12 research outputs found
Exploration of Wire Array Metamaterials for the Plasma Axion Haloscope
A plasma haloscope has recently been proposed as a feasible approach to
extend the search for dark matter axions above 10 GHz ( 40 eV),
whereby the microwave cavity in a conventional axion haloscope is supplanted by
a wire array metamaterial. As the plasma frequency of a metamaterial is
determined by its unit cell, and is thus a bulk property, a metamaterial
resonator of any frequency can be made arbitrarily large, in contrast to a
microwave cavity which incurs a steep penalty in volume with increasing
frequency. We have investigated the basic properties of wire array
metamaterials through measurements in the 10 GHz range. Excellent
agreement with theoretical models is found, by which we project achievable
quality factors to be of order in an actual axion search. Furthermore,
schemes for tuning the array over a usable dynamic range ( in frequency)
appear practical from an engineering perspective.Comment: to be submitted to Physical Review Letters; typos correcte
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 summarize 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
DMRadio-m: A Search for the QCD Axion Below eV
The QCD axion is one of the most compelling candidates to explain the dark
matter abundance of the universe. With its extremely small mass (), axion dark matter interacts as a classical field rather
than a particle. Its coupling to photons leads to a modification of Maxwell's
equations that can be measured with extremely sensitive readout circuits.
DMRadio-m is a next-generation search for axion dark matter below
eV using a T static magnetic field, a coaxial inductive pickup, a
tunable LC resonator, and a DC-SQUID readout. It is designed to search for QCD
axion dark matter over the range (). The primary
science goal aims to achieve DFSZ sensitivity above neV (30
MHz), with a secondary science goal of probing KSVZ axions down to
(10 MHz).Comment: 8 pages, 4 figures. Updated to fix small errors and correct
acknowledgement
New Results from HAYSTAC's Phase II Operation with a Squeezed State Receiver
A search for dark matter axions with masses has been
performed using the HAYSTAC experiment's squeezed state receiver to achieve
sub-quantum limited noise. This report includes details of the design and
operation of the experiment previously used to search for axions in the mass
ranges and (GHz) and
GHz) as well as upgrades to facilitate an extended search at
higher masses. These upgrades include improvements to the data acquisition
routine which have reduced the effective dead time by a factor of 5, allowing
for the new region to be scanned 1.6 times faster with comparable
sensitivity. No statistically significant evidence of an axion signal is found
in the range (GHz), leading to an
aggregate upper limit exclusion at the level on the axion-photon
coupling of .Comment: 20 pages, 16 figure
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Proposal for a definitive search for GUT-scale QCD axions
The QCD axion is a leading dark matter candidate that emerges as part of the solution to the strong CP problem in the Standard Model. The coupling of the axion to photons is the most common experimental probe, but much parameter space remains unexplored. The coupling of the QCD axion to the Standard Model scales linearly with the axion mass; therefore, the highly motivated region 0.4-120 neV, corresponding to a GUT-scale axion, is particularly difficult to reach. This paper presents the design requirements for a definitive search for GUT-scale axions and reviews the technological advances needed to enable this program