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Viscosities and QCD Phase Transitions

Viscosities and QCD Phase Transitions. Jiunn-Wei Chen National Taiwan U. QCD Phase Diagram. Elliptic Flow. Figure: H. Meyer. QGP EOS (LQCD) ~ an ideal gas. Karsch hep-lat/0106019. Elliptic Flow: QGP ~ a strongly interacting fluid. Luzum, Romatschke, 2008.

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Viscosities and QCD Phase Transitions

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  1. Viscosities and QCD Phase Transitions Jiunn-Wei Chen National Taiwan U.

  2. QCD Phase Diagram

  3. Elliptic Flow Figure: H. Meyer

  4. QGP EOS (LQCD) ~ an ideal gas Karsch hep-lat/0106019

  5. Elliptic Flow: QGP ~ a strongly interacting fluid Luzum, Romatschke, 2008 Photon elliptic flow: see Fu Ming LIU’s talk Figure: H. Meyer

  6. QGP EOS (LQCD) ~ an ideal gas Karsch hep-lat/0106019

  7. Shear viscosity Frictional force

  8. Shear viscosity measures how “perfect” a fluid is! Smaller shear viscosity implies larger particle interaction!

  9. Kovtun, Son, and Starinets (’05) Conjecture: Shear viscosity / entropy density • Motivated by AdS/CFT (see talks of JUGEAU & YAKHSHIEV, LU & BRODSKY)

  10. “QGP” (quark gluon plasma) almost saturates the bound @ just above Tc (Teaney; Romatschke, Romatschke; Song, Heinz) • LQCD, gluon pasma (Karsch, Wyld; Nakamura, Sakai; Meyer) QGP near Tc, a near perfect fluid, SQGP • PQGP: Asakawa, Bass, Müller; Xu, Greiner

  11. QCD Phase Diagram

  12. Pion gas ChPT (chiral perturbation theory) • Non-perturbative in coupling Boltzman equation Earlier work: Prakash, Prakash, Venugopalan, Welke; Dobado, Llanes-Estrada; Csernai, Kapusta , McLerran NJL: see Shi Jun Mao’s talk

  13. JWC, Nakano

  14. QCD Phase Diagram

  15. QCD Phase Diagram JWC, Li, Liu, Nakano

  16. goes to a local minimum near a phase transition in more than 30 systems with no exception found so far. Cold Unitary Atoms Rupak & Schafer 2007 T0/TF Nuclear liquid-gas Phase transition JWC et al. 2007 Lacey et al., PRL 98:092301,2007; 2007 US Nuclear Science Long Range Plan

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

  18. Weak coupling, Boltzmann eq. • Mean field calculation • CJT formulism (Cornwall, Jackiw, Tomboulis)

  19. of Water (Lacey et al.)

  20. QCD Bulk Viscosity (Chiral Limit) Karsch, Kharzeev, Tuchin; Meyer; JWC, Wang

  21. QCD Bulk Viscosity Karsch, Kharzeev, Tuchin; Meyer; JWC, Wang See also Fernandez-Fraile, Gomez Nicola

  22. Bulk Viscosity Gubser, Nellore, Pufu, Rocha Li, Huang

  23. Outlook I: Universality? Universal and behaviors? ( reaches local minimum near p.t. reaches local maximum near p.t.)

  24. Mapping QCD phase diagram by ? See You ZHOU’s talk Locating critical end point (Lacey)

  25. Outlook II: Invading the Bound Go metastable(T. Cohen)

  26. Outlook Invading the bound(T. Cohen)

  27. Go Finite N • O(1/N) effect, Higher derivative gravity, (Brigante, Liu, Myers, Shenker, Yaida; Kats, Petrov)

  28. Outlook III: Cold AtomsJohn Thomas’ Exps Free expanding w/ an initial angular velocity Damping in the trap T0/TF

  29. Outlook III: Cold Atoms • NR AdS/CFT Cold Unitary Atoms Adams, Balasubramanian, McGreevy; Maldacena, Martelli, Tachikawa; Herzog, Rangamani, Ross, 2008 d = 2 + 1 Not for cold unitary fermions at 2+1 d, where unitary fermi gas is a free gas JWC, Wen, 08

  30. Outlook IV: PQGP still? Gluon viscosity: need gg gg, gg ggg • Xu & Greiner: R23 ~ 7 R22 (PQGP) • Arnold et al.: R23 ~0.1 R22 (SQGP)

  31. Outlook IV: PQGP still? Gluon viscosity: need gg gg, gg ggg • Xu & Greiner: R23 ~7 R22 (PQGP), parton cascade, soft bremss., massless external legs, LPM • Arnold et al.: R23 ~ 0.1 R22 (SQGP), near collinear bremss., massive external legs, Boltzmann Eq. • Chen, Dong, Ohnishi & Wang: soft bremss., massless external legs, LPM, Boltzmann eq., R23 ~(0.3-3.5) R22, sensitive to phase space

  32. QCD Phase Diagram

  33. The “Landscape” JWC, Li, Liu, Nakano; Itakura , Morimatsu, Otomo

  34. The “Landscape” JWC, Li, Liu, Nakano

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