# Non-Gaussian quantum states of a multimode light field

## TL;DR

This paper demonstrates the generation of non-Gaussian multimode quantum states by photon subtraction, revealing non-Gaussianity spread among entangled modes, which advances quantum network applications.

## Contribution

First experimental realization of non-Gaussian multimode quantum states through photon subtraction from Gaussian states.

## Key findings

- Negativity of the Wigner function observed
- Non-Gaussianity spreads among entangled modes
- Potential applications in quantum networks

## Abstract

Even though Gaussian quantum states of multimode light are promising quantum resources due to their scalability, non-Gaussianity is indispensable for quantum technologies, in particular to reach quantum computational advantage. However, embodying non-Gaussianity in a multimode Gaussian state remains a challenge as controllable non-Gaussian operations are hard to implement in a multimode scenario. Here, we report the first generation of non-Gaussian quantum states of a multimode light field by subtracting a photon in a desired mode from multimode Gaussian states, and observe negativity of the Wigner function. For entangled Gaussian states, we observe that photon subtraction makes non-Gaussianity spread among various entangled modes. In addition to applications in quantum technologies, our results shed new light on non-Gaussian multimode entanglement with particular emphasis on quantum networks.