DARKLESS: Exploring axion dark matter and gravitational waves with a scalable experimental platform

Objective

DARKLESS is a research project aiming to shed light on two of the most profound open questions in fundamental physics: the nature of dark matter (DM) and the existence of high-frequency gravitational waves (GWs). Hosted at the Instituto de Astrofísica de Canarias (IAC) under the supervision of Prof. Rafael Rebolo—a world-leading expert in microwave instrumentation and its application to cosmology—DARKLESS will use a newly built detector prototype, DALI(PoP), to search for axions—hypothetical particles that may constitute DM—and GW signals in the 6–8 GHz range. The detector will operate with sensitivity nearly an order of magnitude beyond the current state of the art in both fields, enabling identification of candidate spectral signals or setting new exclusion limits on theoretical models and cosmological simulations. It will translate the Fellow’s step-by-step programme—from concept to prototype—into practice via the first scientific exploitation of DALI(PoP). In parallel, the project will develop and test scalable methods for coherent multichannel signal combination, informing the design and validating performance for the future full DALI, a next-generation experiment with enhanced discovery reach. This work builds on the IAC’s expertise in microwave cosmology and radio interferometry and constitutes a two-way knowledge exchange that advances the Fellow’s path to research independence—developing state-of-the-art instrumentation, quantitative analysis, theoretical insight and open-science leadership—while extending the Host’s capabilities at the frontier of fundamental physics. The action also benefits from targeted knowledge transfer with world-leading international GW consortia and laboratories. DARKLESS will foster international mobility, reinforce Europe’s leadership in astroparticle instrumentation, and deliver a timely, ambitious, and original contribution to the European Research Area.