310 likes | 488 Views
QCD Phase Transition in Dyson-Schwinger Equation Approach. Yuxin Liu Department of Physics, Peking University Beijing 100871, China. Outline I. Introduction II. Brief View of DSE Approach
E N D
QCD Phase Transition in Dyson-Schwinger Equation Approach Yuxin Liu Department of Physics, Peking University Beijing 100871, China Outline I. Introduction II. Brief View of DSE Approach III. Some of Our Work IV. Summary SQM2008,Beijing,China,October 6-10, 2008
I. Introduction The History of the Universe
Aspects influencing QCD P.-T. Medium:Temperature, Density ( or ) Finite size Intrinsic:Current mass, Coupling Str., C-F structure, ••• ••• It relates Confinement – Deconf. S Breaking – Restoration Flavor symmetry breaking Schematic QCD Phase Diagram Chiral Symmetric Quark deconfined sQGP SB, Quark confined
Theoretical Approaches: Lattice QCD Finite Temperature Field Theory, RG, LT with dynamical theory (model): QHD, (p)NJL, QMC, QMF, QSR, INST, DSE, GCM,··· AdS/CFT Key Points: Representing the two main features of QCD: Chiral Symmetry & its Breaking Confinement
II. Brief Description of DSEs in QCD Dyson-Schwinger Equations General Point of View D-S equation is a set of coupled integral eqs. among quark, gluon, ghost and vertex functions, where the n-point function depends on the (n+1)-and higher point functions. C. D. Roberts, et al, Prog. Part. Nucl. Phys. 33 (1994), 477; 45-S1, 1 (2000); EPJ-ST 140(2007,53; R. Alkofer, et. al, Phys. Rept. 353, 281 (2001); .
Quark equation in medium • with Rain-Bow Approximation Quark equation at zero chemical potential where is the effective gluon propagator, can be conventionally decomposed as
Effective Gluon Propagators (1) MN Model (2) (3) (2)Model (3) More Realistic model (4) An Analytical Expression of the Realistic Model: Maris-Tandy Model (5) Point Interaction: (P) NJL Model
Phys. Rev. C 68, 015203 (2003) Example of the success of the DSE: Generation of Dynamical Mass
III. Some of Our Recent WorkEffect of Current Quark Mass on Meson Mass ( L. Chang, Y. X. Liu, C. D. Roberts, et al., Phys. Rev. C 76, 045203 (2007) ) Solving the B-S equation with the kernel being fixed by the solution of DS equation and flavor symmetry breaking, we obtain
(W. Yuan, H. Chen, Y.X. Liu, Phys. Lett. B 637, 69 (2006)) Effect of the running coupling strength on the chiral phase transition parameters are taken From Phys. Rev. D 65, 094026 (1997), with fitted as Lattice QCD result PRD 72, 014507 (2005)
Effect of Current Mass on PT L. Chang, Y. X. Liu, C. D. Roberts, et al, Phys. Rev. C 75, 015201 (2007) (nucl-th/0605058) Solutions of the DSE with Mass function With =0.4 GeV with D = 16 GeV2, 0.4 GeV
Phase Diagram in terms of the Current Mass and the Running Coupling Strength
Distinguishing the Dynamical Breaking from the Explicit Breaking ( L. Chang, Y. X. Liu, C. D. Roberts, et al, Phys. Rev. C 75, 015201 (2007) )
Effect of the chemical potential dependence of the gluon propagator on PT Chiral channel: ( L. Chang, H. Chen, B. Wang, W. Yuan,and Y.X. Liu, Phys. Lett. B 644, 315 (2007) ) Diquark channel: ( W. Yuan, H. Chen, Y.X. Liu, Phys. Lett. B 637, 69 (2006) )
Components of the vacuum of the system with finite isospin chemical potential Case 1., , , ; Case 2. , , , ; Case 3., , , ; Case 4., , ,No Solution. (Z. Zhang, Y.X. Liu, Phys. Rev. C 75, 035201 (2007))
Chiral Susceptibility & PT in NJL Model Y. Zhao, L. Chang, W. Yuan, Y.X. Liu, Eur. Phys. J. C 56, 483 (2008)
Phase Diagram of Quark Matter in P-NJL Model (W.J. Fu, Z. Zhao, Y.X. Liu, Phys. Rev. D 77, 014006 (2008) (2+1 flavor) Simple case: 2-flavor, Z. Zhang, Y.X. Liu, Phys. Rev. C 75, 064910 (2007) ) - relationnucleon properties
Order of the QCD Phase Transitions ( W.J. Fu, Z. Zhao, Y.X. Liu, Phys. Rev. D 77, 014006 (2008) (2+1 flavor) )
Nucleon as a Soliton in DSE B. Wang, H. Chen, L. Chang, & Y. X. Liu, Phys. Rev. C 76, 025201 (2007) Collective Quantization: Nucl. Phys. A790, 593 (2007).
Variation of Nucleon Properties with Respect to the Density of the Matter (L. Chang, Y. X. Liu, H. Guo, Nucl. Phys. A 750, 324 (2005)) - relationnucleon properties
Phase with SB & Confinement is stable hadron matter appears Phase transition from vacuum to matter H. Chen, W. Yuan, L. Chang, YXL, TK, CDR, arXiv:0807.2755
Distinguishing Newly Born SQS From NS NS: RMF, SQS: Bag Model W.J. Fu, H.Q. Wei, and Y.X. Liu, arXiv: 0810.1084, to appear in Phys. Rev. Lett.
IV. Summary We discussed the QCD Phase Transitions ; running coupling strong enough, current mass lower than a critical value,Dynamical chiral symmetry breaking Matter can be generated from vacuum through the chiral phase transitionFundamental & Quite Perspective ! Great efforts are still required !
Three different solutions exist in chiral limit M+ shifts upward too.
Chang, Liu, et al., Phys. Rev C 75, 015201 (2007) M+ shifts upward too.
Shape of Nucleus Sphere Deforemation quadrupole octupole hexadecupole Modes of Nuclear Collective Motion vibration & GR axial rotation ( prolate, oblate) -soft rotation triaxial rotation ••• ••• ••• •••