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  • Open Access

Casimir-Polder potential on an excited atom near an atomic array

Annyun Das* and Kanu Sinha†

  • Wyant College of Optical Sciences and Department of Physics, University of Arizona, Tucson, Arizona 85721, USA

  • *Contact author: annyun@arizona.edu
  • †Contact author: kanu@arizona.edu
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Phys. Rev. Research 8, 023339 – Published 25 June, 2026

DOI: https://doi.org/10.1103/pww8-hfmd

Abstract

We develop a microscopic description of the fluctuation-mediated Casimir-Polder (CP) shifts on a “test” two-level atom placed near a two-dimensional atomic array of two-level atoms. We derive the resonant and off-resonant CP potentials experienced by the excited test atom using fourth-order perturbation theory, under the assumption that the test atom resonance is far detuned from those of the array atoms. The total potential on the test atom can be described as the sum of the pairwise resonant and off-resonant potentials resulting from its interaction with the individual atoms of the array. We analyze the asymptotic scaling of CP shifts as a function of the test atom-array separation, and its dependence on various system parameters: array spacing and size, and dipole orientation of the array atoms. Our results bridge the description of CP potential across two distinct regimes: from (1) a single-atom limit, where we recover the well-known two-atom van der Waals potential, to (2) a macroscopic boundary limit, where we demonstrate unconventional asymptotic scaling laws. We demonstrate that these scaling laws can be tuned via the microscopic parameters of the atomic array, establishing atomically controlled arrays as a versatile platform for tailoring fluctuation-induced quantum electrodynamics phenomena.

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Corrections

25 August, 2026

Correction: The previously published Fig. 2 contained an error and has been replaced. Minor errors in Eqs. (3) and (5) have been fixed.

Article Text

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Phys. Rev. Research 8, 023339– Published 25 June, 2026
  • Received 24 March 2026
  • Accepted 2 June 2026
  • Corrected 25 August 2026
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