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  • Open Access

Enhanced superresolution by entanglement of the unified quantum wave function

Abdelali Sajia and Xiao-Feng Qian*

  • *Contact author: xqian6@stevens.edu
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Phys. Rev. Research 7, 033219 – Published 4 September, 2025

DOI: https://doi.org/10.1103/pt7n-5gmr

Abstract

When two point sources are separated by less than the Abbe-Rayleigh limit, conventional resolution methods fail to distinguish whether there is one source or two. Consequently, it becomes nearly impossible to resolve important relative properties of the two sources, such as mutual coherence, relative phase, and brightness contrast. In this regime, the incoming composite quantum signal must be treated as a single entity described by an overall quantum wave function. In this study, we explore the superresolution of such two-point sources by examining a special wave property, i.e., entanglement between spatial degree of freedom (DoF) and remaining DoFs (both internal and external). Remarkably, we find that increasing this inter-DoF entanglement enhances the precision of superresolution, as quantified by the quantum Fisher information (QFI) in single-parameter estimation. Moreover, we show that this entanglement reliably ensures a nonvanishing QFI in two-parameter estimation, highlighting its role as a valuable resource for quantum superresolution.

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Phys. Rev. Research 7, 033219– Published 4 September, 2025
  • Received 21 September 2024
  • Accepted 28 July 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.

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