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## Thermal Transport and Drag Force in Improved Holographic QCD (2009)

Citations: | 5 - 0 self |

### Citations

265 |
Starinets, Shear viscosity of strongly coupled N = 4 supersymmetric Yang-Mills plasma
- Policastro, Son, et al.
(Show Context)
Citation Context ...zes. Relativistic hydrodynamics describes very well the QGP [2, 3], with a shear-viscosity to entropy density ratio close to the universal value suggested by the holographic formulation of N = 4 SYM, =-=[4]-=-. The QGP is at strong coupling, and it necessitates a treatment beyond perturbative QCD approaches, [5]. There are several observables that seem to be important in understanding measured features of ... |

230 | Energy loss of a heavy quark moving through N = 4 supersymmetric Yang-Mills plasma
- Herzog, Karch, et al.
- 2006
(Show Context)
Citation Context ...5 4 ] √2λ pi 32T 3 (1.1) A different approach chooses to compute the drag force acting a string whose UV end-point (representing an infinitely heavy quark) is forced to move with constant velocity v, =-=[21, 22, 23]-=-, in the context of N = 4 SYM plasma. The result for the drag force is Fconformal = pi 2 √ λ T 2 v√ 1− v2 (1.2) and is calculated by first studying the equilibrium configuration of the appropriate str... |

195 | Starinets, “Viscosity in strongly interacting quantum field theories from black hole physics - Kovtun, Son, et al. - 2005 |

158 |
Calculating the jet quenching parameter from AdS/CFT
- Liu, Rajagopal, et al.
(Show Context)
Citation Context ... while perturbative approaches are trustworthy at much lower values. – 3 – Several attempts were made to compute quark energy loss in the holographic context, relevant for N = 4 SYM2. In some of them =-=[19, 20]-=- the jet-quenching coefficient q̂ was calculated via its relationship to a light-like Wilson loop. Holography was then used to calculate the appropriate Wilson loop. The q̂ obtained scales as√ λ and a... |

143 |
QCD and a holographic model of hadrons,” Phys
- Erlich, Katz, et al.
(Show Context)
Citation Context ...e range, [33],[34],[35]. A holographic description of QCD has been elusive, and the best we have so far have been simple bottom up models. In the simplest bottom-up holographic model known as AdS/QCD =-=[36]-=-, the bulk viscosity is zero as conformal invariance is essentially not broken (the stress tensor 2Most are reviewed in [18]. – 4 – is traceless), and the drag force and jet quenching essentially reta... |

123 |
Heavy quark diffusion in strongly coupled
- Casalderrey-Solana, Teaney
(Show Context)
Citation Context ...5 4 ] √2λ pi 32T 3 (1.1) A different approach chooses to compute the drag force acting a string whose UV end-point (representing an infinitely heavy quark) is forced to move with constant velocity v, =-=[21, 22, 23]-=-, in the context of N = 4 SYM plasma. The result for the drag force is Fconformal = pi 2 √ λ T 2 v√ 1− v2 (1.2) and is calculated by first studying the equilibrium configuration of the appropriate str... |

115 | Exploring improved holographic theories for QCD: Part I”,
- Gürsoy, Kiritsis
- 2008
(Show Context)
Citation Context ...tions of motion are not respected. Similar remarks hold for other phenomenologically interesting observables as the drag force and the jet quenching parameter. A hybrid approach has been advocated in =-=[38, 39, 40]-=- combining features of bottom-up and top-down (string theory) models. Such an approach is essentially a five-dimensional dilaton-gravity system with a non-trivial dilaton potential. Flavor can be even... |

104 | Drag force in AdS/CFT,” Phys - Gubser - 2006 |

102 |
Experimental and theoretical challenges in the search for the quark-gluon plasma: the STAR collaboration’s critical assessment of the evidence from RHIC collisions,"
- Hallman, Adams, et al.
- 2005
(Show Context)
Citation Context ...e UV asymptotics of the integral (5.21) 55 – 1 – References 56 1. Introduction A novel window in the physics of the strong interactions has been provided recently by the experimental efforts at RHIC, =-=[1]-=- . The consensus on the existing data is that shortly after the collision, a ball of quark-gluon plasma (QGP) forms that is at thermal equilibrium, and subsequently expands until its temperature falls... |

84 | Relativistic viscous hydrodynamics, conformal invariance, and holography,” JHEP 0804
- Baier, Romatschke, et al.
- 2008
(Show Context)
Citation Context ...e 1 ≤ T Tc ≤ 3 the QGP seems not to be a 1These are the leading transport coefficients in the derivative expansion. There are subleading coefficients that have been calculated recently for N = 4 SYM, =-=[6]-=-. However, at the present level of accuracy, they cannot affect substantially the comparison to experimental data, [2]. – 2 – fully conformal fluid. Therefore the bulk viscosity may play a role near t... |

81 | Chiral symmetry breaking as open string tachyon condensation,” arXiv:hep-th/0702155. - Casero, Kiritsis, et al. - 2007 |

78 |
Non-critical holography and four-dimensional CFT’s with fundamentals
- Bigazzi, Casero, et al.
(Show Context)
Citation Context ...r the temperature range that is accessible by lattice techniques. The same model also shows a good agreement with the lattice calculation of glue3D4−D4 brane pairs for flavor where first suggested in =-=[42]-=- and the finite temperature solutions studied in [43]. 4Similar results, but with somewhat different potentials were also obtained in [46, 47]. – 5 – ball mass ratios at zero temperature. Moreover the... |

78 |
Mesons in gauge/gravity duals,”
- Erdmenger, Evans, et al.
- 2008
(Show Context)
Citation Context ... mesons. Branes associated to heavy quarks, will fuse outside the horizon, signaling the stability of the associated mesons. These expectations are qualitative. They have been observed in toy models, =-=[68]-=- but have not been yet calculated in a reliable extension of the present setup, [69]. Our estimate is that the bare quark mass is related to the flavor brane position rm in the following way: The ener... |

76 |
Wilson loops in heavy ion collisions and their calculation in AdS/CFT,” hep-ph/0612168
- Liu, Rajagopal, et al.
(Show Context)
Citation Context ...d τ = 6.3 fm. Generally the numbers we obtain are close to those obtained by [17] and [25]. Jet Quenching: We have also calculated the jet quenching parameter of this model, based on the formalism of =-=[19, 20]-=- by computing the appropriate light-like Wilson loop. We find that q̂ grows with temperature, but slower than the T 3 growth of N = 4 SYM result. Again this can be attributed to the incorporation of a... |

74 | Photon and dilepton production in supersymmetric Yang-Mills plasma. - Huot, Kovtun, et al. - 2006 |

73 |
Transverse Momentum Broadening of a Fast Quark
- Casalderrey-Solana, Teaney
- 2007
(Show Context)
Citation Context ... not need to fix an extra parameter by hand. • There are further limitations on the range of applicability of the drag force and jet-quenching calculations, that have been discussed in the literature =-=[70, 71]-=-. In the drag-force calculation the velocity is limited by the position of the associated flavor brane. In a sense the world-sheet horizon should be kept away from that brane so that standard calculat... |

67 | Momentum fluctuations of heavy quarks in the gauge-string duality
- Gubser
- 2008
(Show Context)
Citation Context ...librium relativistic Boltzmann distribution, provides an Einstein relation that is pathological at large temperatures. Second, the transverse and longitudinal diffusion coefficients are not the same, =-=[28]-=-. A first derivation of such Langevin dynamics from holography was given in [28]. This has been extended in in [31] where the thermal-like noise was associated and interpreted in terms of the world-sh... |

65 | Q anti-Q potential from strings in curved space-time: Classical results,” Nucl.Phys. B566 (2000) 103–125, arXiv:hep-th/9811192 [hep-th - Kinar, Schreiber, et al. |

59 | Conformal Relativistic Viscous Hydrodynamics: Applications to RHIC results at √ (sNN
- Luzum, Romatschke
(Show Context)
Citation Context ...t thermal equilibrium, and subsequently expands until its temperature falls below the QCD transition (or crossover) where it finally hadronizes. Relativistic hydrodynamics describes very well the QGP =-=[2, 3]-=-, with a shear-viscosity to entropy density ratio close to the universal value suggested by the holographic formulation of N = 4 SYM, [4]. The QGP is at strong coupling, and it necessitates a treatmen... |

54 | Universal hydrodynamics of non-conformal branes
- Kanitscheider, Skenderis
(Show Context)
Citation Context ...t the bound is proposed to hold in the entire range of temperature from Tc to∞. This bound is trivially satisfied for exact conformal theories such as N = 4 YM, and saturated in theories on Dp branes =-=[57, 58]-=-. With the numerical evaluation at hand, we can check (3.25) in our case. In figure 8 (a) we plot the LHS and RHS of the bound 14. We clearly see that the bound is satisfied for all temperatures. As 1... |

49 | Radiative energy loss of high energy quarks and gluons in a finite-volume quark-gluon plasma
- Baier, Dokshitzer, et al.
- 1997
(Show Context)
Citation Context ...are also expected to play an important role in LHC [15]. A perturbative QCD approach to calculate the energy loss of a heavy quark in the plasma has been pursued by calculating radiative energy loss, =-=[16]-=-. However its application to the RHIC plasma has recently raised problems, based on comparison with data. A phenomenological coefficient used in such cases is known as the jet quenching coefficient q̂... |

48 | How much do heavy quarks thermalize in a heavy ion collision?,” Phys. Rev. C71 - Moore, Teaney - 2005 |

48 |
viscosity of gauge theory plasma at strong coupling, Phys.Lett. B663 (2008) 286-289, arXiv:0708.3459 [hep-th]; A.Buchel, Violation of the holographic bulk viscosity bound
- Buchel
(Show Context)
Citation Context ...l grounds that the de-confinement phase transition happens near this point, i.e. φc ≈ φ∗. Thus, the adiabatic formula predicts that ζ/s(φc) be close to the limit value 1/6pi. 13 3.4 Buchel’s bound In =-=[57]-=-, Buchel proposed a bound for the ratio of the bulk and shear viscosities, motivated by certain well-understood holographic examples. In 4 space-time dimensions the Buchel bound reads, ζ η ≥ 2 ( 1 3 −... |

47 |
Mimicking the QCD equation of state with a dual black hole,” Phys. Rev. D 78, 086007
- Gubser, Nellore
- 2008
(Show Context)
Citation Context ...Λh1.0 1.1 1.2 1.3 1.4 1.5 1.6 ÈcbÈ Figure 5: The coefficient |cb| of equation (3.12) as a function of λh. 3.3 The adiabatic approximation Motivated by the Chamblin-Reall solutions [55], Gubser et al. =-=[56]-=- proposed an approximate adiabatic formula for the speed of sound. In the case when V ′/V is a slowly varying function of φ, [56] proposes the following formulae for the entropy density and the temper... |

42 |
A Calculation of the shear viscosity
- Meyer
(Show Context)
Citation Context ...s opposed to the Ricci tensor of the scalar curvature). In QCD, as the theory is strongly coupled in the temperature range Tc ≤ T ≤ 3Tc, we would expect that η/s ' 14pi . Recent lattice calculations, =-=[7]-=- agree with this expectations although potential systematic errors in lattice calculations of transport coefficients can be large. Conformal invariance forces the bulk viscosity to vanish. Therefore t... |

41 | Thermodynamics of the QCD plasma and the large-N limit”,
- Panero
- 2009
(Show Context)
Citation Context ...are currently pursuing that aim. Note added in proof Since this paper has appeared in the archive, two papers appeared that have a direct connection to some of the issues discussed here. In reference =-=[75]-=- a high precision – 45 – lattice calculation of the thermodynamics was performed at various Nc. The results suggest that the thermodynamic functions vary very little with Nc although the phase transit... |

38 | Finite temperature spectral densities of momentum and R-charge correlators - Teaney - 2006 |

38 |
Stochastic trailing string and Langevin dynamics from AdS/CFT
- Giecold, Iancu, et al.
(Show Context)
Citation Context ...the string. This can be the starting point of a Langevin evolution system, as the process of energy loss has a stochastic character, as was first pointed out in [24] and more recently pursued in [25]-=-=[31]-=-. Such a system involves a classical force, that in this case is the drag force, and a stochastic noise that is taken to be Gaussian and which is characterized by a diffusion coefficient. There are tw... |

38 | Comparing the drag force on heavy quarks
- Gubser
(Show Context)
Citation Context ... of the transport properties mentioned above have been successfully computed in N = 4 SYM and a lot of debate is still waged as to how they can be applied to QCD in the appropriate temperature range, =-=[33]-=-,[34],[35]. A holographic description of QCD has been elusive, and the best we have so far have been simple bottom up models. In the simplest bottom-up holographic model known as AdS/QCD [36], the bul... |

38 | Bulk viscosity of strongly coupled plasmas with holographic duals
- Gubser, Pufu, et al.
(Show Context)
Citation Context ...is technically more involved. For a recent treatment of the fluctuation equation governing the scalar mode of a general Einstein-Dilaton system, see [52]. Here, we shall follow the method proposed by =-=[53]-=-. As explained in [53], one only needs to examine the equations of motion in the gauge r = φ, where the radial coordinate is equal to the dilaton. In our type of metrics, the applicability of this met... |

34 | Energy loss in a strongly coupled thermal medium and the gauge-string duality,” arXiv:0902.4041 [hep-th
- Gubser, Pufu, et al.
(Show Context)
Citation Context ...tom up models. In the simplest bottom-up holographic model known as AdS/QCD [36], the bulk viscosity is zero as conformal invariance is essentially not broken (the stress tensor 2Most are reviewed in =-=[18]-=-. – 4 – is traceless), and the drag force and jet quenching essentially retain their conformal values. In the soft-wall model [37], no reliable calculation can be done for glue correlators and therefo... |

32 | The PHOBOS perspective on discoveries at RHIC, Nucl. Phys. A757 - Back - 2005 |

31 |
Holography of radiation and jet quenching,” Phys
- Sin, Zahed
(Show Context)
Citation Context ...ansport properties mentioned above have been successfully computed in N = 4 SYM and a lot of debate is still waged as to how they can be applied to QCD in the appropriate temperature range, [33],[34],=-=[35]-=-. A holographic description of QCD has been elusive, and the best we have so far have been simple bottom up models. In the simplest bottom-up holographic model known as AdS/QCD [36], the bulk viscosit... |

31 |
Behavior of charmonium systems after deconfinement,
- Datta, Karsch, et al.
- 2004
(Show Context)
Citation Context ...horizon is smaller. An indication that this result may be in the right direction comes from the lattice computation of the shift in the position of the quarkonium resonance peak at finite temperature =-=[63]-=-: in the deconfined phase the charmonium peak moves to lower mass at higher temperature. Our result for the medium-induced shift in the constituent quark mass is consistent with these observations. We... |

30 | Physics of Strongly coupled Quark-Gluon Plasma
- Shuryak
(Show Context)
Citation Context ...nsity ratio close to the universal value suggested by the holographic formulation of N = 4 SYM, [4]. The QGP is at strong coupling, and it necessitates a treatment beyond perturbative QCD approaches, =-=[5]-=-. There are several observables that seem to be important in understanding measured features of the collisions. They translate into transport properties of the strongly coupled plasma, and reliable me... |

30 | Dynamic dilatonic domain walls
- Chamblin, Reall
- 1999
(Show Context)
Citation Context ...0.01 0.02 0.03 0.04 Λh1.0 1.1 1.2 1.3 1.4 1.5 1.6 ÈcbÈ Figure 5: The coefficient |cb| of equation (3.12) as a function of λh. 3.3 The adiabatic approximation Motivated by the Chamblin-Reall solutions =-=[55]-=-, Gubser et al. [56] proposed an approximate adiabatic formula for the speed of sound. In the case when V ′/V is a slowly varying function of φ, [56] proposes the following formulae for the entropy de... |

25 |
Black hole evaporation along macroscopic strings,” Phys
- Lawrence, Martinec
- 1994
(Show Context)
Citation Context ...e momentum that is lost by flowing along the string into the horizon: Fdrag = dp1 dt = − 1 2pi`2s g00g11ξ ′ √−g = piξ . (4.14) This can be obtained by considering the world-sheet Noether currents ΠαM =-=[60]-=- and expressing the loss of momentum as ∆P zx1 = ∫ Πr1. This may be evaluated at any value of r, but it is more convenient to evaluate it at r = rs. We finally find that Fdrag = − 1 2pi`2s √ −g00(rs)g... |

24 |
A Calculation of the bulk viscosity
- Meyer
(Show Context)
Citation Context ...ata, [2]. – 2 – fully conformal fluid. Therefore the bulk viscosity may play a role near the phase transition. So far there have been two approaches that have calculated the bulk viscosity in YM/QCD, =-=[8, 9, 10, 11]-=- and have both indicated that the bulk viscosity rises near the phase transition as naive expectation would suggest. The first used the method of sum rules in conjunction with input from Lattice therm... |

23 |
Energy loss and flow of heavy quarks
- Adare, Afanasiev, et al.
- 2007
(Show Context)
Citation Context ...s are of extra importance, as their mass masks some low-energy strong interaction effects, and can be therefore cleaner probes of plasma energy loss. There are important electron observables at RHIC, =-=[14]-=- that can probe heavy-quark energy loss in the strongly coupled quark-gluon plasma. Such observables are also expected to play an important role in LHC [15]. A perturbative QCD approach to calculate t... |

22 | Spectral sum rules for the quark-gluon plasma,” Phys - Romatschke, Son |

22 |
et al., “Glueball spectrum and matrix elements on anisotropic lattices,” Phys
- Chen, Alexandru, et al.
- 2006
(Show Context)
Citation Context ... = 1 2pi`2s e2As,o(r∗) = 1 2pi`2s e2Ao(r∗)λo(r∗) 4/3 , (4.20) – 26 – where r∗ is the point where the zero-temperature string scale factor As,o(r) has a minimum. For a typical value of σc ∼ (440MeV )2 =-=[61]-=- we find `s = 0.15 ` , (4.21) where ` is the radius of the asymptotic AdS space. On the other hand, unlike in N = 4 SYM, in the IHQCD model the value of the coupling λ(rs) in equation (4.17) is not an... |

22 |
D-branes and extended characters
- Fotopoulos, Niarchos, et al.
(Show Context)
Citation Context ... they are expected to fuse signalling chiral symmetry breaking. The configuration in the broken phase involves a space-filling brane that folds on itself and resembles closely the branes described in =-=[67]-=- using Boundary CFT. The bare mass of the associated quarks enters as a source boundary condition on the relevant tachyon field, [41]. The higher the mass the stronger is the tendency on the tachyon t... |

18 |
Bulk viscosity of QCD matter near the critical temperature
- Kharzeev, Tuchin
(Show Context)
Citation Context ...ata, [2]. – 2 – fully conformal fluid. Therefore the bulk viscosity may play a role near the phase transition. So far there have been two approaches that have calculated the bulk viscosity in YM/QCD, =-=[8, 9, 10, 11]-=- and have both indicated that the bulk viscosity rises near the phase transition as naive expectation would suggest. The first used the method of sum rules in conjunction with input from Lattice therm... |

18 |
Universal properties of bulk viscosity near the QCD phase transition,” Phys
- Karsch, Kharzeev, et al.
(Show Context)
Citation Context ...ata, [2]. – 2 – fully conformal fluid. Therefore the bulk viscosity may play a role near the phase transition. So far there have been two approaches that have calculated the bulk viscosity in YM/QCD, =-=[8, 9, 10, 11]-=- and have both indicated that the bulk viscosity rises near the phase transition as naive expectation would suggest. The first used the method of sum rules in conjunction with input from Lattice therm... |

18 | Heavy-quark probes of the quark–gluon plasma and interpretation of recent data taken at the BNL relativistic heavy ion collider, Phys - Hees, Greco, et al. - 2006 |

17 |
Stirring Strongly Coupled Plasma
- Fadafan, Liu, et al.
(Show Context)
Citation Context ... not need to fix an extra parameter by hand. • There are further limitations on the range of applicability of the drag force and jet-quenching calculations, that have been discussed in the literature =-=[70, 71]-=-. In the drag-force calculation the velocity is limited by the position of the associated flavor brane. In a sense the world-sheet horizon should be kept away from that brane so that standard calculat... |

16 |
Diffusion of charmed quark in the quark-gluon plasma,” Phys. Rev. D37
- Svetitsky
- 1988
(Show Context)
Citation Context ... calculating the momentum flowing down the string. This can be the starting point of a Langevin evolution system, as the process of energy loss has a stochastic character, as was first pointed out in =-=[24]-=- and more recently pursued in [25]-[31]. Such a system involves a classical force, that in this case is the drag force, and a stochastic noise that is taken to be Gaussian and which is characterized b... |

16 | and Y.Shi, “Robustness and Infrared Sensitivity of Various Observables
- Liu
(Show Context)
Citation Context ...lthough it increases with temperature, it does so slower than in N = 4 SYM, signaling the effects of asymptotic freedom. This feature is at odds with the robustness observations for the drag force of =-=[72]-=-. Diffusion Time: Based on the drag force calculation we have computed the diffusion times for a heavy external quark. The numerical values we obtain are in agreement with phenomenological models [17]... |

15 | Bulk viscosity and spectral functions - Moore, Saremi - 2008 |

15 |
Theta dependence of SU(N) gauge theories in the presence of a topological term,” Phys
- Vicari, Panagopoulos
(Show Context)
Citation Context ...asymptotically as r4 close to the UV boundary. In the CP-violating sector, the topological vacuum density tr F F̃ has zero expectation value in the deconfined phase, in agreement with lattice results =-=[48]-=- and large-Nc expectations. The analysis performed in [45] was completely general and did not rely on any specific form of the dilaton potential V (λ). A potential with two parameters, was subsequentl... |

14 |
Heavy Quark Diffusion with Relativistic
- Akamatsu, Hatsuda, et al.
(Show Context)
Citation Context ...ological coefficient used in such cases is known as the jet quenching coefficient q̂, and is defined as the rate of change of the average value of transverse momentum square of a probe. Current fits, =-=[14, 17]-=-, indicate that a value of order 10 GeV 2/fm or more is needed to describe the data while perturbative approaches are trustworthy at much lower values. – 3 – Several attempts were made to compute quar... |

14 | Extracting the QGP viscosity from RHIC data - A Status report from viscous hydrodynamics,” J.Phys.G G36 (2009) 064033, arXiv:0812.4274 [nucl-th
- Song, Heinz
(Show Context)
Citation Context .... The values of this function are mildly dependent on temperature, and are between 1.5 and 2, – 23 – the same range of values that were recently considered in the hydrodynamic codes by Heinz and Song =-=[59]-=-. 4. The drag force on strings and heavy quarks We will now consider an (external) heavy quark moving through an infinite volume of gluon plasma with a fixed velocity v at a finite temperature T [21, ... |

13 |
Heavy-quark energy loss and thermalization in a strongly coupled
- Beuf, Marquet, et al.
(Show Context)
Citation Context ...write the diffusion time from eqs. (4.17) and (4.30) as: τ(T, v) = Mq(T ) σc √ 1− v2 ( λo(r∗) λ(rs) )4/3 e2Ao(r∗)−2A(rs), (4.35) 17For a possible field theoretical explanation of this phenomenon, see =-=[62]-=-. – 30 – bc 1 2 3 4 5 T Tc 0.2 0.4 0.6 0.8 1.0 MsHTL M0 Figure 12: Ratios between the thermal mass and the rest mass of the Charm (curve labeled “c”) and Bottom (curve labeled “b” ) quarks, as a funct... |

13 |
Heavy quark diffusion in perturbative QCD at next-to- leading order
- Caron-Huot, Moore
(Show Context)
Citation Context ...e of the Wilson loop configuration near the boundary, but as shown there does not affect the calculation of the jet-quenching parameter. A perturbative calculation at NLO of the diffusion time gives, =-=[74]-=- 1 τpQCD = 8piT 2 3M α2s [− log g + 0.07428 + 1.8869g] (E.2) 23Interestingly, it was argued in [73] that this fits better Quarkonium data than the Cornell potential. – 54 – while for large Nc N = 4 SY... |

12 | Sound mode hydrodynamics from bulk scalar fields,” Physical Review D,
- Springer
- 2009
(Show Context)
Citation Context ...ic computation of the shear viscosity [51], but it is technically more involved. For a recent treatment of the fluctuation equation governing the scalar mode of a general Einstein-Dilaton system, see =-=[52]-=-. Here, we shall follow the method proposed by [53]. As explained in [53], one only needs to examine the equations of motion in the gauge r = φ, where the radial coordinate is equal to the dilaton. In... |

11 |
Heavy quark potentials in some renormalization group revised AdS/QCD models,” Phys
- Zeng
(Show Context)
Citation Context ... a few “stray logs” in several quantities that are calculated from the world-sheet action (instead of the bulk effective action). One of them is the short distance inter-quark potential calculated in =-=[73]-=- which is23 V (r) ∼ (log(rλ)) 4 3 r . Other similar cases appear in this paper, in the two observables that involve the string world-sheet action. The first is the drag-force calculation. The effect o... |

10 |
Thermalization of heavy quarks
- Hees, Rapp
(Show Context)
Citation Context ...down the string. This can be the starting point of a Langevin evolution system, as the process of energy loss has a stochastic character, as was first pointed out in [24] and more recently pursued in =-=[25]-=--[31]. Such a system involves a classical force, that in this case is the drag force, and a stochastic noise that is taken to be Gaussian and which is characterized by a diffusion coefficient. There a... |

10 |
The bulk viscosity of high-temperature QCD
- Arnold, Dogan, et al.
(Show Context)
Citation Context ...esponds to λh > λmin. result to match with the pQCD result, for the same reasons that the shear-viscosityto-entropy ratio does not, [40]. However, the T-dependence is very similar to the pQCD result, =-=[54]-=-: ζ/s ∝ log−2(piT/Λ) log−1 log(piT/Λ) . (3.15) 3.2 Holographic explanation for the rise of ζ/s near Tc and the small blackhole branch With the same numerical methods, one can also compute the ratio ζ/... |

9 |
Viscous hydrodynamic predictions for nuclear collisions at the LHC,
- Luzum, Romatschke
- 2009
(Show Context)
Citation Context ...ce this value is uncertain, below we give our results for a range of temperatures between 200 MeV and 400 MeV. The higher temperatures will be relevant for the LHC ion collision experiments (see e.g. =-=[64]-=-). Based on these considerations, there are different ways of fixing the temperature (see e.g. the recent review [18]): one direct and two alternative schemes (that we call the energy and entropy sche... |

8 |
Improved holographic QCD at finite temperature: Comparison with data,” Nucl
- Gursoy, Kiritsis, et al.
(Show Context)
Citation Context ...e analysis performed in [45] was completely general and did not rely on any specific form of the dilaton potential V (λ). A potential with two parameters, was subsequently chosen to describe YM data, =-=[49]-=-. The (dimensionless) free energy, entropy density, latent heat and speed of sound, obtained on the gravity side by numerical integration of the 5D field equations, were compared with the correspondin... |

6 |
The deconfinement transition in SU(N) gauge theories,” Phys. Lett. B 545 (2002) 197 [ArXiv:hep-lat/0206029
- Lucini, Teper, et al.
- 2005
(Show Context)
Citation Context ...i-phenomenological and therefore contains two phenomenological parameters (apart from the ones expected in YM) that have been fit to data in [49]. Although several lattice data are known at large-Nc, =-=[65]-=-, others are not. In particular, the detailed thermodynamics of large-Nc YM is currently being calculated on the lattice, [66]. Therefore not all relevant input data we used have been computed at larg... |

6 |
Bulk Viscosity and Cavitation
- Rajagopal, Tripuraneni
(Show Context)
Citation Context ...becomes sharper as Nc increases. The thermodynamic functions and in particular the trace-anomaly calculated from the Improved Holographic QCD model [49] match very well the lattice data. In reference =-=[76]-=- a detailed study of the hydrodymamics with a high-viscosity regime was performed. It was found that cavitation ensues for bulk or shear viscosity values a few times the PSS value, thus corroborating ... |

5 |
Dissecting the string theory dual
- Kiritsis
(Show Context)
Citation Context ...tions of motion are not respected. Similar remarks hold for other phenomenologically interesting observables as the drag force and the jet quenching parameter. A hybrid approach has been advocated in =-=[38, 39, 40]-=- combining features of bottom-up and top-down (string theory) models. Such an approach is essentially a five-dimensional dilaton-gravity system with a non-trivial dilaton potential. Flavor can be even... |

5 | Robustness of Sound Speed and Jet Quenching for Gauge/Gravity Models of Hot QCD,” [ArXiv:0903.1458][hep-th
- DeWolfe, Rosen
(Show Context)
Citation Context ...of glue3D4−D4 brane pairs for flavor where first suggested in [42] and the finite temperature solutions studied in [43]. 4Similar results, but with somewhat different potentials were also obtained in =-=[46, 47]-=-. – 5 – ball mass ratios at zero temperature. Moreover the value of the deconfining critical temperature (in units of the lowest glueball mass) was also in good agreement with the lattice results. In ... |

3 |
talk at the “The Extra Strong Quark Gluon Plasma (ESQGP)”, Stony Brook
- Heinz
- 2008
(Show Context)
Citation Context ...ll see in the present work that our findings support a rise of the bulk viscosity near Tc, but the values are much smaller than previously expected. Studies of how this affects hydrodynamics at RHIC, =-=[13]-=- suggest that this implies a small fall in radial and elliptic flow. Another class of interesting experimental observables is associated with quarks, and comes under the label of “jet quenching”. Cent... |

3 | Predictions for the LHC heavy ion programme
- Borghini, Wiedemann
(Show Context)
Citation Context ...are important electron observables at RHIC, [14] that can probe heavy-quark energy loss in the strongly coupled quark-gluon plasma. Such observables are also expected to play an important role in LHC =-=[15]-=-. A perturbative QCD approach to calculate the energy loss of a heavy quark in the plasma has been pursued by calculating radiative energy loss, [16]. However its application to the RHIC plasma has re... |

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private communication
- Panero
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Citation Context ...fit to data in [49]. Although several lattice data are known at large-Nc, [65], others are not. In particular, the detailed thermodynamics of large-Nc YM is currently being calculated on the lattice, =-=[66]-=-. Therefore not all relevant input data we used have been computed at large Nc. In this sense the semi-phenomenological model we are using is positioned somewhere between Nc=3, YM and Nc = ∞ YM. It is... |