Quantum counterfactuality with identical particles

TL;DR

This paper demonstrates how quantum counterfactuality can be achieved using interference between identical particles, expanding the understanding of indistinguishability and its role in quantum information protocols.

Contribution

It introduces a novel approach to quantum counterfactuality based on particle indistinguishability related to first-order coherence, distinct from traditional mode operator concepts.

Findings

Counterfactual information transmission without particles in the channel

Implementation feasible with minor modifications to existing quantum protocols

Differentiates between types of indistinguishability in quantum interference

Abstract

Quantum self-interference enables the counterfactual transmission of information, whereby the transmitted bits involve no particles traveling through the channel. In this work, we show how counterfactuality can be realized even when the self interference is replaced by interference between identical particles. Interestingly, the facet of indistinguishability called forth here is associated with first-order coherence, and is different from the usual notion of indistinguishability associated with the (anti-)commutation relations of mode operators. From an experimental perspective, the simplest implementation of the proposed idea can be realized by slight modifications to existing protocols for differential-phase-shift quantum key distribution or interaction-free measurement.