1. Phase Transitions and the Perfectness of Fluids Jiunn-Wei Chen National Taiwan U.

2. Review: shear viscosity, and the minimum bound conjecture QCD shear viscosity in the hadronic phase: (a) zero density (w/ Eiji Nakano) (b) nuclear L-G phase transition ( w/ Yen-Fu Liu, Yen-Han Li, Eiji Nakano ) Scalar field theory ( w/ Mei Huang, Yen-Han Li, Eiji Nakano, Di-Lun Yang ) Bulk Viscosity ( w/ Juven Wang )

3. Shear viscosity Frictional force

4. Shear viscosity measures how “perfect” a fluid is!

5. Kovtun, Son, and Starinets (’05) Conjecture: Shear viscosity / entropy density Motivated by AdS/CFT

7. QGP (quark gluon plasma) almost saturates the bound @ just above Tc --- a perfect fluid (Teaney; Romatschke, Romatschke; Song, Heinz ), SQGP LQCD, gluon pasma (Karsch, Wyld; Nakamura, Sakai; Meyer) What happens below Tc?

8. QCD Phase Diagram

9. Pion gas ChPT (chiral perturbation theory) Non-perturbative in coupling Boltzman equation

10. JWC, Nakano

11. QCD Phase Diagram

13. The Landscape JWC, Li, Liu, Nakano

15. QCD Phase Diagram

16. Lacey et al., PRL 98:092301,2007 Cold Unitary Atoms Rupak & Schafer 2007

17. of Water (Lacey et al.)

18. 2nd-order p.t.: a 0, c = 0 crossover: + No p.t.: a > 0, b > 0, c = 0 1st-order phase transition a > 0, b 0 (JWC, M. Huang, Y.H. Li, E. Nakana, D.L. Yang)

19. Boltzmann? CJT formulism (Cornwall, Jackiw, Tomboulis) Mean field calculation

22. f Just one minimum (a < 0)? O(N) model? Large b?

24. w/o flavor changing Invading the bound (I) (KSS; Cohen; Cherman, Cohen, Hohler)

25. Invading the bound (II) (T. Cohen)

27. Invading the bound (III) Higher derivative gravity ( Brigante, Liu, Myers, Shenker, Yaida; Kats, Petrov ): O(1/N) effect could invade the bound. Could the bound be saved by some consistency requirement (e.g. stability)?

28. QCD Bulk Viscosity Karsch, Kharzeev, Tuchin; Meyer; JWC, Wang

29. Outlook Universal and behaviors? ( reaches local minimum near p.t. reaches local maximum near p.t.) Mapping QCD phase diagram by Locating critical end point (Lacey)

30. QCD Phase Diagram Probing critical end point by (Lacey)

31. Outlook just below Tc for YM

32. Question Which shear viscosity is bigger? Liquid or gas water near 100 degree C at 1 atm?