In addition to being a long-postulated particle that could explain the absence of the neutron’s dipole moment observed in laboratories—originating from the charge-parity problem in quantum chromodynamics—the axion emerges as a promising dark matter candidate due to its low mass and faint interaction with matter. Dark matter is a non-luminous substance believed to make up one-fifth of the known universe. If the axion constitutes dark matter, haloscopes—magnetized detectors that convert axions into microwaves—are by far the most promising experimental approach for their first direct detection.

The Dark photons & Axion-Like particles Interferometer (DALI) proposes a new experimental setup to detect wavy dark matters: the magnetized phased-array (MPA). In the MPA haloscope, a large flat mirror acting as a focal plane is housed in an ordinary solenoid-type superconducting magnet. A narrow-band signal originates from virialized axions that are converted into photons via the inverse Primakoff effect (or through kinetic mixing of paraphotons, another interesting dark matter candidate). The signal from each individual antenna forming the MPA is combined in a post-processing that is carried out to correct from phase mismatch and other differences between channels and systematics by means of radio interferometry -like methods. A series of microwave resonators, from various metamaterials to open cavities, can be also magnetized in the optical path to enhance the faint induced signal, for which we suggest/construct a tunable multilayer Fabry-Pérot resonator that allows for signal power enhancement factors in excess of 50,000 at the high band of the experimental range, say, 25-250 microelectronvolt (6-60 GHz), eventually broader. In this manner, DALI will reach sensitivity to benchmark dark matter candidates in a sector non-accessible to previous haloscopes. 

DALI's sensitivity to high-frequency gravitational waves arises from its mechanism of converting gravitons into photons. The search for ultra-high-frequency gravitational waves is a peripheral goal of the project, motivated by cosmological objectives. This research aims to provide insights into early universe processes, thereby offering valuable information about the conditions and dynamics of the universe at its very beginnings.

DALI, currently in the design and prototyping phase, is planned to be installed at the Teide Observatory within a protected environment against spurious microwave sources, known as CMBlab.