Perrin Segura - Quantum Science and Engineering Seminar

Observation of Pairing In a Pfaffian Quantum Hall State of Ultracold Bosons

Quantum simulation with ultracold atoms is a powerful platform for understanding the microscopic foundations underlying fractional quantum Hall phases, where the interplay between particle interactions and a magnetic field gives rise to wave functions with distinctive correlations. The single-site control and imaging capabilities of a quantum gas microscope allow us to probe these correlations directly. Using artificial gauge fields and a bottom-up approach to engineering the ground state, we are able to create and study quantum hall states through their characteristic correlation signatures.

Our latest work sets out to apply this process to the Pfaffian state, sought-after topological phase predicted to host particularly exotic properties, such as non-abelian anyonic excitations and p-wave pairing. We prepare the state using three atoms on a 5x5 grid, and measure density correlations consistent with this pairing picture as described by the Moore-Read wave function: a pronounced suppression of local three-body correlations relative to the normal state, but a much weaker suppression of two-body correlations, representing a state where two particles form a pair that the third one avoids. We also implement a transport-style probe that serves as an analog of traditional Hall-drift measurements by tracking the transverse center-of-mass response of the Pfaffian state under a weak applied force. The observed drift velocity agrees with theory, establishing a route to extracting Hall response and related transport properties in optical-lattice FQH experiments.

This experiment represents an important step forward in making pfaffian states accessible to cold atom systems, and establishes a foundation from which we can extend efforts to building larger systems and measuring more complex variables.

Bio: Perrin Segura is currently a graduate student on the Rubidium Quantum Gas Microscope team in Markus Greiner's at Harvard University.