Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 1305.7234

Testing viscous and anisotropic hydrodynamics in an exactly solvable case

Wojciech Florkowski·Radoslaw Ryblewski·Michael Strickland
View original source ↗Read source document ↗Export metadata ↓

Abstract

We exactly solve the one-dimensional boost-invariant Boltzmann equation in the relaxation time approximation for arbitrary shear viscosity. The results are compared with the predictions of viscous and anisotropic hydrodynamics. Studying different non-equilibrium cases and comparing the exact kinetic-theory results to the second-order viscous hydrodynamics results we find that recent formulations of second-order viscous hydrodynamics agree better with the exact solution than the standard Israel-Stewart approach. Additionally, we find that, given the appropriate connection between the kinetic and anisotropic hydrodynamics relaxation times, anisotropic hydrodynamics provides a very good approximation to the exact relaxation time approximation solution.

Explore related subjects

nucl-thhep-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Wojciech Florkowski, Radoslaw Ryblewski, Michael Strickland. 2013-08-07. Testing viscous and anisotropic hydrodynamics in an exactly solvable case. https://doi.org/10.1103/physrevc.88.024903

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Bayesian analysis of the Coulomb breakup of C19

Coulomb breakup is a common experimental technique to study the structure of halo nuclei. Coupling a halo effective field theory (Halo-EFT) description of these nuclei to accurate reaction models provides an ideal tool to analyze such experiments. In particular, it enables us to sample the space of the low-energy constants of this EFT within a Bayesian approach. This allows us to infer nuclear-structure information from the reaction data in a systematic and reliable way. Moreover, it provides an estimate of the uncertainty on those structure observables. We apply this to re-analyze the Coulomb breakup of $^{19}$C measured on Pb at 67 MeV/nucleon in RIKEN [T. Nakamura et al. Phys. Rev. Lett. 83, 1112 (1999)]. We obtain a new and more accurate value for the one-neutron separation energy $S_n(^{19}\mathrm{C}) = 0.60 \pm 0.02$ MeV and an improved estimate of the asymptotic normalization constant of its bound state $C_{1/2^+} = 0.85 \pm 0.02$ fm$^{-1/2}$. In addition, we estimate the uncertainty related to other model inputs at about 15% on both structure observables.

nucl-th↗
arXiv2026

Strangeness-changing two-body weak currents from SU(3) chiral dynamics

We know of no microscopic calculation of the semileptonic strangeness-changing 2p2h current. We construct it at tree level for nubar [NN] -> l+ Y N' from vertices of the lowest-order SU(3) chiral Lagrangian: contact, meson-in-flight, baryon-pole and kaon-exchange families, both pn line assignments summed coherently, and decuplet poles with N -> Delta transition form factors and SU(3) route signs. The undressed vector current is the Noether current of the flavour rotation and satisfies the SU(3)-limit Ward identity pointwise. The axial current has a vertex-level kaon-pole completion fixed by the Goldberger-Treiman relation, whose divergence equals (m_s+m_u)P_su by construction; we omit the axial contact operator, its kaon-pole partner, and the remaining inverse-propagator and mass-splitting terms, and the form factors break the vector identity. The flavour routes allow a primary kaon-less Sigma+ n final state from a pp pair that no one-body weak vertex reaches; antisymmetrised, it is 1.13-1.20% of the isolated two-body hyperon rate over the seven charge channels. In a factorised free-pair benchmark, octet baryon poles carry 77% of the Lambda-channel incoherent family sum at 0.6 GeV but 43-58% at 1-5 GeV, where the decuplet carries 26-48%; the line assignments interfere destructively. The isolated two-body current is 0.81-0.87 times as Lambda-rich as the quasi-elastic one at 1-5 GeV (0.67-0.95 across prescriptions); the axial contact operator with its kaon-pole partner at the Lagrangian coefficient lowers this by 2-6%, and a Ward-compatible form-factor dressing changes it by about 4%. A correlation on every meson changes the composition by under 3%; a Landau-Migdal contact on the pions alone leaves kaon exchange unscreened and roughly triples Lambda/Sigma0. The KNY couplings carry the axial N -> Y flavour combinations, so the composition is not the quasi-elastic one rescaled.

nucl-th↗
arXiv2026

Orientational average in nuclear shape imaging: densities, correlations, and eccentricity in Ne-20

The orientational treatment of deformed nuclei in high-energy nuclear collisions have two ways, a rigid rotor and a wave-function rotor, in which nuclear densities in laboratory frame are constructed differently. We calculate the one- and two-body densities (including Pauli blocking effects), body-axis contour multipoles, and geometric eccentricity variances under a leading-order ultracentral mapping for Ne-20 in a deformed harmonic-oscillator model in the rigid and wave-function rotors. At fixed deformation parameter $κ$ in the model, the two constructions can give different laboratory radial moments and pair correlations. The body-axis transition-kernel contours in the wave-function rotor are generally more compact along the symmetry axis, and $β_{20}$, $β_{40}$, $\langle\varepsilon_2^2\rangle$ and $\langle\varepsilon_4^2\rangle$ lie below the rigid-rotor results in a wide range of $κ$. The relations among these quantities in each rotor are nevertheless similar in most scanned parameter space: $β_{40}$ and $\langle\varepsilon_2^2\rangle$ depend linearly on $β_{20}^{2}$, while the hexadecapole baseline-subtracted variance follows an approximate quadratic trend in the quadrupole one. The method can be extended to seek more sensitive quantities for rotational effects in the wave-function rotor.

nucl-th↗