Towards a primary temperature sensor based on magnon-phonon quantum correlation

Here, we report on progress towards a primary thermometer based on the spectral noise correlation between the magnetic excitations of a ferromagnet and its vibrational energy [1, 2].

Temperatures of the system are directly extracted from the measured correlation spectra. Recent progress allows these measurements to be performed without backaction from the measurement [3]. Of primary interest is the temperature regime below 1 K, as well as at 13.8 K. To validate the measurements, we compare the measured value at 13.8 K with one read by the NRC-calibrated national standards thermometer installed in the same cryostat where the magnon-phonon correlation thermometer situates. By enabling the self-calibration of system temperature, the noise-correlation-based thermometer could serve as a quantum primary thermometer.

1. Quantum correlations from a room-temperature optomechanical cavity, T.P. Purdy, K.E. Grutter, K. Srinivasan, and J.M. Taylor, Science 356, 1265 (2017).

2. Magnon-Phonon Quantum Correlation Thermometry, C.A. Potts, V.A.S.V. Bittencourt, S. Viola Kusminskiy and J.P. Davis, Phys. Rev. Applied 13, 064001 (2020).

3. Dynamical Backaction Evading Magnomechanics, C.A. Potts, Y. Huang, V.A.S.V. Bittencourt, S. Viola Kusminskiy and J.P. Davis, Phys. Rev. B 107, L140405 (2022).