Upper Bounds for the Clock Speeds of Fault-Tolerant Distributed Quantum Computation using Satellites to Supply Entangled Photon Pairs

TL;DR

This paper derives upper bounds on the clock speeds of fault-tolerant distributed quantum computation enabled by satellite-based entanglement distribution, showing feasibility over various distances with specific rate limits.

Contribution

It provides a closed-form expression for the entanglement generation rate in satellite-based quantum networks for fault-tolerant quantum computing.

Findings

Statewide distances (~500-999 km): ~1 MHz clock rate

Continent-wide distances (~1000-4999 km): ~10 kHz clock rate

Transcontinental distances (>5000 km): ~100 Hz clock rate

Abstract

Despite recent advances in quantum repeater networks, entanglement distribution on a continental scale remains prohibitively difficult and resource intensive. Using satellites to distribute maximally entangled photons (Bell pairs) between distant stations is an intriguing alternative. Quantum satellite networks are known to be viable for quantum key distribution, but the question of if such a network is feasible for fault tolerant distributed quantum computation (FTDQC) has so far been unaddressed. In this paper we determine a closed form expression for the rate at which logical Bell pairs can be produced between distant fault-tolerant qubits using a satellite network to supply imperfect physical Bell pairs. With generous parameter assumptions, our results show that FTDQC with satellite networks over statewide distances (500-999 km) is possible for a collective clock rate on the order of 1 MHz while continental (1000-4999 km) and transcontinental (5000+ km) distances run on the order of 10 kHz and 100 Hz respectively.