Practical Quantum Appointment Scheduling

TL;DR

This paper introduces a quantum protocol for appointment scheduling that reduces information leakage compared to classical methods, utilizing coherent states and linear optics, with implications for secure quantum communication.

Contribution

It presents a novel quantum protocol leveraging coherent states for appointment scheduling, with new tools for analyzing quantum information cost in finite regimes.

Findings

Protocol leaks less information than classical counterparts

Requires low-loss transfer of coherent states between parties

Develops new methods for quantum information cost analysis

Abstract

We propose a protocol based on coherent states and linear optics operations for solving the appointment-scheduling problem. Our main protocol leaks strictly less information about each party's input than the optimal classical protocol, even when considering experimental errors. Along with the ability to generate constant-amplitude coherent states over two modes, this protocol requires the ability to transfer these modes back-and-forth between the two parties multiple times with low coupling loss. The implementation requirements are thus still challenging. Along the way, we develop new tools to study quantum information cost of interactive protocols in the finite regime.