Assistant Professor of Chemistry
Department of Chemistry
208 Stanley Hall, U.C. Berkeley
Berkeley, CA 94720
Phone: (617) 233-1871
Physical Chemistry — nanoscale NMR spectroscopy, targetable spin hyperpolarization agents, methods for quantum sensing and quantum computing with spins, and the chemical physics of spin transport and dynamics at the nanoscale.
Nuclear spins are ubiquitous, constituting everything around us, and are quantum objects endowed with extremely long coherence times. They do not participate in chemical reactions, but report on their local chemical environment, making them excellent reporters of chemical structure. NMR spectroscopy can probe these spins but suffer from several technical limitations.
We are innovating a new paradigm of deployable NMR probes, with the aim of enabling NMR spectroscopy within natural sample environments. By "bringing NMR to the sample" with nanoscale spatial resolution, we harness the exquisite chemical specificity of NMR to reveal insights into reaction mechanisms in-situ.
NMR Quantum Microscopy
NMR spectroscopy probes nuclear spins in samples non-invasively and with high chemical specificity. However, NMR suffers from poor spatial resolution and is not easily deployed naturally within sample environments.
We develop new tools for "NMR microscopy" leveraging quantum sensors to allow NMR spectroscopy at nanoscale resolution. This portends new chemical probes of reactions at interfaces and confined volumes (e.g. inside cells) and opens avenues for high throughput chemical screening and analysis.
Methods for Nuclear Spin Hyperpolarization
External probes of nuclear spins suffer from weak signals, stemming from low polarization (alignment) of spins in a magnetic field. This low sensitivity is an unfortunate consequence of the weak interaction of nuclei with their environments, a property that is ultimately responsible for the chemical specificity of NMR. We are innovating new methods of enhancing NMR signals with optical illumination by arranging for optical-spin "hyperpolarization".
'We exploit engineered optically polarizable electrons to serve as engines for nuclear spin cooling, allowing polarization levels that are several orders of magnitude beyond that conventionally possible. This promises new classes of portable NMR and MRI devices marrying together the specificity of NMR with the ubiquity and low-cost of a laser.
Quantum Sensing and Computing
Our work harnesses the fragility of quantum systems to deploy them as sensors in real-world chemical environments and condensed matter settings. The protocols and techniques we develop are directly relevant to quantum computing and quantum metrology.
Inspired by quantum error correction, we develop quantum control methods for exploiting entanglement to push limits of NMR spectroscopy towards single-molecule levels.
Probes of Nanoscale Spin Dynamics
The several-second long coherence of hyperpolarized nuclear spins allows new perspectives to probe quantum systems far from equilibrium. This allows new insights into a variety of phenomena, including spin localization, thermalization, and spin diffusion, allowing probes to the fundamentals of quantum statistical mechanics.
Practically, this could lead to new classes of spintronic devices that marry together spin, charge, and light for quantum information processing, and for high-density optically addressable quantum memories.
- Born 1987
- B.E./M.S. from BITS-Pilani, India, 2010
- Ph.D., MIT (Prof. Paola Cappellaro, advisor), 2016
- Postdoctoral Fellow, Univ. of California, Berkeley (Prof. Alex Pines, advisor), 2016-2020