Axion quasiparticles for axion dark matter detection

Abstract

It has been suggested that certain antiferromagnetic topological insulators contain axion quasiparticles (AQs), and that such materials could be used to detect axion dark matter (DM). The AQ is a longitudinal antiferromagnetic spin fluctuation coupled to the electromagnetic Chern-Simons term, which, in the presence of an applied magnetic field, leads to mass mixing between the AQ and the electric field. The electromagnetic boundary conditions and transmission and reflection coefficients are computed. A model for including losses into this system is presented, and the resulting linewidth is computed. It is shown how transmission spectroscopy can be used to measure the resonant frequencies and damping coefficients of the material, and demonstrate conclusively the existence of the AQ. The dispersion relation and boundary conditions permit resonant conversion of axion DM into THz photons in a material volume that is independent of the resonant frequency, which is tuneable via an applied magnetic field. A parameter study for axion DM detection is performed, computing boost amplitudes and bandwidths using realistic material properties including loss. The proposal could allow for detection of axion DM in the mass range between 1 and 10 meV using current and near future technology.

Axion dark matter: How to see it?

“…The independence of sample volume of the resonance allows for high sensitivity at high frequencies with broad tunability provided by varying the external magnetic field. A recent proposal called TOORAD (TOpolOgical Resonant Axion Detection) has developed the theory of axion quasiparticles in topological magnetic insulators and characterized a realistic experimental setup with an antiferromagnetic insulator (Fe-doped Bi 2 Se 3 or Mn 2 Bi 2 Te 5 ) to realize these axion quasiparticles assuming a wide bandwidth single-photon detector highly efficient in terahertz ( 76 ). Besides, there are many other interesting ideas that have been put forth recently for axion detection in condensed matter systems ( 77 , 78 ).…”

Radio line properties of axion dark matter conversion in neutron stars

“…One particularly useful aspect of radio detection of axion dark matter in NSs is that it has the potential to guide and complement existing haloscope experiments. Notable proposed and ongoing examples are MADMAX [42,43], HAYSTAC [44], ADMX [45], ORGAN [46] as well as many other proposed experiments involving novel condensed matter and metamaterial structures [47][48][49].…”

Direct Observation of Antiferromagnetic Parity Violation in the Electronic Structure of Mn$_2$Au

“…Although similar information could in principle be obtained by the second-harmonic generation [32], this Néel vector imaging technique has proven very challenging in metallic systems, being most successful in insulating magnetoelectric materials. The method is viable in principle in many antiferromagnets described by one of the 21 PT symmetric magnetic point groups, which account for a large fraction (17%) of all magnetic point groups [33].…”