CAREER: Searching for New Physics with Nuclear Spins

Dark matter is an invisible substance that makes up more than eighty percent of the matter content of the universe. This research project aims to directly detect dark matter particles by exploring a broad range of possible dark matter masses. Recently, the fuzzy dark matter model has emerged as a promising candidate.

In this model, the particles that make up dark matter are so light that they spread out over large areas, rather than clustering in small groups. This characteristic could help explain the size of our galaxy and why there seems to be a minimum size limit for galaxies in general. The project is driven by interests in high-energy physics, but it presents considerable experimental challenges.

The research team plans to develop a new system designed to cast a wide net in the ongoing laboratory search for dark matter. The innovative techniques they create could not only help in the search for dark matter but also facilitate the discovery of new forces and enhance our ability to measure energy levels in quantum systems.

The research team will build a system to search for ultra-low mass dark matter by examining how it interacts with nuclear spins. Nuclear spin energy levels will fluctuate based on how they align with the flow of dark matter. As the Earth rotates and the dark matter oscillates, these energy levels will change, creating a unique pattern over time.

The most precise measurements of the energy differences between quantum states—measured in absolute terms—have been achieved using groups of optically “pumped” nuclear spins. This technique involves using light to control the orientation of a nucleus's spin, effectively aligning the nuclear spins in a specific direction through the manipulation of light.

There is still significant potential to enhance energy sensitivity using current technology. The research team's goal is to achieve a 30-fold improvement over the current best methods, with data readout conducted by a SQUID (Superconducting Quantum Interference Device).

The team will conduct two distinct dark matter searches: one targeting dark matter with a frequency higher than the Earth’s rotation rate, and another for dark matter with a mass lower than this rotation rate, that will include investigating the “Fuzzy” dark matter scenario.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.