Search for New Physics with Levitated Ferromagnetic Spin Sensor

by Prof. Wei Ji（季伟） (Peking University)

Wednesday 23 Apr 2025, 12:00 → 14:00 Asia/Shanghai

5#/6th-603 - Meeting Room 603 (Science Building)

Abstract:

In this talk, I will briefly discuss some of the key challenges in fundamental physics, including dark matter and new interactions beyond the Standard Model. I will then introduce spin-based sensors designed to address these challenges. The main technique I will focus on is the levitated ferromagnetic spin sensor, which offers significant advantages due to its weak coupling with the environment, enabling superior noise isolation[1][2]. Additionally, the strong spin correlation within the ferromagnetic sensor provides promising noise suppression and signal enhancement capabilities, particularly in experiments probing the low-frequency regime. These features make levitated ferromagnetic spin sensors highly sensitive and well-suited for both new physics searches and real-world applications.
[1] F. Ahrens., W.Ji, D. Budker et al, Levitated Ferromagnetic Magnetometer with Energy Resolution Well Below ℏ. Phys. Rev. Lett. 134(11), 110801(2025).
[2] S. Kalia, D. Budker; D. F. J Kimball, W. Ji et al, Ultralight Dark Matter Detection with Levitated Ferromagnets. Phys. Rev. D 2024, 110 (11), 115029（2025）.

Biography:

Ji Wei is an assistant professor at the School of Physics, Peking University, and a Boya Young Scholar at Peking University. He has long been engaged in research on precision magnetic measurements and the precise testing of the Standard Model of particle physics, including the search for new interactions beyond the Standard Model and dark matter. He has developed polarized atomic magnetometers and novel levitated ferromagnetic sensors, promoting their applications in fields such as particle physics and biomedical physics. Using ultra-sensitive atomic magnetometers and high-density spin sources, he has established the most stringent experimental limits to date on new interactions between electron-electron, electron-proton, and neutron-neutron pairs. His related research findings have been published in journals such as Physical Review Letters, Science Advances, and Nature Communications. He has been invited to write a comprehensive review on the detection of new interactions for Reviews of Modern Physics.

Host: Prof. Mengjiao Xiao

Alternative online link：https://meeting.tencent.com/dm/ikoIxks2HwfO

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