Pictorial interpretation of quantum-enhanced measurements with wave functions

Quantum-enhanced measurements using squeezed states of light provide sensitivities beyond the shot noise limit. Although the mechanism of quantum enhancement is well described by quantum mechanics, it is difficult to intuitively understand how squeezed states are exploited. In this paper, we present a pictorial interpretation of quantum-enhanced measurements using wave functions, which provides intuitive pictures of squeezed states in various experimental systems.