- Open Access
Second-order spin hydrodynamics from Zubarev’s nonequilibrium statistical operator formalism
Phys. Rev. D 112, 036014 – Published 22 August, 2025
DOI: https://doi.org/10.1103/8jw8-9w1x
Abstract
Using the Zubarev’s nonequilibrium statistical operator formalism, we derive the second-order expression for the dissipative tensors in relativistic spin hydrodynamics, viz. rotational stress tensor (), boost heat vector (), shear stress tensor (), and bulk viscous pressure (). The first two ( and ) emerge due to the inclusion of the antisymmetric part in the energy-momentum tensor, which, in turn, governs the conservation of spin angular momentum (). As a result, new thermodynamic forces, generated due to the antisymmetric part of , contain the spin chemical potential. In this work, we have also taken the spin density () as an independent thermodynamic variable, in addition to the energy density and particle density, thereby resulting in two novel transport coefficients given by the correlation between spin density tensor and rotational stress tensor and vice versa. Additionally, the newly found terms in and are the artifacts of the new thermodynamic forces that arise due to the antisymmetric part of . Finally, we have derived the evolution equations for the aforesaid tensors: , , , and .
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References (69)
- L. Adamczyk et al., Global hyperon polarization in nuclear collisions: Evidence for the most vortical fluid, Nature (London) 548, 62 (2017).
- J. Adam et al., Global polarization of hyperons in collisions at , Phys. Rev. C 98, 014910 (2018).
- J. Adam et al., Polarization of () hyperons along the beam direction in collisions at , Phys. Rev. Lett. 123, 132301 (2019).
- F. Becattini, M. Buzzegoli, T. Niida, S. Pu, A.-H. Tang, and Q. Wang, Spin polarization in relativistic heavy-ion collisions, Int. J. Mod. Phys. E 33, 2430006 (2024).
- T. Niida and S. A. Voloshin, Polarization phenomenon in heavy-ion collisions, Int. J. Mod. Phys. E 33, 2430010 (2024).
- S. Maekawa, S. O. Valenzuela, E. Saitoh, and T. Kimura, Spin Current (Oxford University Press, New York, 2017), Vol. 22.
- F. Becattini and M. A. Lisa, Polarization and vorticity in the quark–gluon plasma, Annu. Rev. Nucl. Part. Sci. 70, 395 (2020).
- W. Florkowski, A. Kumar, Avdhesh, and R. Ryblewski, Relativistic hydrodynamics for spin-polarized fluids, Prog. Part. Nucl. Phys. 108, 103709 (2019).
- I. Karpenko and F. Becattini, Study of polarization in relativistic nuclear collisions at , Eur. Phys. J. C 77, 213 (2017).
- R.-H. Fang, L.-G. Pang, Q. Wang, and X.-N. Wang, Polarization of massive fermions in a vortical fluid, Phys. Rev. C 94, 024904 (2016).
- Y. Xie, D. Wang, and L. P. Csernai, Global polarization in high energy collisions, Phys. Rev. C 95, 031901 (2017).
- Y. Sun and C. M. Ko, hyperon polarization in relativistic heavy ion collisions from a chiral kinetic approach, Phys. Rev. C 96, 024906 (2017).
- W. Florkowski, A. Kumar, R. Ryblewski, and R. Samanta, Spin polarization evolution in a boost-invariant hydrodynamic background, Phys. Rev. C 100, 054907 (2019).
- Y.-C. Liu and X.-G. Huang, Anomalous chiral transports and spin polarization in heavy-ion collisions, Prog. Part. Nucl. Phys. 107, 103755 (2019).
- S. Shi, C. Gao, H. Liao, and Q. Wang, Relativistic hydrodynamics for spin-polarized fluids and its applications to spin alignments, Ann. Phys. (Amsterdam) 418, 168206 (2020).
- L.-G. Pang, S. Y. F. Liu, H. Tsukamoto, and X.-N. Wang, Shear-induced spin polarization in heavy-ion collisions, Phys. Rev. Lett. 127, 142301 (2021).
- S. Alzhrani, S. Ryu, and C. Shen, spin polarization in event-by-event relativistic heavy-ion collisions, Phys. Rev. C 106, 014905 (2022).
- M. Buzzegoli, Spin polarization in heavy-ion collisions induced by thermal vorticity and thermal shear, Proc. Sci. SPIN2023 (2024) 234 [arXiv:2405.09709].
- A. Palermo, E. Grossi, I. Karpenko, and F. Becattini, polarization in very high energy heavy ion collisions as a probe of the quark–gluon plasma formation and properties, Eur. Phys. J. C 84, 929 (2024).
- N. Weickgenannt and J.-P. Blaizot, Polarization dynamics from moment equations, Phys. Rev. D 109, 056019 (2024).
- Shuo Fang, Shi Pu, and Di-Lun Yang, Spin polarization and spin alignment from quantum kinetic theory with self-energy corrections, Phys. Rev. D 109, 034034 (2024).
- S. Bhadury, A. Das, W. Florkowski, Gowthama K. K., and R. Ryblewski, Polarization of spin- particles with effective spacetime dependent masses, Phys. Lett. B 849, 138464 (2024).
- W. Florkowski and M. Hontarenko, Generalized thermodynamic relations for perfect spin hydrodynamics, Phys. Rev. Lett. 134, 082302 (2025).
- W. Florkowski and M. Hontarenko, Boost-invariant spin hydrodynamics with spin feedback effects, Phys. Rev. C 111, 024909 (2025).
- S. Dey and A. Jaiswal, Rotational Brownian motion and heavy quark polarization in QCD medium, arXiv:2502.20352.
- X.-G. Huang, An introduction to relativistic spin hydrodynamics, arXiv:2411.11753.
- K. Hattori, M. Hongo, X.-G. Huang, M. Matsuo, and H. Taya, Fate of spin polarization in a relativistic fluid: An entropy-current analysis, Phys. Lett. B 795, 100 (2019).
- K. Fukushima and S. Pu, Spin hydrodynamics and symmetric energy-momentum tensors—A current induced by the spin vorticity -, Phys. Lett. B 817, 136346 (2021).
- W. Florkowski, B. Friman, A. Jaiswal, and E. Speranza, Relativistic fluid dynamics with spin, Phys. Rev. C 97, 041901 (2018).
- J.-H. Gao and Z.-T. Liang, Relativistic quantum kinetic theory for massive fermions and spin effects, Phys. Rev. D 100, 056021 (2019).
- K. Hattori, Y. Hidaka, and D.-L. Yang, Axial kinetic theory and spin transport for fermions with arbitrary mass, Phys. Rev. D 100, 096011 (2019).
- S. Li and H.-U. Yee, Quantum kinetic theory of spin polarization of massive quarks in perturbative QCD: Leading log, Phys. Rev. D 100, 056022 (2019).
- D.-L. Yang, K. Hattori, and Y. Hidaka, Effective quantum kinetic theory for spin transport of fermions with collsional effects, J. High Energy Phys. 07 (2020) 070.
- N. Weickgenannt, E. Speranza, X.-L. Sheng, Q. Wang, and D. H. Rischke, Generating spin polarization from vorticity through nonlocal collisions, Phys. Rev. Lett. 127, 052301 (2021).
- Y.-C. Liu, K. Mameda, and X.-G. Huang, Covariant spin kinetic theory I: Collisionless limit, Chin. Phys. C 44, 094101 (2020).
- S. Bhadury, W. Florkowski, A. Jaiswal, A. Kumar, and R. Ryblewski, Relativistic dissipative spin dynamics in the relaxation time approximation, Phys. Lett. B 814, 136096 (2021).
- S. Shi, C. Gale, and S. Jeon, From chiral kinetic theory to relativistic viscous spin hydrodynamics, Phys. Rev. C 103, 044906 (2021).
- S. Li, M. A. Stephanov, and H.-U. Yee, Nondissipative second-order transport, spin, and pseudogauge transformations in hydrodynamics, Phys. Rev. Lett. 127, 082302 (2021).
- D. She, A. Huang, D. Hou, and J. Liao, Relativistic viscous hydrodynamics with angular momentum, Sci. Bull. 67, 2265 (2022).
- M. Hongo, X.-G. Huang, M. Kaminski, M. Stephanov, and H.-U. Yee, Relativistic spin hydrodynamics with torsion and linear response theory for spin relaxation, J. High Energy Phys. 11 (2021) 150.
- D. Montenegro, L. Tinti, and G. Torrieri, Sound waves and vortices in a polarized relativistic fluid, Phys. Rev. D 96, 076016 (2017).
- D. Montenegro, L. Tinti, and G. Torrieri, Ideal relativistic fluid limit for a medium with polarization, Phys. Rev. D 96, 056012 (2017).
- D. Montenegro and G. Torrieri, Causality and dissipation in relativistic polarizable fluids, Phys. Rev. D 100, 056011 (2019).
- D. Montenegro and G. Torrieri, Linear response theory and effective action of relativistic hydrodynamics with spin, Phys. Rev. D 102, 036007 (2020).
- K. Jensen, M. Kaminski, P. Kovtun, R. Meyer, A. Ritz, and A. Yarom, Towards hydrodynamics without an entropy current, Phys. Rev. Lett. 109, 101601 (2012).
- A. D. Gallegos, U. Gursoy, and A. Yarom, Hydrodynamics of spin currents, SciPost Phys. 11, 041 (2021).
- A. D. Gallegos, U. Gursoy, and A. Yarom, Hydrodynamics, spin currents and torsion, J. High Energy Phys. 05 (2023) 139.
- F. Becattini, A. Daher, and X.-L. Sheng, Entropy current and entropy production in relativistic spin hydrodynamics, Phys. Lett. B 850, 138533 (2024).
- R. Biswas, A. Daher, A. Das, W. Florkowski, and R. Ryblewski, Relativistic second-order spin hydrodynamics: An entropy-current analysis, Phys. Rev. D 108, 014024 (2023).
- F. Becattini and F. Piccinini, The ideal relativistic spinning gas: Polarization and spectra, Ann. Phys. (Amsterdam) 323, 2452 (2008).
- F. Becattini and L. Tinti, The ideal relativistic rotating gas as a perfect fluid with spin, Ann. Phys. (Amsterdam) 325, 1566 (2010).
- F. Becattini and L. Tinti, Nonequilibrium thermodynamical inequivalence of quantum stress-energy and spin tensors, Phys. Rev. D 87, 025029 (2013).
- F. Becattini, W. Florkowski, and E. Speranza, Spin tensor and its role in non-equilibrium thermodynamics, Phys. Lett. B 789, 419 (2019).
- J. Hu, Kubo formulae for first-order spin hydrodynamics, Phys. Rev. D 103, 116015 (2021).
- D. N. Zubarev, A. V. Prozorkevich, and S. A. Smolyanskii, Derivation of nonlinear generalized equations of quantum relativistic hydrodynamics, Theor. Math. Phys. 40, 394 (1979).
- C. G. Van Weert, Maximum entropy principle and relativistic hydrodynamics, Ann. Phys. (N.Y.) 140, 133 (1982).
- W. Florkowski, B. Friman, A. Jaiswal, and E. Speranza, Relativistic fluid dynamics with spin, Phys. Rev. C 97, 041901 (2018).
- F. Becattini and D. Rindori, Extensivity, entropy current, area law, and Unruh effect, Phys. Rev. D 99, 125011 (2019).
- F. Becattini, A. Daher, and X.-L. Sheng, Entropy current and entropy production in relativistic spin hydrodynamics, Phys. Lett. B 850, 138533 (2024).
- D.-L. Wang, S. Fang, and S. Pu, Analytic solutions of relativistic dissipative spin hydrodynamics with Bjorken expansion, Phys. Rev. D 104, 114043 (2021).
- R. Biswas, A. Daher, A. Das, W. Florkowski, and R. Ryblewski, Boost invariant spin hydrodynamics within the first order in derivative expansion, Phys. Rev. D 107, 094022 (2023).
- A. Harutyunyan, A. Sedrakian, and D. H. Rischke, Relativistic second-order dissipative hydrodynamics from Zubarev’s non-equilibrium statistical operator, Ann. Phys. (Amsterdam) 438, 168755 (2022).
- A. Jaiswal, R. S. Bhalerao, and S. Pal, Complete relativistic second-order dissipative hydrodynamics from the entropy principle, Phys. Rev. C 87, 021901 (2013).
- P. Romatschke, Relativistic viscous fluid dynamics and non-equilibrium entropy, Classical Quantum Gravity 27, 025006 (2010).
- S. Dey and A. Das, Kubo formula for spin hydrodynamics: Spin chemical potential as leading order in gradient expansion, Phys. Rev. D 111, 074037 (2025).
- D. She, Y.-W. Qiu, and D. Hou, Relativistic second-order spin hydrodynamics: A Kubo-type formulation for the quark-gluon plasma, Phys. Rev. D 111, 036027 (2025).
- J. Hu, Cross effects in spin hydrodynamics: Entropy analysis and statistical operator, Phys. Rev. C 107, 024915 (2023).
- A. Hosoya, M.-A. Sakagami, and M. Takao, Nonequilibrium thermodynamics in field theory: Transport coefficients, Ann. Phys. (N.Y.) 154, 229 (1984).
- X.-G. Huang, A. Sedrakian, and D. H. Rischke, Kubo formulae for relativistic fluids in strong magnetic fields, Ann. Phys. (Amsterdam) 326, 3075 (2011).