Entanglement boosts capacity in zero-delay classical relay channels
Can Quantum Entanglement Increase the Capacity of a Classical Relay Channel?
Information Theory
Summary
This paper looks at whether a quantum phenomenon called entanglement can help increase the amount of information sent through relay communication channels. The authors find that for relay channels with a delay before the relay sends information, entanglement does not help increase capacity. But for relay channels where the relay sends information without delay, sharing entanglement between the sender and relay can increase the communication rate by about 12.5%. This means entanglement can sometimes improve data transmission in relay networks.
What this means in practice
- •For network protocol engineers: Design relay communication protocols that exploit quantum entanglement to surpass traditional capacity limits in zero-delay relay setups.
- •For quantum communication device makers: Develop devices that share entanglement between source and relay to increase classical channel throughput in real-time relay systems.$Commercial implications: Enables commercial quantum-enhanced relays that can boost capacity for communication providers using zero-delay setups.
Authors
Elsa Mizrahi, Uzi Pereg
Abstract
We show positive and negative results on classical relay channels with entanglement assistance, revealing a sharp contrast between strictly causal and causal relay encoding. First, we consider van der Meulen's setting of a unit-delay relay, with strictly causal encoding. We show that the standard cutset upper bound continues to hold with entanglement assistance, and deduce that entanglement does not increase the capacity for several classes of relay channels. Second, we consider a zero-delay relay, where the encoding is causal. We present an example in which entanglement enables rates that exceed the cutset upper bound by at least 12.5%. Namely, entanglement shared between the source and relay significantly increases the capacity of a classical zero-delay relay channel.