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  • Open Access

Nonlocal advantage of quantum coherence in top quarks

Saurabh Rai*,‡ and Jitendra Kumar†

  • *Contact author: saurabhrai@iitj.ac.in
  • †Contact author: jkumar@iitj.ac.in
  • ‡Present address: Indian Institute of Technology Kanpur, Kalyanpur, Kanpur 208016, Uttar Pradesh, India.
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Phys. Rev. D 112, 114043 – Published 26 December, 2025

DOI: https://doi.org/10.1103/dvqh-ytbk

Abstract

There is a growing interest in investigating top-quark systems using tools from quantum information theory. A key peculiarity of the top quark is that it decays before hadronization or spin decorrelation occurs, thereby preserving its spin information. This unique property enables direct access to spin correlations, making the top quark an ideal candidate for probing fundamental quantum correlations in high-energy physics processes. A wide range of concepts from quantum information theory, such as entanglement, Bell nonlocality, quantum steering, quantum discord, and fidelity, have been investigated in this context. Several of these measures have been employed as diagnostic tools to test the Standard Model and to search for possible signatures of physics beyond. However, the nonlocal advantage of quantum coherence (NAQC) has remained largely unexplored in this context. In this work, we present a detailed investigation of the NAQC in top quark pair production. We employ two complementary NAQC measures based on the l1 norm and the relative entropy of coherence. We also study the effect of angular averaging on these measures and assess the sensitivity of current LHC spin-correlation measurements to NAQC. Our findings reveal rich coherence structures and highlight NAQC as potentially a novel and complementary quantum signature in high-energy physics systems.

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Phys. Rev. D 112, 114043– Published 26 December, 2025
  • Received 30 May 2025
  • Accepted 9 December 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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