Formation time of quark–gluon plasma in heavy-ion collisions in the holographic shock wave model

Golubtsova

Gourgoulhon

2016

Using black brane solutions in 5d Lifshitz-like backgrounds with arbitrary dynamical exponent ν, we construct the Vaidya geometry, asymptoting to the Lifshitz-like spacetime, which represents a thin shell infalling at the speed of light. We apply the new Lifshitz-Vaidya background to study the thermalization process of the quark-gluon plasma via the thin shell approach previously successfully used in several backgrounds. We find that the thermalization depends on the chosen direction because of the spatial anisotropy. The plasma thermalizes thus faster in the transversal direction than in the longitudinal one. To probe the system described by the Lifshitz-like backgrounds, we also calculate the holographic entanglement entropy for the subsystems delineated along both transversal and longitudinal directions. We show that the entropy has some universality in the behavior for both subsystems. At the same time, we find that certain characteristics strongly depend on the critical exponent ν.

“…We see that the thermalization time behaves linearly with . The results match to those for modified AdS models from [34] and coincide for all values of the dynamical exponent ν.…”

Section: Jhep09(2016)142supporting

confidence: 76%

“…Further, we construct a Vaidya-type geometry asymptoting to the Lifshitz-like solution to model a gravitation collapse in order to study the holographic thermalization. The Vaidya metric with Lifshitz scaling was used for the examination of the holographic thermalization in [33,34]. There, it has been shown that for the metric…”

Section: Jhep09(2016)142mentioning

confidence: 99%

Analytic black branes in Lifshitz-like backgrounds and thermalization

Golubtsova

Gourgoulhon

2016

“…It is called the holographic entanglement entropy (HEE) and is defined as the area of a minimal surface extending from some predefined surface A on the boundary into the bulk [27][28][29]. The HEE during thermalization usually evolves to the thermal entanglement entropy [30][31][32][33][34][35][36][37][38]. With this approach, there is a natural possibility of studying the evolution of entropy in HIC (thermalization) and phase transitions for the obtained thermal media in the framework of the same holographic model.…”

mentioning

confidence: 99%

Holographic anisotropic background with confinement-deconfinement phase transition

Rannu

2018

We present new anisotropic black brane solutions in 5D Einstein-dilaton-twoMaxwell system. The anisotropic background is specified by an arbitrary dynamical exponent ν, a nontrivial warp factor, a non-zero dilaton field, a non-zero time component of the first Maxwell field and a non-zero longitudinal magnetic component of the second Maxwell field. The blackening function supports the Van der Waals-like phase transition between small and large black holes for a suitable first Maxwell field charge. The isotropic case corresponding to ν = 1 and zero magnetic field reproduces previously known solutions. We investigate the anisotropy influence on the thermodynamic properties of our background, in particular, on the small/large black holes phase transition diagram.We discuss applications of the model to the bottom-up holographic QCD. The RG flow interpolates between the UV section with two suppressed transversal coordinates and the IR section with the suppressed time and longitudinal coordinates due to anisotropic character of our solution. We study the temporal Wilson loops, extended in longitudinal and transversal directions, by calculating the minimal surfaces of the corresponding probing open string world-sheet in anisotropic backgrounds with various temperatures and chemical potentials. We find that dynamical wall locations depend on the orientation of the quark pairs, that gives a crossover transition line between confinement/deconfinement phases in the dual gauge theory. Instability of the background leads to the appearance of the critical points (µ ϑ,b , T ϑ,b ) depending on the orientation ϑ of quark-antiquark pairs in respect to the heavy ions collision line.

“…It is called the holographic entanglement entropy (HEE) and is defined as the area of a minimal surface extending JHEP07(2020)043 from some predefined surface A on the boundary into the bulk [28][29][30]. The HEE during thermalization usually evolves to the thermal entanglement entropy [31][32][33][34][35][36][37][38][39][40][41][42]. With this approach, there is a natural possibility of studying the evolution of entropy in HIC (thermalization) and phase transitions for the obtained thermal media in the framework of the same holographic model.…”

Section: Jhep07(2020)043mentioning

confidence: 99%

“…Figure34. Top line: vs z * for F=EF for ϕ = 0 (longitudinal case) at (a) z h = 1.2, 1.138, 1.108, 1 and µ = 0, at (b) z h = 2, 2.5, 3.0, 3.5 and µ = 0.5.…”

mentioning

confidence: 99%

Holographic entanglement entropy in anisotropic background with confinement-deconfinement phase transition

Patrushev

Slepov

2020

We discuss a general five-dimensional completely anisotropic holographic model with three different spatial scale factors, characterized by a Van der Waals-like phase transition between small and large black holes. A peculiar feature of the model is the relation between anisotropy of the background and anisotropy of the colliding heavy ions geometry. We calculate the holographic entanglement entropy (HEE) of the slab-shaped region, the orientation of which relatively to the beams line and the impact parameter is characterized by the Euler angles. We study the dependences of the HEE and its density on the thermodynamic (temperature, chemical potential) and geometric (parameters of anisotropy, thickness, and orientation of entangled regions) parameters. As a particular case the model with two equal transversal scaling factors is considered. This model is supported by the dilaton and two Maxwell fields. In this case we discuss the HEE and its density in detail: interesting features of this model are jumps of the entanglement entropy and its density near the line of the small/large black hole phase transition. These jumps depend on the anisotropy parameter, chemical potential, and orientation. We also discuss different definitions and behavior of c-functions in this model. The c-function calculated in the Einstein frame decreases while is increasing for all in the isotropic case (in regions of (µ, T )-plane far away from the line of the phase transition). We find the non-monotonicity of the c-functions for several anisotropic configurations, which however does not contradict with any of the existing c-theorems since they all are based on Lorentz invariance.