Basis-Independent Coherence Dynamics of Tripartite States under Pure Dephasing

Research Overview

This paper investigates the dynamical behavior of intrinsic quantum coherence in tripartite systems (three-qubit states) when subjected to environmental noise. While most quantum information research relies on basis-dependent measures of coherence—which can change depending on the chosen reference frame—this study employs a basis-independent measure based on the quantum Jensen-Shannon divergence. By comparing this intrinsic measure against traditional metrics like the relative entropy of coherence, the authors provide a clearer picture of how quantum states maintain their coherence under realistic, noisy conditions.

The researchers modeled the evolution of various tripartite pure and mixed states (including GHZ, W, and Werner-type states) under two primary dephasing scenarios: local dephasing, where each qubit interacts with its own independent reservoir, and common dephasing, where all qubits interact with a single shared reservoir. The study further distinguishes between Markovian regimes (where information flows irreversibly from the system to the environment) and non-Markovian regimes (where environmental memory effects allow for the backflow of information).

Key Findings

The study reveals that basis-independent coherence is remarkably robust. In non-Markovian environments, the intrinsic coherence of both pure and mixed states remains nearly frozen, showing a level of resilience that is not captured by basis-dependent measures. Furthermore, the authors find that collective (common) dephasing environments can significantly enhance coherence preservation compared to local dephasing, as the collective interaction can lead to the emergence of decoherence-free subspaces. The results suggest that basis-independent measures provide a more accurate and stable characterization of quantum resources for practical quantum technologies.

Understanding how to preserve quantum coherence is essential for the development of scalable quantum computers and communication networks. By showing that intrinsic coherence is more resilient than previously thought, this work suggests that researchers may have been underestimating the stability of quantum information in noisy environments. This shift toward basis-independent quantification offers a more reliable framework for evaluating the performance of quantum systems in real-world, non-ideal conditions.