[Paper Review] Single-particle communication through correlated noise

Hlér Kristjánsson, Wenxu Mao+1 more|arXiv (Cornell University)|Apr 13, 2020

Quantum Information and Cryptography4 citations

TL;DR

This paper demonstrates that a single quantum particle can exploit temporal correlations in noisy channels—specifically, white noise with time-correlated errors—to transmit classical information more effectively than classically possible. By coherently superposing transmission times, the particle accesses quantum advantages such as perfect bit transmission over channels with uncorrelated noise, and enables coherent superpositions of causal orders, unlocking new communication protocols beyond standard quantum channel advantages.

ABSTRACT

When a noisy communication channel is used multiple times, the errors occurring at different times generally exhibit correlations. Here we show that, contrary to classical intuition, a single quantum particle can probe these correlations and exploit them to carry a larger amount of information per channel use. In particular, we show that a transmission line that outputs white noise at every time step can exhibit correlations that enable a perfect communication of classical bits. The working principle of this phenomenon is the possibility to transmit a single quantum particle at an indefinite moment of time, by coherently controlling the moment of transmission. When multiple transmission lines are available, time-correlations can be used to simulate the application of quantum channels in a coherent superposition of alternative causal orders, and even to generate new communication advantages that are not accessible through the superposition of causal orders.

Motivation & Objective

• To investigate whether quantum particles can exploit temporal correlations in noisy channels to enhance classical communication.
• To explore how coherent superposition of transmission times enables information transfer in channels with white noise.
• To determine if time-correlated noise can simulate coherent superpositions of causal orders in quantum channels.
• To identify new communication advantages not accessible through standard quantum channel superpositions.

Proposed method

• The study models a communication channel where each time step outputs white noise, yet the noise exhibits temporal correlations.
• It employs a single quantum particle whose transmission time is coherently superposed across multiple time steps.
• The protocol uses quantum control over the timing of particle emission to probe and exploit correlations in the noise process.
• Theoretical analysis shows that the coherent superposition of transmission times allows the particle to extract information from the noise correlations.
• The framework enables simulation of quantum channels applied in a superposition of causal orders, even without prior entanglement.
• The method leverages quantum interference effects arising from indefinite causal order to enhance communication fidelity.

Experimental results

Research questions

• RQ1 Can a single quantum particle exploit temporal correlations in white noise to transmit classical information more reliably than classical systems?
• RQ2 How does coherent superposition of transmission times enable information extraction from uncorrelated noise processes?
• RQ3 To what extent can time-correlated noise simulate the effects of coherent superpositions of causal orders in quantum channels?
• RQ4 Are there communication advantages in this scheme that are not achievable through standard quantum channel superpositions?

Key findings

• A single quantum particle can achieve perfect classical communication over a channel that outputs white noise at each time step, despite the noise being uncorrelated in a classical sense.
• The key mechanism is the coherent superposition of transmission times, which allows the particle to probe and exploit hidden temporal correlations in the noise.
• The protocol enables the simulation of quantum channels applied in a superposition of causal orders, even without entanglement.
• This approach generates communication advantages not accessible through standard quantum channel superpositions or classical strategies.
• The scheme demonstrates that temporal correlations in noise can be harnessed as a resource for quantum communication, defying classical intuition.
• The results show that quantum control over timing can unlock information-theoretic advantages in noisy channels.