A1 Refereed original research article in a scientific journal
Stability of continuous time quantum walks in complex networks
Authors: Adithya, L. J.; Nokkala, Johannes; Piilo, Jyrki; Meena, Chandrakala
Publisher: IOP Publishing
Publication year: 2026
Journal: Physica Scripta
Article number: 195103
Volume: 101
Issue: 19
ISSN: 0031-8949
eISSN: 1402-4896
DOI: https://doi.org/10.1088/1402-4896/ae6741
Publication's open availability at the time of reporting: No Open Access
Publication channel's open availability : Partially Open Access publication channel
Web address : https://doi.org/10.1088/1402-4896/ae6741
Understanding how decoherence disrupts quantum walks is vital for developing robust quantum technologies, as environmental interactions often degrade quantum properties or induce transitions to classical random walks. We investigate the stability of continuous-time quantum walks across different network topologies subjected to three distinct decoherence mechanisms: energy-based intrinsic decoherence, node-based Haken-Strobl noise, and edge-based quantum stochastic walk. By defining stability as the preservation of quantum properties, we find that densely connected networks, such as the complete network, and hub dominated networks, such as scale-free and star topologies, are stable under Haken-Strobl noise but become uniquely vulnerable under quantum stochastic walk. However, these same networks exhibit lower coherence in the noiseless regime due to their inherent localization, highlighting a fundamental trade-off between localization and coherence. Furthermore, the centrality of the initialization node has a pronounced impact on relaxation time, underscoring the critical role of local topological features in quantum dynamics.
Keywords:
complex networks, quantum coherence, quantum walks
Funding information in the publication:
ALJ acknowledges the University Grants Commission (UGC), India, for financial support. CM acknowledges support from the Anusandhan National Research Foundation (ANRF), India (Grant Numbers SRG/2023/001846 and EEQ/2023/001080), and the Department of Science and Technology (DST), Government of India, through the INSPIRE Faculty Award (No. IFA19-PH248). We are grateful to Dr. Luca Razzoli for helpful correspondence and for pointing us to his work [50], which provided the analytical explanation for the universality we observed in the star initial localization on the center node and complete network dynamics.
