Speaker
Description
The cosmic axion spin precession experiment (CASPEr) is a nuclear magnetic resonance experiment to search for axion and axion-like particles (ALPs) that possibly make up a significant portion of dark matter in the Universe [1,2]. Due to the pseudoscalar nature and the light mass of ALPs, they can be treated as a field exerting a time-varying torque on nuclear spins either directly or through the generation of an oscillating nuclear electric dipole moment. In CASPEr-gradient, a sample of nuclear spins is placed in a magnetic field which is tunable over a wide range, thereby changing the Larmor frequency. When the Larmor frequency approaches the Compton frequency of the ALP, a magnetization will build up which we intend to detect using superconducting quantum interference devices (SQUIDs). We are currently characterizing the performance of the setup by measuring spin-projection noise of protons. Recently, we showed how this noise source together with thermal and amplifier noise is expected to present itself in our search for ALPs [3]. We found that suppression of the circuit back-action will be especially important in order for the spin-projection noise limits of searches for axion-like dark matter to reach the quantum chromodynamic axion sensitivity.
[1] D. Budker, P. W. Graham, M. Ledbetter, S. Rajendran, and A. O. Sushkov, Proposal for a Cosmic Axion Spin Precession Experiment (CASPEr), Phys. Rev. X 4, 021030 (2014).
[2] D. F. Jackson Kimball, S. Afach, D. Aybas, J. W. Blanchard, D. Budker, G. Centers, M. Engler, N. L. Figueroa, A. Garcon, P. W. Graham, H. Luo, S. Rajendran, M. G. Sendra, A. O. Sushkov, T. Wang, A. Wickenbrock, A. Wilzewski, and T. Wu, Overview of the Cosmic Axion Spin Precession Experiment (CASPEr), in Microwave Cavities and Detectors for Axion Research, edited by G. Carosi and G. Rybka (Springer International Publishing, Cham, 2020), pp. 105–121.
[3] D. Aybas, H. Bekker, J. W. Blanchard, D. Budker, G. P. Centers, N. L. Figueroa, A. V. Gramolin, D. F. J. Kimball, A. Wickenbrock, and A. O. Sushkov, Quantum Sensitivity Limits of Nuclear Magnetic Resonance Experiments Searching for New Fundamental Physics, ArXiv:2103.06284 [Cond-Mat, Physics:Hep-Ph, Physics:Physics, Physics:Quant-Ph] (2021).
| Speaker | Yuzhe Zhang, Hendrik Bekker |
|---|
