Hot and dense QCD matter APCTP-WCU Focus Program “ From dense matter to campact stars in QCD and hQCD ”, Pohang, May 24-June 4, 2010 Mei Huang IHEP, CAS TPCSF, CAS

2 Content I.QCD Phase structure chiral restoration & deconfinement phase transition II. Locate CEP from viscosities shear viscosity/entropy density ratio bulk viscosity/entropy density ratio

3 I. QCD Phase Structure

HM QGP CSC HM QGP

5 Compact Star sQGP E. Shuryak, I. Zahed Pseudogap phase Hatsuda,Kunihiro After 2003 High T part

6 After 2003 High density part Abuki-Baym-Hatsuda-Yamamoto, arXiv: Darmstadt and Frankfurt CSC group, Phys.Rev.D72:034004,2005 Many people contributed on the rich structure of CSC APCTP focus program 2006

7 After 2007: Chiral symmetric but confined phase Quarkyonic and half-Skymion phase L. McLerran, R. Pisarski Phase diagram at large Nc Skymion crystal See M. Rho’s talk

8 HM QGP CSC Can Quarkyonic phase be realized in real QCD phase diagram? Fukushima, Hatsuda, arXiv: HM QGP CSC

9 Quarkyonic phase in PNJL model Different choices of Polyakov potential: fixed by lattice QCD at finite T

10 Kenji Fukushima, arXiv:

11 Quarkyonic phase in PLSM model H. Mao, J. Jin, MH, arXiv:

12 In PNJL or PLSM model, at zero baryon density, whether chiral phase transition and deconfinement phase transition coincide or not depends much on parameters used. In these models, there are no interplay between chiral phase transition and deconfinement phase transition.

13 Lattice results on Tc at zero mu Chiral limit: coincide Physical quark mass (2+1): RBC-Bielefeld: coincide Wuppertal-Budapest: (crossover feature)

14 An equivalent order parameter for deconfinement phase transition: Gattringer,PRL97(2006) Bilgici et.al. PRD77(2008) Braun, Hass,Marhauser,Pawlowski, arXiv: Order parameter of center symmetry Confinement: center symmetry Deconfinement: center symmetry breaking

15 The periodicity property of the quark fields change under the the gauge transformation Uz: Dual observables:

16 n=1: dressed Polyakov loop Dual quark condensate: order parameter of center symmetry Dressed Polyakov loop in NJL model

17 Chiral limit: coincide T.Mukherjee, H.Chen,M.Huang, arXiv:

18 T.Mukherjee, H.Chen,M.Huang, arXiv: Physical quark mass: crossover region 1st order:

19 Why for 1 st and 2 nd phase transition? T.Mukherjee, H.Chen,M.Huang, arXiv:

20 Why for crossover? T.Mukherjee, H.Chen,M.Huang, arXiv:

21 Mass effect Nf=2+1 in NJL model is in progress

22 II. Locate CEP by viscosities shear viscosity/bulk viscosity

23 Relativistic Heavy Ion Collision Discovery of “Perfect fluid” at RHIC Hydrodynamics ???

24 A little bit Hydrodynamics

25 Increase shear viscosity reduces elliptic flow! P. Romatschke, U. Romatschke, nucl-th/ Before 2003, people believed that de-confined QCD matter would be weakly coupled gas. Therefore, bulk viscosity is neglected, only consider shear viscosity corrections to the ideal hydro.

26 Discovery of sQGP at RHIC Low shear viscosity

27 Handling strongly coupled system by using AdS/CFT Minimum bound?

28 sQGP: Most “perfect fluid” known Lattice: Nakamura-Sakai(2004) Meyer (2007) Water Policastro, Son, and Starinets; Kovton, Son and Starinets; Buchel, J. Liu; Nakamura, Sin; Maeda, Natsuume, Okamura; …… N =4 SYM : RHIC: Teaney (2003) Romatschke-Romatschke (2007)

29 Interesting global feature of  /s Does  /s make some sense?

30 Phys.Rev.Lett.97:152303,2006 Proposal: Sufficient precise Experimental measurement of  /s to pinpoint the location of phase transitions or crossover. Empirical observation:

31 Lacey et al., PRL 98:092301,2007 Probe CEP by  /s

32 Results from real scalar model Yagi, Hatsuda, Miake, “Quark-Gluon Plasma” Can  /s characterize phase transitions?

33 1, Minimum at Tc, most difficult condition for momentum transportation. 2. The value of  /s at phase transition decreases with increases of coupling strength J.W Chen, MH, Y.H. Li, E. Nakano, D.L.Yang, Phys.Lett.B670:18-21,2008, arXiv:  /s characterizes phase transitions CJT+Boltzmann Eq

Dmitri Kharzeev, Kirill Tuchin arXiv: [hep-ph], F.Karsch, Dmitri Kharzeev, Kirill Tuchin arXiv: [hep-ph], Harvey Meyer arXiv: [hep-ph], However: large bulk viscosity of QCD matter near phase transition Pure gluodynamics 2-flavor case

Bulk viscosity is related to nonconformality Several quantities measure conformality

LQCD results: trace anomaly shows a sharp peak near phase transition BNL-Columbia-RBRC-Bielefeld, arXiv: Bielefeld, hep-lat/

BNL-Columbia-RBRC-Bielefeld arXiv: LQCD results: soft EOS & small sound velocity near phase transition

Gubser et al, AdS/CFT Gravity duals, nonconformal Bulk viscosity in gravity dual models

Results from scalar model: 2nd order phase transition Trace anomaly: height is DOF dependent Baochun Li, Mei Huang, Phys.Rev.D78:117503,2008 arXiv:

EOS & sound velocity Baochun Li, Mei Huang, Phys.Rev.D78:117503,2008 arXiv:

Bulk viscosity/entropy density Baochun Li, Mei Huang, Phys.Rev.D78:117503,2008 arXiv:

42 Results from a more realistic model: PLSM model H. Mao, J. Jin, M. Huang, arXiv: [hep-ph] Comparing with LQCD

43 Sound velocity square at Tc: 0.05 in PLSM, 0.07 in LQCD H. Mao, J. Jin, M. Huang, arXiv: [hep-ph]

44 Comparing with LQCD: Bulk viscosity/entropy density H. Mao, J. Jin, M. Huang, arXiv: [hep-ph]

45 Dependence of bulk viscosity/entropy density on the order of phase transition: large for 1st order phase transition, small for crossover. Thus, bulk viscosity/entropy density is better than shear viscosity/entropy density to probe CEP. H. Mao, J. Jin, M. Huang, arXiv: [hep-ph]

46 Shear viscosity: how much entropy is produced by transformation of shape at constant volume Bulk viscosity: how much entropy is produced by transformation of volume at constant shape Physical quantities related bulk viscosity Generated by translations Generated by dilatations

47 Conclusion and discussion 1, Interplay between chiral phase transition and deconfinement phase transition. 2, Locate CEP by bulk viscosity/entropy density Observables related to bulk viscosity? Radial flow?

48 What’s the effect of large bulk viscosity near Tc? Breakdown of hydrodynamic picture Slow down the expansion of the system Clustering at hadroniztion …… G.Torrieri, B.Tomasik, I.Mishustin, arXiv: [hep-ph] G.Torrieri, I.Mishustin, arXiv: [hep-ph] R.J.Fries, B.Muller,A.Schafer, arXiv: [hep-ph]