2 research outputs found
Tunable Wire Metamaterials for an Axion Haloscope
Metamaterials based on regular two-dimensional arrays of thin wires have
attracted renewed attention in light of a recently proposed strategy to search
for dark matter axions. When placed in the external magnetic field, such
metamaterials facilitate resonant conversion of axions into plasmons near their
plasma frequency. Since the axion mass is not known a priori, a practical way
to tune the plasma frequency of metamaterial is required. In this work, we have
studied a system of two interpenetrating rectangular wire lattices where their
relative position is varied. The plasma frequency as a function of their
relative position in two dimensions has been mapped out experimentally, and
compared with both a semi-analytic theory of wire-array metamaterials and
numerical simulations. Theory and simulation yield essentially identical
results, which in turn are in excellent agreement with experimental data. Over
the range of translations studied, the plasma frequency can be tuned over a
range of 16%
Searching For Dark Matter with Plasma Haloscopes
We summarise the recent progress of the Axion Longitudinal Plasma HAloscope
(ALPHA) Consortium, a new experimental collaboration to build a plasma
haloscope to search for axions and dark photons. The plasma haloscope is a
novel method for the detection of the resonant conversion of light dark matter
to photons. ALPHA will be sensitive to QCD axions over almost a decade of
parameter space, potentially discovering dark matter and resolving the Strong
CP problem. Unlike traditional cavity haloscopes, which are generally limited
in volume by the Compton wavelength of the dark matter, plasma haloscopes use a
wire metamaterial to create a tuneable artificial plasma frequency, decoupling
the wavelength of light from the Compton wavelength and allowing for much
stronger signals. We develop the theoretical foundations of plasma haloscopes
and discuss recent experimental progress. Finally, we outline a baseline design
for ALPHA and show that a full-scale experiment could discover QCD axions over
almost a decade of parameter space.Comment: Endorsers: Jens Dilling, Michael Febbraro, Stefan Knirck, and Claire
Marvinney. 26 pages, 17 figures, version accepted in Physical Review