We propose a new broadband search strategy for ultralight axion dark matter that interacts with electromagnetism. An oscillating field induces transitions between two quasi-degenerate resonant modes of superconducting cavity. In runs optimized high and low masses, this setup can probe unexplored parameter space axion-like particles covering fifteen orders magnitude in mass, including astrophysi...

Abstract Ultralight bosons can be abundantly produced through superradiance process by a spinning black hole and form bound state with hydrogen-like spectrum. We show that such gravitational atom typically possesses anomalously large mass quadrupole leads to significant orbital precession when it forms an eccentric binary second compact object. Dynamically formed binaries or pulsar-black are du...

The polarization of Cosmic Microwave Background (CMB) photons is rotated as they pass through (ultralight-) axion string loops. Studying this birefringence can reveal valuable information about the axion-photon coupling and structure network. We develop an approximate analytic formalism identify a kernel function that be used to calculate two-point correlation for CMB induced by arbitrary Using...