A Radio for Hidden-Photon Dark Matter Detection
  We propose a resonant electromagnetic detector to search for hidden-photon
dark matter over an extensive range of masses. Hidden-photon dark matter can be
described as a weakly coupled "hidden electric field," oscillating at a
frequency fixed by the mass, and able to penetrate any shielding. At low
frequencies (compared to the inverse size of the shielding), we find that
observable effect of the hidden photon inside any shielding is a real,
oscillating magnetic field. We outline experimental setups designed to search
for hidden-photon dark matter, using a tunable, resonant LC circuit designed to
couple to this magnetic field. Our "straw man" setups take into consideration
resonator design, readout architecture and noise estimates. At high
frequencies,there is an upper limit to the useful size of a single resonator
set by $1/\nu$. However, many resonators may be multiplexed within a
hidden-photon coherence length to increase the sensitivity in this regime.
Hidden-photon dark matter has an enormous range of possible frequencies, but
current experiments search only over a few narrow pieces of that range. We find
the potential sensitivity of our proposal is many orders of magnitude beyond
current limits over an extensive range of frequencies, from 100 Hz up to 700
GHz and potentially higher.
