Quantum Sensing for High Frequency Gravitational Waves and Axion Dark Matter

by Claudio Gatti (INFN)

Tuesday 4 Mar 2025, 14:00 → 16:00 Europe/Madrid

IFAE Seminar Room (IFAE Main Building C7b)

Abstract

Microwave cavities in strong magnetic fields are among the most promising tools for detecting dark-matter axions and high-frequency gravitational waves. These searches rely on the Primakoff and Gertsenshtein effects, which predict the conversion of axions and gravitational waves, respectively, into electromagnetic radiation in the presence of a strong static magnetic field. In a microwave cavity, this interaction leads to the displacement of the vacuum state of the resonant mode, generating a coherent electromagnetic signal. Given the expected signal weakness, developing detectors with sensitivity beyond the quantum limit is crucial. In the C and X bands of the electromagnetic spectrum, superconducting qubits have demonstrated exceptional performance for this purpose. However, strong magnetic fields pose challenges, requiring either signal transport to a shielded region or the use of magnetically resilient devices. Additionally, qubit state readout errors due to noise and dephasing limit sensitivity. These challenges can be mitigated through quantum non-demolition measurements, either by repeating the measurement over time or employing multiple qubits simultaneously.

During the seminar, we will discuss ongoing developments at the COLD laboratory of the INFN Frascati National Laboratories, focusing on non-demolitive measurement techniques and the development of magnetically resilient qubits.

Dr. Claudio Gatti

Claudio Gatti obtained his degree in Physics at Rome University “La Sapienza” and the Ph.D. in Physics at Pisa University in 2003. He is Research Director at Laboratori Nazionali di Frascati (LNF) of INFN the Italian Institute of Nuclear Physics. His background is in experimental Particle Physics and collaborated with the KLOE and ATLAS experiments. He is the Coordinator of FLASH and of QUAX@LNF, two INFN funded experiments searching for galactic axions at LNF. He coordinates the activities of COLD (http://coldlab.lnf.infn.it) the cryogenic laboratory for detectors at LNF where several R&D projects on superconductive cavities and quantum sensors are ongoing, including ICSC and NQSTI, two projects funded by the EU Recovery Plan (PNRR) whose objective, among others, is the development of technologies based on superconducting qubits. The COLD team is now composed of about 15 people including Post Docs, technicians and master students.

In 2024, Claudio Gatti received the ERC Synergy Grant with M. Schott, D. Budker and D. Blas for the project GravNet a global network for the search for high-frequency gravitational waves