Isaac Newton Institute for Mathematical Sciences, University of Cambridge, 20 Clarkson Road, Cambridge CB3 0EH, United Kingdom and School of Mathematical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom.
Phys Rev Lett. 2013 Dec 6;111(23):231801. doi: 10.1103/PhysRevLett.111.231801. Epub 2013 Dec 2.
We provide theoretical arguments that dark-matter axions from the galactic halo that pass through Earth may generate a small observable signal in resonant S/N/S Josephson junctions. The corresponding interaction process is based on the uniqueness of the gauge-invariant axion Josephson phase angle modulo 2π and is predicted to produce a small Shapiro steplike feature without externally applied microwave radiation when the Josephson frequency resonates with the axion mass. A resonance signal of so far unknown origin observed by C. Hoffmann et al. [Phys. Rev. B 70, 180503(R) (2004)] is consistent with our theory and can be interpreted in terms of an axion mass m(a)c2=0.11 meV and a local galactic axionic dark-matter density of 0.05 GeV/cm3. We discuss future experimental checks to confirm the dark-matter nature of the observed signal.
我们提供了理论论据，即穿过地球的银河系晕中的暗物质轴子可能会在共振 S/N/S 约瑟夫森结中产生可观测到的小信号。相应的相互作用过程基于规范不变的轴子约瑟夫森相位角除以 2π 的独特性，并且当约瑟夫森频率与轴子质量共振时，无需外部微波辐射即可预测产生小的 Shapiro 阶跃特征。C. Hoffmann 等人观察到的到目前为止未知来源的共振信号与我们的理论一致，可以用轴子质量 m(a)c2=0.11 meV 和局部银河轴子暗物质密度 0.05 GeV/cm3 来解释。我们讨论了未来的实验检验来确认观察到的信号的暗物质性质。
