Analysis of quantum-nondemolition measurement
William George Unruh · Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields · 1978
The quantum-nondemolition measurement process suggested by Braginsky and co-workers is analyzed and shown not to work because of the fundamentally linear coupling between the oscillator and the measuring apparatus. A second-order coupling would work but the effect is probably too small for experimental realization.