Basically, a Josephson junction consists of two superconducting materials separated by a thin layer of non-superconducting material. A superconductor is a material through which a current can flow without any resistance. Within a superconductor the electrons flowing through the material pair up (known as Cooper pairs). This pairing is an effect of quantum mechanics. If you have two superconductors separated by a thin layer of regular material, then the paired electrons can flow through the regular material at a constant rate, known as a supercurrent. This supercurrent is very sensitive to changes in voltage, so Josephson junctions are used in devices to make extremely sensitive measurements of voltage and magnetic fields. If dark matter is made of axions (and that’s still a big if) then there should be lots of them flowing through the Earth all the time. Some of them would also interact with Josephson junctions, and that interaction should be observable as a fluctuation in the supercurrent. The hard part will be to make sure that the junctions are shielded from other interference, such as radio and microwave radiation, but that doesn’t seem to be an insurmountable problem.
It could be that there is a background of magnetic interference from cosmological LENR. This magnetic background could be the quantity that is being measured by the Josephson junction. If the Josephson junction is perfectly shielded by magnetic interference of all types and the effect is still present then there may be a particle involved. But if the Josephson junction stops its fluctuations, then magnetic interference might be involved. On Tue, Aug 5, 2014 at 3:19 PM, Jones Beene <[email protected]> wrote: > *From:* Ron Kita > > > > In the Wired article is a comment by Cathar Seamus...on a possible dark > matter interaction at 100 Ghz. > > > > Here is the comment. Note that 100 GHz is in the W band, which is reserved > by the military and NASA… just sayin’… > > > > “I believe that they might be hitting a dark matter resonance: microwave > photons have approx. 10^-23 Joules = 10^-4 eV. Josephson-Junctions > experiments discovered an axionic dark matter resonance at.. 0.11 meV. This > cavity is tuned to 10^-25 Joule photons, if this connection I suspect is > correct, the maximum thrust should occur at 100 GHz frequencies” > > > http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.111.231801 > > > > *Abstract * > > 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 mac2=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. > > > > >
