Remote Preparation of Optical Cat States Based on Gaussian Entanglement

Abstract

AbstractRemote state preparation enables one to prepare and manipulate quantum state non‐locally. As an essential quantum resource, optical cat state is usually prepared locally by subtracting photons from a squeezed vacuum state. For remote quantum information processing, it is essential to prepare and manipulate optical cat states remotely based on Gaussian entanglement, which remains a challenge. Here, experimental preparation of optical cat states based on a remotely distributed two‐mode Gaussian entangled state in a lossy channel is presented. By performing photon subtraction and homodyne projective measurement at Alice's station, an optical cat state is prepared remotely at Bob's station. Furthermore, the prepared cat state is rotated by changing Alice's measurement basis of homodyne detection, which demonstrates the remote manipulation of it. By distributing two modes of the two‐mode Gaussian entangled state in lossy channels, it is demonstrated that the remotely prepared cat state can tolerate much more loss in Alice's channel than that in Bob's channel. It is also shown that cat states with amplitudes larger than 2 can be prepared by increasing the squeezing level and subtracting photon numbers. The results make a crucial step toward remote hybrid quantum information processing involving discrete‐ and continuous‐variable techniques.