Session C07: Searches for Exotic Physics

Live

I will focus on exotic bosonic fields potentially sourced by powerful astrophysical events, such as binary neutron star and binary black hole mergers. Because such hypothetical fields are predicted to feebly interact with standard model particles and fields, we propose to employ precision quantum sensors to detect potential bursts of such exotic fields. We show that to unambiguously correlate such bursts with gravitational wave triggers, the fields must be ultralight and ultrarelativistic. Moreover, networks of precision sensors are required to resolve the progenitor position in the sky thereby establishing a crucial coincidence with the more conventional, e.g., electromagnetic or gravitational wave, observations of the source. We show that within certain models, atomic clocks and magnetometers can be sensitive to intense bursts of exotic fields from astrophysical sources within the reach of current gravitational wave observatories. This opens an intriguing possibility for a novel, exotic physics, modality in multi-messenger astronomy.   

Live

During the last decades a great interest has arisen in high-precision atomic physics experiments aiming at searching for a New Physics beyond the Standard Model. One of the very promising scenarios of such experiments is the measurement of the isotope shift of atomic (or ionic) levels. Besides the nuclear properties, this shift is believed to be affected by the coupling of an atom or ion with new hypothetical boson particles. In this presentation, we will briefly discuss these beyond-the-Standard-Model effects and will argue that their analysis requires better understanding of "usual" interactions between electron cloud and nucleus. Special attention will be paid to the violation of the linearity of the King's plot. Based on the detailed calculations, performed for Be-like, B-like, and C-like Argon ions, we discuss the sizable nonlinearities that arise for light elements from the quadratic recoil effect [1]. We argue that this next-to-leading order effect may impose serious restrictions of a search of new long-range forces between electrons and a nucleus. [1] V. A. Yerokhin , R. A. M\"{u}ller, A. Surzhykov, P. Micke, and P. O. Schmidt, Phys. Rev. A \textbf{101}, 012502 (2020)   

Live

We normally think of large accelerators and massive detectors when we consider the frontiers of elementary particle physics, pushing to understand the universe at higher and higher energy scales. However, several tabletop low-energy experiments are positioned to discover a wide range of new physics beyond the Standard model, where feeble interactions require precision measurements rather than high energies. In high vacuum, optically-levitated dielectric nanospheres achieve excellent decoupling from their environment, making force sensing at the zeptonewton level (10-21 N) achievable. In this talk I will describe our progress towards using these sensors for tests of the Newtonian gravitational inverse square law at micron length scales. Optically levitated dielectric objects and optical cavities show promise for a variety of other applications, including searches for gravitational waves and Dark Matter. Finally, I will discuss the Axion Resonant InterAction Detection Experiment (ARIADNE), a precision magnetometry experiment using laser-polarized 3-He gas to search for a notable dark-matter candidate: the QCD axion.   

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