于电磁波的想法从未得到实验验证，因为在实现放大条件方面显然不可能有技术障碍：机械物体的旋转速度需要快于电磁波的振荡频率。在过去的12个月里，研究人员取得了一项突破性的发现，通过将逝去场耦合到吸收物体上来解决了这一技术问题。这一概念在理论上和实验上都得到了声波的验证，并在理论上推广到超导电路中的电磁波。展望未来，我们的目标是实现实验，展示超导电路模式的放大，这种模式封闭并逐渐耦合到以MHz频率旋转的悬浮金属微球。我们还将研究如何实现这一点将为观察量子电磁涨落的放大和检测铺平道路，从而潜在地为超导电路中的单光子相互作用提供新的和令人兴奋的途径。

This is a blue-sky research proposal that aims to provide the first experimental evidence of a 50-year-old prediction in fundamental physics: the amplification of electromagnetic (EM) waves in the interaction with a rotating metallic or absorbing sphere. The importance of demonstrating this effect lies, in a first instance, in the underlying physical concept that mechanical rotation can induce the creation of negative frequencies. The presence of these negative frequencies is what causes the transition from absorption to gain and hence amplification of reflected waves. This prediction was first made by Zel'dovich in 1971 and is tightly connected to Roger Penrose's proposal in 1969 that it might be possible to extract energy from a rotating black hole. Zel'dovich's idea involving EM waves, has never been verified experimentally due to the apparently impossible technological barrier in realizing the amplification condition: the mechanical object rotation rates need to be faster than the oscillation frequency of the EM wave. The investigators have made a breakthrough discovery in the past 12 months that resolves the technological issue by resorting to evanescent field coupling to the absorbing object. This concept has been theoretically and experimentally verified with sound waves and theoretically extended to EM waves in a superconducting circuit. Looking forward, we aim to implement experiments that will show amplification of superconducting circuit modes that enclose and are evanescently coupled to a levitated metallic microsphere rotating at MHz frequencies. We will also study how achieving this will pave the way to observing the amplification and detection of quantum EM fluctuations, thus potentially providing new and exciting routes towards single photon interactions in superconducting circuits.