  As an application of the simultaneous and continuous measurement of
noncommutative observables formulated in our previous paper [C. Jiang and G.
Watanabe, Phys. Rev. A 102, 062216 (2020)], we propose a scheme to generate the
pure ideal quadrature-squeezed state in a one-dimensional harmonic oscillator
system by the feedback control based on such type of measurement of
noncommutative quadrature observables. We find that, by appropriately setting
the strengths of the measurement and the feedback control, the pure ideal
quadrature-squeezed state with arbitrary squeezedness can be produced. This is
in contrast to the scheme based on the single-observable measurement and the
feedback control, where only nonideal squeezed states with squeezing of the
measured quadrature are produced.
