Full Network Nonlocality in Open Network Configuration

23 March 2026

Title: Full Network Nonlocality in Open Network Configuration

Speaker: Dr. Sneha Munshi, CQuERE, The Chatterjee Group Centres for Research and Education in Science and Technology, Kolkata, India

Abstract of Talk : The nonlocality arising in a multi-party network involving multiple independent sources radically differs from the standard multipartite Bell nonlocality involving a single source. The notion of the full network nonlocality (FNN) [Phys. Rev. Lett.128, 010403 (2022)] characterizes the quantum correlations that cannot be reproduced by a local-nonlocal model featuring one local source and the rest of nonlocal no-signaling sources. However, the demonstration of FNN was limited to bilocal and trilocal star-shaped network scenarios involving three or two dichotomic measurements for edge parties. In this letter, we first demonstrate that a large class of prevailing net- work inequalities does not exhibit FNN. We then introduce an elegant set of arbitrary-party and unbounded-input network inequalities in star-shaped and linear-chain networks whose optimal quantum violation exhibits FNN, certifying that the nonlocality is genuinely distributed to the entire network. Contrasting to existing demonstration of FNN that inevitably require fixed-input and four-output elegant joint measurements for the central party, our generalized inequalities are more experimentally friendly, requiring only two output measurements. Moreover, our derivation of optimal quantum violation is fully analytic and devoid of assuming the dimension of the quantum system, thereby showcasing its potential for device-independent self-testing.

Profile of Speaker:

Google Scholar https://share.google/pYV4qJwOpx9QVO1Ko

Dr. Sneha Munshi  has completed her PhD from National Institute of Technology Patna, India in 2023. She then joined Indian Institute of Technology, Hyderabad, India as a Post Doctoral Fellow and received Chanakya Post Doctoral Fellowship, for two years.   She works in Quantum Information theory, specifically in Quantum Networks. This talk is based on her recent work on device-independent certification of Full Network Nonlocality (FNN) in arbitrary party unbounded input open network configuration [Phys. Rev. Lett. 134, 210203 (2025)].