Schrödinger cat state preparation by non-Gaussian continuous variable gate

Abstract: We propose a non-Gaussian continuous variable (CV) gate which is able to conditionally produce superposition of two "copies" of an arbitrary input state well separated in the coordinate and momentum plane - a Schr\"odinger cate state. The gate uses cubic phase state of an ancillary oscillator as a non-Gaussian resource, an entangling Gaussian gate, and homodyne measurement which provides nonunique information about the target system canonical variables, which is a key feature of the scheme. We show that this nonuniqueness manifests problems which may arise by extension of the Heisenberg picture onto the measurement-induced evolution of CV non-Gaussian networks, if this is done in an approach commonly used for CV Gaussian schemes of quantum information.