Large amplitude coherent state superposition generated by a time-separated two-photon subtraction from a continuous wave squeezed vacuum

TL;DR

This paper presents a theoretical analysis of generating large amplitude coherent state superpositions via a two-photon subtraction process from a continuous wave squeezed vacuum, emphasizing the multimode temporal structure involved.

Contribution

It introduces a Schrödinger picture approach to analyze the multimode structure of photon subtraction from CW squeezed vacuum, revealing the creation of a large amplitude superposition in one mode.

Findings

States are described by two temporal modes.

One mode acts as an ancillary to produce a large superposition.

The process enables controlled generation of coherent state superpositions.

Abstract

Theoretical analysis is given for a two-photon subtraction from a continuous wave (CW) squeezed vacuum with finite time separation between two detection events. In the CW photon subtraction process, the generated states are inevitably described by temporal mutimode states. Our approach is based on Schr\"{o}dinger picture which provides mathematically simple forms and an intuitive understanding of its multimode structure. We show that, in our process, the photon subtracted squeezed vacuum is generated in two temporal modes and one of these modes acts as an ancillary mode to make the other one a large amplitude coherent state superposition.