Demonstrating the thermal noise limit in a backaction-free bulk acoustic wave resonator chain for gravitational wave detection
Abstract
We report the full sub-Kelvin characterization of the BAUSCIA high-frequency gravitational-wave antenna, based on cryogenic Bulk Acoustic Wave resonators coupled to SQUID amplifiers for signal readout. The end-to-end performance analysis of the experimental chain, from the sensor to the DAQ, demonstrates that resonator thermal noise dominates the noise budget at temperatures well below 100 mK for all investigated modes. The measurements also verify proper thermalization of the resonator modes and rule out significant SQUID backaction on the strain sensor, confirming that the system operates close to its fundamental limits with comparable resonator thermal noise and additive readout noise. From this characterization, we derive projected strain sensitivities in the range $1−−10 \times 10^{-21}\,\mathrm{Hz}^{-1/2}$ for several resonant frequencies between 5 and 20~MHz, with corresponding fundamental thermal limits in the range $0.7−−1.4 \times 10^{-21}\,\mathrm{Hz}^{-1/2}$. Equipped with three resonators and synchronized to an absolute global time reference for multi-site coincidences, the antenna is ready to enter a pilot science run.
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BibTeX
@misc{albani2026demonstrating,
title = {{Demonstrating the thermal noise limit in a backaction-free bulk acoustic wave resonator chain for gravitational wave detection}},
author = {G. Albani and M. Borghesi and L. Canonica and R. Carobene and F. De Guio and M. Faverzani and N. Ferreiro Iachellini and E. Ferri and R. Gerosa and A. Ghezzi and A. Giachero and D. Labranca and L. Mariani and R. Maifredi and A. Nucciotti and D. Rozza and T. Tabarelli de Fatis},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.14020},
eprint = {2609.14020},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.14020},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Demonstrating the thermal noise limit in a backaction-free bulk acoustic wave resonator chain for gravitational wave detection
AU - G. Albani
AU - M. Borghesi
AU - L. Canonica
AU - R. Carobene
AU - F. De Guio
AU - M. Faverzani
AU - N. Ferreiro Iachellini
AU - E. Ferri
AU - R. Gerosa
AU - A. Ghezzi
AU - A. Giachero
AU - D. Labranca
AU - L. Mariani
AU - R. Maifredi
AU - A. Nucciotti
AU - D. Rozza
AU - T. Tabarelli de Fatis
PY - 2026
DA - 2026/09/12
PB - arXiv
DO - 10.48550/arxiv.2609.14020
UR - https://arxiv.org/abs/2609.14020
AB - We report the full sub-Kelvin characterization of the BAUSCIA high-frequency gravitational-wave antenna, based on cryogenic Bulk Acoustic Wave resonators coupled to SQUID amplifiers for signal readout. The end-to-end performance analysis of the experimental chain, from the sensor to the DAQ, demonstrates that resonator thermal noise dominates the noise budget at temperatures well below 100 mK for all investigated modes. The measurements also verify proper thermalization of the resonator modes and rule out significant SQUID backaction on the strain sensor, confirming that the system operates close to its fundamental limits with comparable resonator thermal noise and additive readout noise. From this characterization, we derive projected strain sensitivities in the range $1−−10 \times 10^{-21}\,\mathrm{Hz}^{-1/2}$ for several resonant frequencies between 5 and 20~MHz, with corresponding fundamental thermal limits in the range $0.7−−1.4 \times 10^{-21}\,\mathrm{Hz}^{-1/2}$. Equipped with three resonators and synchronized to an absolute global time reference for multi-site coincidences, the antenna is ready to enter a pilot science run.
ER -