Modification of "Counterfactual communication protocols" which eliminates weak particle traces

TL;DR

This paper proposes a modification to existing counterfactual communication protocols that removes weak particle traces, thereby making the protocols genuinely counterfactual and addressing previous controversies.

Contribution

It introduces a simple modification to prior protocols that eliminates particle traces in the transmission channel, ensuring true counterfactuality.

Findings

The modified protocols leave no detectable trace in the transmission channel.

The approach clarifies the counterfactual nature of quantum communication.

Previous protocols had detectable traces, which this method successfully removes.

Abstract

Possibility to communicate between spatially separated regions, without even a single photon passing between the two parties, is an amazing quantum phenomenon. The possibility of transmitting one value of a bit in such a way, the interaction-free measurement, was known for quarter of a century. The protocols of full communication, including transmitting unknown quantum states were proposed only few years ago, but it was shown that in all these protocols the particle was leaving a weak trace in the transmission channel, the trace larger than the trace left by a single particle passing through the channel. This made the claim of counterfactuality of these protocols at best controversial. However, a simple modification of these recent protocols eliminates the trace in the transmission channel making all these protocols counterfactual.