Classical and Quantum Frequency Combs for Satellite-based Clock Synchronization

TL;DR

This paper explores the potential of classical and quantum frequency combs for achieving high-precision clock synchronization in satellite networks, highlighting current capabilities and future prospects beyond quantum limits.

Contribution

It provides a comparative perspective on classical and quantum frequency combs for space-based clock synchronization, including current results and future challenges.

Findings

Classical frequency combs can synchronize remote optical clocks with current technology.

Quantum frequency combs have the potential to surpass the standard quantum limit in synchronization precision.

Challenges include deploying frequency combs effectively in space environments.

Abstract

The next generation of space-based networks will contain optical clocks embedded within satellites. To fully realize the capabilities of such clocks, high-precision clock synchronization across the networks will be necessary. Current experiments have shown the potential for classical frequency combs to synchronize remote optical clocks over free-space. However, these classical combs are restricted in precision to the standard quantum limit. Quantum frequency combs, however, which exhibit quantum properties such as squeezing and entanglement, provide pathways for going beyond the standard quantum limit. Here, we present our perspective on the prospects for practical clock synchronization in space using both classical and quantum frequency combs. We detail the current outcomes achievable with a classical frequency comb approach to synchronization, before quantifying the potential outcomes offered by quantum frequency combs. Challenges to be overcome in deploying frequency combs in space are presented, and the implications of almost-perfect synchronization for future space-based applications and experiments discussed.