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  • Open Access

Spin polarization of holographic baryon in strongly coupled fluid

Si-wen Li1,* and Shu Lin2,†

  • *Contact author: siwenli@dlmu.edu.cn
  • †Contact author: linshu8@mail.sysu.edu.cn
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Phys. Rev. D 112, 074009 – Published 8 October, 2025

DOI: https://doi.org/10.1103/jkv4-m723

Abstract

The spin polarization for a baryon in a hydrodynamic medium has been extensively studied in the weakly coupled regime using quantum kinetic theory. As a first study of this problem in the strongly coupled regime, we investigate holographically the spectral function of a probe baryon in the fluid-gravity background. This is done by carefully performing gradient expansion of the Dirac equation in the fluid-gravity background. Different contributions in the expansion are understood in terms of density matrices of the probe baryon and the medium. The resulting spectral functions indicate that the holographic baryon is polarized as responses to fluid acceleration, shear stress, and vorticity. The structures of the responses are similar to those found in weakly coupled studies.

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Corrections

4 February, 2026

Correction: A grant number in the Acknowledgments contained an error and has been fixed.

Article Text

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Outline

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Phys. Rev. D 112, 074009– Published 8 October, 2025
  • Received 18 June 2025
  • Accepted 15 September 2025
  • Corrected 4 February 2026
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