High-energy nuclear collisions exhibit collective flow, which emerges as a dynamical response of the quark-gluon plasma (QGP) to initial state geometry collision. Collective flow in heavy-ion is usually described within multistage evolution models, employ viscous relativistic hydrodynamic description space-time QGP. By comparing event-by-event simulations kinetic theory and hydrodynamics OO, AuAu PbPb at energies Relativistic Heavy Ion Collider (RHIC) LHC, we quantify what extent macroscopic...

We simulate the space-time dynamics of high-energy collisions based on a microscopic kinetic description in conformal relaxation time approximation, order to determine range applicability an effective relativistic viscous hydrodynamics. find that hydrodynamics provides quantitatively accurate collective flow when average inverse Reynolds number is sufficiently small and early pre-equilibrium stage properly accounted for. further discuss implications our findings for (in)applicability...

We study a quantum fermion field inside cylinder in Minkowski space-time. On the surface of cylinder, satisfies either spectral or MIT bag boundary conditions. define rigidly-rotating states both cases, assuming that radius is sufficiently small speed-of-light excluded from With this assumption, we calculate thermal expectation values condensate, neutrino charge current and stress-energy tensor relative to bounded vacuum state. These are finite everywhere on their detailed properties depend...

We revisit the definition of rotating thermal states for scalar and fermion fields in unbounded Minkowski space-time. For such are ill-defined everywhere, but an appropriate vacuum gives regular inside speed-of-light surface. a massless field, we derive analytic expressions expectation values current stress-energy tensor. These may provide qualitative insights into behaviour on more complex space-time geometries.

We employ an effective kinetic description, based on the Boltzmann equation in relaxation time approximation, to study space-time dynamics and development of transverse flow small large collision systems. By combining analytical insights opacity limit with numerical simulations at larger opacities, we are able describe from very opacities. Surprisingly, find that deviations between theory hydrodynamics persist even which can be attributed presence early preequilibrium phase.

In this paper we discuss the analytical properties of binary collision integral for a gas ultrarelativistic particles interacting via constant cross section. Starting from near-equilibrium expansion over complete basis irreducible tensors in momentum space compute linearized matrices analytically. Using these results then numerically all transport coefficients relativistic fluid dynamics with various power-counting schemes that are second order Knudsen and/or inverse Reynolds numbers....

We consider the evolution equations for bulk viscous pressure, diffusion current, and shear tensor derived within second-order relativistic dissipative hydrodynamics from kinetic theory. By matching higher-order moments directly to quantities, all terms which are of second order in Knudsen number Kn vanish, leaving only $\mathcal{O}({\mathrm{Re}}^{\ensuremath{-}1}\mathrm{Kn})$ $\mathcal{O}({\mathrm{Re}}^{\ensuremath{-}2})$ relaxation equations, where ${\mathrm{Re}}^{\ensuremath{-}1}$ is...

The thermodynamics of rigidly rotating systems experience divergences when the system dimensions transverse to rotation axis exceed critical size imposed by causality constraint. with imaginary angular frequency, suitable for numerical lattice simulations in Euclidean imaginary-time formalism, experiences fractalization thermodynamic limit, system's pressure becomes a fractal function frequency. Our work connects two phenomena studying how fractalizes as grows. We examine an...

Helicity of free massless Dirac fermions is a conserved, Lorentz-invariant quantity at the level classical equations motion. For generic ensemble consisting particles and antiparticles, helical chiral charges are different conserved quantities. The flow helicity can be modelled by current, which again in absence interactions. Similar to axial vortical effect generates an (chiral) current induced vorticity finite temperature medium with vector (electrical) charge imbalance via effects,...

We evaluate the full opacity dependence of collective flow in high-energy heavy-ion collisions within a microscopic kinetic description based on Boltzmann equation conformal relaxation time approximation. By comparing theory calculations to hydrodynamic and hybrid simulations for an average initial state, we point out shortcomings inaccuracies models present modified simulation setups improve them.

In this paper we present a relativistic Shakhov-type generalization of the Anderson-Witting relaxation time model for Boltzmann collision integral. The extension is performed by modifying path on which distribution function ${f}_{\mathbf{k}}$ taken toward local equilibrium ${f}_{0\mathbf{k}}$, replacing ${f}_{\mathbf{k}}\ensuremath{-}{f}_{0\mathbf{k}}$ via ${f}_{\mathbf{k}}\ensuremath{-}{f}_{\mathrm{S}\mathbf{k}}$. Shakhov-like ${f}_{\mathrm{S}\mathbf{k}}$ constructed using...

Abstract In this paper, we consider the effect of interactions on local, average polarization a quantum plasma massless fermion particles characterized by vector, axial, and helical numbers. Due to axial vortical effects, perturbations in vector charge rotating can lead chiral transfer along direction vorticity vector. At same time, between constituents dissipation through helicity-violating pair annihilation (HVPA) processes anomaly. We will discuss separately QED-like plasma, which ignore...

In the present study, we investigate properties of an ensemble free Dirac fermions, at finite inverse temperature $\beta$ and chemical potential $\mu$, undergoing rigid rotation with imaginary angular velocity $\Omega_I$. Our purpose is to establish analytical structure such states, as well prospects (and dangers) extrapolating results obtained under case real rotation. We show that in thermodynamic limit, state system akin a stationary modified $\beta_q = q\beta$ same potential, where $q$...

Exploiting the first measurements of same ion species in OO collisions at Relativistic Heavy Ion Collider (RHIC) and LHC, we propose an observable to distinguish whether collective behavior builds up through a hydrodynamic expansion strongly interacting quark-gluon plasma or few final state rescatterings. Our procedure allows one disentangle effects initial geometry dynamical response mechanism on anisotropic flow. We validate its ability discriminate between systems with different...

We use the spherical coordinate system in momentum space and an appropriate discretization procedure to derive a hierarchy of lattice Boltzmann $(\mathrm{LB})$ models with variable temperature. The separation integrals into angular radial parts allows us compute moments equilibrium distribution function by means Gauss-Legendre Gauss-Laguerre quadratures, as well find elements discrete set for each $\mathrm{LB}$ model hierarchy. capability high-order this capture specific effects...

We present a systematic procedure for the construction of relativistic lattice Boltzmann models (R-SLB) appropriate simulation flows massless particles. Quadrature rules are used discretization momentum space in spherical coordinates. The optimized one-dimensional flows. applications considered this paper Sod shock tube and boost invariant expansion (Bjorken flow). Our tested against exact solutions inviscid ballistic limits. At intermediate relaxation times (finite viscosity), we compare...

In this paper, we study all transport coefficients of second-order dissipative fluid dynamics derived by V. E. Ambrus et al. [Phys. Rev. D 106, 076005 (2022)] from the relativistic Boltzmann equation in relaxation-time approximation for collision integral. These are computed a classical ideal gas massive particles, with and without taking into account conservation intrinsic quantum numbers. Through rigorous comparison between kinetic theory, dynamics, leading-order anisotropic...

The properties of a massive fermion field undergoing rigid rotation at finite temperature and chemical potential are discussed. polarisation imbalance is taken into account by considering helicity potential, which dual to the charge operator. advantage proposed approach that, as opposed axial current, current remains conserved mass. A computation thermal expectation values vector, currents, well condensate stress-energy tensor provided. In all cases, analytic constitutive equations derived...

The propagation properties of spin degrees freedom are analyzed in the framework relativistic hydrodynamics with based on de Groot--van Leeuwen--van Weert definitions energy-momentum and tensors. We derive analytical expression for wave velocity arbitrary statistics show that it goes to half speed light ultra-relativistic limit. find only transverse propagate, analogously electromagnetic waves. Finally, we consider effect dissipative corrections calculate damping coefficients case...

We derive the transport coefficients of second-order fluid dynamics with 14 dynamical moments using method and Chapman-Enskog in relaxation-time approximation for collision integral relativistic Boltzmann equation. Contrary to results previously reported literature, we find that derived two methods are perfect agreement. Furthermore, show that, unlike case binary hard-sphere interactions, diffusion-shear coupling ${\ensuremath{\ell}}_{V\ensuremath{\pi}}$,...

The Gauss-Laguerre quadrature method is used on the Cartesian semiaxes in momentum space to construct a family of lattice Boltzmann models. When all orders Qx, Qy, Qz equal N+1, Laguerre model LLB(Qx,Qy,Qz) exactly recovers moments up order N Maxwell-Boltzmann equilibrium distribution function f(eq), calculated over any octant three-dimensional space. Results Couette flow simulations at Kn=0.1, 0.5, 1.0 and ballistic regime are reported. Specific microfluidic effects (velocity slip,...

In the context of longitudinally boost-invariant Bjorken flow with transverse expansion, we use three different numerical methods to analyze emergence attractor solutions in an ideal gas massless particles exhibiting constant shear viscosity entropy density ratio $\ensuremath{\eta}/s$. The fluid energy is initialized using a Gaussian profile plane, while $\ensuremath{\chi}={\mathcal{P}}_{L}/{\mathcal{P}}_{T}$ between longitudinal and pressures set at initial time ${\ensuremath{\tau}}_{0}$...