Speaker
Description
The QUAX experiment is committed in the search of light dark matter candidates, such as axions and axion-like particles, with a haloscope setup involving microwave resonant cavities. Many avenues to push further the haloscope sensitivity are being tested, facing some technological challenges. One of these is the development of superconducting cavities and dielectric cavities, showing unprecedented quality factors in magnetic fields. Then, haloscopes require ultra-low-noise amplification: for this purpose, we are developing i) a custom Josephson Parametric Amplifier (JPA) as a preamplification stage at cryogenic temperature giving noise at the Standard Quantum Limit (SQL); ii) a Travelling Wave JPA (TWJPA), giving a large bandwidth amplification ($\sim 5$ GHz) near the SQL; iii) a single microwave photon detector (SPD) exploiting Josephson junctions.
Here I present the latest advances in the measurements of dielectric cavities made of sapphire shells, and superconducting cavities, such as YBCO and Nb$_3$Sn, the latter having very promising values of quality factor, of the order of $2.5\times 10^5$ at 9 T. I also present the status of the art on the design and characterization of the first prototypes of JPA, TWJPA and SPD.
Moreover I present the first qubit characterization in the COLD laboratory at LNF, opening the route to the possibility of coupling the qubit to a haloscope to perform quantum non-demolition detection of single microwave photons for axion searches.
