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Realizing string breaking dynamics in a Z2 lattice gauge theory on quantum hardware

Constantia Alexandrou1,2, Andreas Athenodorou2, Kostas Blekos2, Georgios Polykratis2, and Stefan Kühn3

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Phys. Rev. D 112, 114506 – Published 4 December, 2025

DOI: https://doi.org/10.1103/r6sr-dv13

Abstract

We investigate static and dynamical aspects of string breaking in a Z2 lattice gauge theory coupled to Kogut-Susskind staggered fermions. Using tensor network simulations, we demonstrate that the static potential as well as the site-resolved configuration of the matter sites and gauge links allows us to identify the regimes in which string breaking occurs. Furthermore, we develop a variational quantum eigensolver that allows for reliably preparing the ground state of the theory in both the absence and presence of static charges and to capture the static aspects of the phenomenon. Carrying out state preparation on real quantum hardware for up to 19 qubits, we demonstrate its suitability for current quantum devices. In addition, we study the real-time dynamics of a flux tube between two static charges using both tensor networks and quantum hardware. Using a trotterization for the time-evolution operator, we are able to show that the breaking process starts with the creation of charges inside the string. These eventually redistribute toward the static charges and screen them, which leads to the breaking of the flux tube.

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Phys. Rev. D 112, 114506– Published 4 December, 2025
  • Received 7 May 2025
  • Accepted 12 November 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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