Theorist developing frameworks for quantum sensing, control, and amplification in driven-dissipative quantum systems. Directions: (1) quantum noise theory for optomechanical and electromechanical sensors — fundamental limits and backaction evasion; (2) parametric amplification and squeezing beyond standard quantum limit; (3) non-reciprocal quantum systems for quantum-limited amplifiers; (4) quantum sensing theory for GW detectors and CMB experiments. 2020 Simons Investigator in Theoretical Physics.