Difficulty: Intermediate Reading time: 4 minutes Prerequisites: Psionics_Primer; basic general relativity. If this is too advanced: see Inertia_and_Mach_Effect For the formal version: see Mach_Effect_Propulsion Vital Stats: Born: (not publicly disclosed) Died: (living) Nationality: American Field: Theoretical and experimental physics Affiliation: California State University, Fullerton Active era: Early 21st century Key works: Fearn-Woodward 2015 AIAA; Fearn 2015 Foundations of Physics Heidi Fearn is an American physicist at California State University, Fullerton, who has collaborated extensively with James Woodward on the experimental and theoretical investigation of Mach-effect thrust proposals. She is also active in mainstream quantum optics and quantum-mechanical foundations. Fearn earned her PhD in physics at the University of Essex (UK) in 1988, working on cavity quantum electrodynamics. She held postdoctoral positions in the US and joined Cal State Fullerton, where she has been on the faculty since the early 1990s. Her primary publication record is in quantum optics — laser physics, cavity QED, photon statistics. Since the mid-2000s she has additionally collaborated on Mach-effect-thruster experiments and theory with Woodward. Mach-effect theoretical derivation: Fearn 2015 (Foundations of Physics 45: 1300) provides a careful re-derivation of the Mach-effect mass-fluctuation formula, addressing several of the standard mainstream-physics objections to Woodward's earlier derivations. The paper is one of the more rigorous technical treatments of the Mach-effect framework. Experimental Mach-effect programme: With Woodward and other CSUF collaborators, Fearn has co-authored AIAA Joint Propulsion Conference papers reporting Mach-effect thruster test results. The programme emphasises careful exclusion of thermal-expansion and electromagnetic-artifact mechanisms. Quantum optics: Approximately 50 mainstream papers on cavity QED, photon statistics, and quantum-optics foundations. Fearn's quantum-optics work is respected in mainstream physics. Her Mach-effect work is regarded with the same mixture of interest and skepticism as the broader Woodward programme. • Fearn, H., Woodward, J. F. (2015). "Recent results of an investigation of Mach-effect thrusters." AIAA Joint Propulsion Conference 2015-4082. • Fearn, H. (2015). "Mach's principle and impulsive thrust effects." Foundations of Physics 45: 1300–1318. Plus approximately 50 mainstream quantum-optics papers. • James Woodward • Mach Effect Propulsion • Inertia and Mach Effect • Cal State Fullerton Physics faculty page. • As above.