Squeezed phase noise: δφ_sqz = e^{−r}/√N (Caves 1981)

Caves 1981 squeezed-state Mach-Zehnder phase-estimation: injecting a squeezed-vacuum state with squeezing parameter r (amplitude e^{−r} < 1 suppressing phase-quadrature variance e^{+r} > 1 amplifying amplitude-quadrature) into the…