“…In contrast, for continuous variable (CV) systems that also play an important role in quantum information, the standard techniques in use today are decades old, namely homodyne measurement [8,9] for optical photons and direct Wigner function measurement [10][11][12] for cavity QED. With the rapid development in CV quantum information processing, ranging from arbitrary state preparation [13] to universal quantum control [14,15] and from engineered dissipation [16,17] to quantum error correction [18,19], a large dimension of Hilbert space can be coherently controlled in experiments [12,20]. However, homodyne measurement might not be immediately applicable due to intrinsic nonlinearity preventing applying a very large displacement in cavity QED, and Wigner function measurement requires intensive data collection [20].…”