The nonequilibrium evolution of heavy-ion collisions is studied in the limit weak coupling at very high energy employing lattice simulations classical Yang-Mills equations. Performing largest classical-statistical to date, we find that dynamics longitudinally expanding plasma becomes independent details initial conditions. After a transient regime dominated by instabilities and free streaming, subsequent space-time governed nonthermal fixed point, where system exhibits self-similar...

We study the thermalization process in highly occupied non-Abelian plasmas at weak coupling. The nonequilibrium dynamics of such systems is classical nature and can be simulated with real-time lattice gauge theory techniques. provide a detailed discussion this framework elaborate on results reported J. Berges, K. Boguslavski, S. Schlichting, R. Venugopalan, Phys. Rev. D 89, 074011 (2014) along novel findings. demonstrate emergence universal attractor solutions, which govern evolution large...

High-energy nuclear collisions produce a nonequilibrium plasma of quarks and gluons which thermalizes exhibits hydrodynamic flow. There are currently no practical frameworks to connect the early particle production in classical field simulations subsequent evolution. We build such framework using Green's functions, calculated QCD kinetic theory, propagate initial energy-momentum tensor phase. demonstrate that this approach can be easily incorporated into existing simulations, leading...

We develop a macroscopic description of the space-time evolution energy-momentum tensor during pre-equilibrium stage high-energy heavy-ion collision. Based on weak coupling effective kinetic microscopic equilibration process (\`a la ``bottom-up''), we calculate nonequilibrium local background as well linear response to transverse energy and momentum perturbations for realistic boost-invariant initial conditions collisions. demonstrate how this framework can be used an event-by-event basis...

We compute baryon and electric charge deposition in high-energy heavy-ion collisions using the color glass condensate effective field theory, where at leading order, is deposited through multiple scatterings of valence quarks with a saturated gluon target. A simplified phenomenological formula derived to describe deposition, from which parametrical dependence collisional energy geometry can be extracted. present an approximate analytical prediction so-called stopping parameter <a:math...

Relativistic heavy ion collisions provide laboratory environments from which one can study the creation of a novel state matter, quark-gluon plasma. The existence such is postulated to alter mechanism and evolution charge production, then becomes manifest in correlations. We separation balancing charges at kinetic freeze-out by analyzing recent results on correlations for Au + $\sqrt{{s}_{\mathrm{NN}}}=200 \text{GeV}$. find that central collisions, spatial points are emitted characterized...

In this review, we examine the current theoretical and experimental status of chiral magnetic effect. We discuss possible future strategies for resolving uncertainties in interpretation including recommendations work, measurements based on data collected past five years, beam use coming years RHIC. specifically investigate case colliding nuclear isobars (nuclei with same mass but different charge) find compelling. recommend that a program isobar collisions to isolate effect from background...

We compute single and double inclusive gluon distributions in classical Yang–Mills simulations of proton–lead collisions extract the associated transverse momentum dependent Fourier harmonics v2(pT) v3(pT). Gluons have a large v2 initial state, while odd such as v3 vanish identically at time τ=0+. By τ≲0.4 fm/c final state effects evolution generate non-zero only mildly modify v2. Unlike hydrodynamic flow, these space anisotropies are uncorrelated with global spatial anisotropy collision. A...

Isolated quantum systems in extreme conditions can exhibit unusually large occupancies per mode. This over-population gives rise to new universality classes of many-body far from equilibrium. We present theoretical evidence that important aspects non-Abelian plasmas the ultra-relativistic limit admit a dual description terms Bose condensed scalar field theory.

The mass ordering of mean transverse momentum $⟨{p}_{T}⟩$ and the Fourier harmonic coefficient ${v}_{2}({p}_{T})$ azimuthally anisotropic particle distributions in high energy hadron collisions is often interpreted as evidence for hydrodynamic flow matter produced. We investigate an alternative initial state interpretation this pattern high-multiplicity proton-proton at LHC. QCD Yang-Mills equations describing dynamics saturated gluons are solved numerically with conditions obtained from...

We examine the origins of azimuthal correlations observed in high energy proton-nucleus collisions by considering simple example scattering uncorrelated partons off color fields a large nucleus. demonstrate how physics fluctuating glass condensate (CGC) effective theory generates these multiparticle and compute corresponding Fourier coefficients v_n within different CGC approximation schemes. discuss detail qualitative quantitative differences between will show recently introduced field...

We perform the first, to our knowledge, classical-statistical real time lattice simulations of topological transitions in nonequilibrium glasma weakly coupled but highly occupied gauge fields created immediately after collision ultrarelativistic nuclei. Simplifying description by employing SU(2) fields, and neglecting their longitudinal expansion, we find that rate is initially strongly enhanced relative thermal sphaleron transition decays with during thermalization process. Qualitative...

We exploit the concept of hydrodynamic attractors to establish a general relation between initial state energy and produced particle multiplicities in high-energy nuclear collisions. When combined with an ab initio model deposition, entropy production during pre-equilibrium phase naturally explains universal centrality dependence measured charged yields nucleus-nucleus further estimate density far-from-equilibrium discuss how our results can be used constrain non-equilibrium properties...

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...

A bstract We use QCD kinetic theory to compute photon production in the chemically equilibrating Quark-Gluon Plasma created early stages of high-energy heavy-ion collisions. do a detailed comparison pre-equilibrium rates thermal production. show that spectrum radiated from hydrodynamic attractor evolution satisfies simple scaling form terms specific shear viscosity η / s and entropy density dS dζ ∼ ( Tτ 1 3 ) 2 ∞ . confirm analytical predictions with numerical simulations. extracted function...

Correlations of azimuthal angles observed at the Relativistic Heavy Ion Collider have gained great attention due to prospect identifying fluctuations parity-odd regions in field sector QCD. Whereas observable interest related parity involves subtracting opposite-sign from same-sign correlations, STAR collaboration reported and correlations separately. It is shown here how momentum conservation combined with collective elliptic flow contributes significantly this class although not difference...

We extend the impact-parameter-dependent Glasma model to three dimensions using explicit small-$x$ evolution of two incoming nuclear gluon distributions. compute rapidity distributions produced gluons and early-time energy momentum tensor as a function space-time transverse coordinates. study correlations fluctuations initial geometry multiplicity make comparisons existing models for three-dimensional state.

We study the dynamics of nonequilibrium instabilities in anisotropically expanding systems. The most prominent example such a system is 'Glasma' context relativistic heavy-ion collision experiments, where expansion consequence approximately boost-invariant initial conditions. Here we consider problem parametric resonance scalar $N$-component quantum field theories with conditions, which similar spirit. find that many aspects can be treated analytically by introducing generalized conformal...

We present first calculations of the fluctuating gluon distribution in a proton as function impact parameter and rapidity employing functional Langevin form JIMWLK renormalization group equation. demonstrate that when including effects confinement by screening long range Coulomb field color charges, evolution is unitary. The large-x structure proton, characterized position three valence quarks, retains an effect on shape down to very small values x. determine dipole scattering amplitude size...

We present a real-time lattice approach to study the nonequilibrium dynamics of vector and axial charges in $SU(N)\ifmmode\times\else\texttimes\fi{}U(1)$ gauge theories. Based on classical description non-Abelian Abelian fields, we include dynamical fermions develop operator definitions for (improved) Wilson overlap that allow us manifestations anomaly from first principles. application this anomalous transport phenomena such as chiral magnetic effect (CME) separation (CSE) by studying...

Measurements of multiparticle correlations in the collisions small systems such as p+p, p/d/ 3 He+A show striking similarity to observations heavy-ion collisions. A number observables measured high-multiplicity events these resemble features that are attributed collectivity driven by hydrodynamics. However, alternative explanations based on initial-state dynamics able describe many characteristic measurements. In this brief review, we highlight some recent developments and outstanding issues...

We present a first-principles study of anomaly induced transport phenomena by performing real-time lattice simulations with dynamical fermions coupled simultaneously to non-Abelian SU(N_{c}) and Abelian U(1) gauge fields. Investigating the behavior vector axial currents during sphaleron transition in presence an external magnetic field, we demonstrate how interplay chiral separation effect leads formation propagating wave. further analyze dependence magnitude current propagation wave on...

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.

We present a new three-dimensional resolved model for the initial state of ultrarelativistic heavy-ion collisions, based on <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:msub><a:mi>k</a:mi><a:mo>⊥</a:mo></a:msub></a:math>-factorized color glass condensate (CGC) hybrid approach. The framework responds to need rapidity-resolved initial-state Monte Carlo event generator which can deposit relevant conserved charges (energy, charge, and baryon densities) both in midrapidity forward...

We perform classical-statistical real-time lattice simulations to compute spectral functions and momentum broadening of quarks in the presence strongly populated non-Abelian gauge fields. Based on a novel methodology extract for relativistic quarks, we find that distribution exhibit interesting nonperturbative features as function time due correlated kicks it receives from medium, eventually going over diffusive regime. diffusion coefficient mass range describing charm bottom sizable...