Generation of one-million-mode continuous-variable cluster state by unlimited time-domain multiplexing

TL;DR

This paper demonstrates the generation of over one million fully inseparable continuous-variable light modes using an improved time-domain multiplexing technique with feedback control, significantly advancing quantum optical cluster state scalability.

Contribution

The authors successfully scale up continuous-variable cluster states to over one million modes by implementing continuous feedback control to mitigate phase drifts, surpassing previous limitations.

Findings

Generated over one million fully inseparable light modes.

Implemented feedback control to stabilize phase and increase mode count.

Produced a dual-rail continuous-variable cluster state.

Abstract

In recent quantum optical continuous-variable experiments, the number of fully inseparable light modes has drastically increased by introducing a multiplexing scheme either in the time domain or in the frequency domain. Here, modifying the time-domain multiplexing experiment reported in Nature Photonics 7, 982 (2013), we demonstrate successive generation of fully inseparable light modes for more than one million modes. The resulting multi-mode state is useful as a dual-rail CV cluster state. We circumvent the previous problem of optical phase drifts, which has limited the number of fully inseparable light modes to around ten thousands, by continuous feedback control of the optical system.