# Quantum coherence of multiqubit states in correlated noisy channels

## TL;DR

This paper investigates how classical correlations in noisy channels can delay quantum decoherence in multiqubit systems, showing that correlated noise preserves coherence longer, especially in larger systems.

## Contribution

It demonstrates that classical correlations in noisy channels can significantly delay quantum decoherence in multiqubit states, with larger systems exhibiting greater robustness.

## Key findings

- Correlated noise delays quantum coherence decay.
- Larger multiqubit systems maintain coherence longer.
- Interplay between quantum coherence and total correlations explains decoherence delay.

## Abstract

The long-time maintenance of quantum coherence is crucial for its practical applications. We explore decoherence process of a multiqubit system passing through a correlated channel (phase flip, bit flip, bit-phase flip, and depolarizing). The results show that the decay of coherence was evidently delayed when the consecutive actions of the channel on the sequence of qubits has some classical correlations. In particular, the relative entropy of coherence for a system with large number of qubits is more robust than that with small number of qubits. We also provide an explanation for the delayed decoherence by exploring the interplay between the change of the unlocalized quantum coherence and the total correlation gain of the multiqubit system.