Probing Non-Equilibrium Quantum Dynamics with Spins in Diamond and hBN

Washington University, Saint Louis MO

Investigators

Abstract

This project utilizes quantum spin defects hosted in diamond and atomically thin hexagonal boron nitride (hBN) to study how quantum systems behave when pushed away from equilibrium and how our everyday classical behavior emerges from underlying rules. These spin defects can be prepared and read out with optical light at room temperature, making them an ideal quantum platform without the need for complex cryogenic or vacuum hardware. Insights from these studies enable a better understanding of and prediction of the behavior of a complex quantum system and guide the design of improved quantum based simulators and sensors with important applications in science, technology, and national needs. The project also involves extensive education and outreach activities: developing an advanced undergraduate quantum laboratory, launching an annual “quantum open house” for regional colleges, and engaging secondary-school students and teachers across the greater St. Louis area through existing partnerships (e.g., the NSF NRT program in quantum sensing and the St. Louis Area Physics Teachers Association). Technically, the project will develop and employ two complementary room-temperature solid-state spin platforms: 3D ensembles of nitrogen vacancy (NV) centers in diamond and 2D spin defects in hBN. Both platforms offer unique advantages: a large number of quantum spins, optical initialization and readout at room temperature, long quantum coherence and lifetimes, strong and tunable long-range interaction, disorder, and dimensionality. Leveraging three distinct microscopic tuning knobs of the system Hamiltonian --- external driving, long-range interaction and dimensionality, the researchers will explore three exciting open questions in non-equilibrium quantum dynamics, (1) What novel phenomena can manifest when the constraint of time periodicity (Floquet) is relaxed for a driven system? (2) How do our everyday macroscopic classical phenomena emerge from microscopic quantum laws in the presence of different ranges of interaction? (3) Can distinct quantum phases and states be generated in lower dimensions? Expected outcomes include deeper understanding of out-of-equilibrium quantum phases, protocols for preserving quantum coherence relevant to quantum metrology, and benchmarks that connect controllable quantum platforms to complex real materials. 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.