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Color Superconductivity: Recent developments. Qun Wang Department of Modern Physics China University of Science and Technology Quark Matter 2006, Shanghai Nov 2006. Outline. Some concepts of CSC Neutrino emissions in CSC BCS-BEC crossover in CSC. QCD: From Paradox to Paradigm.
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Color Superconductivity: Recent developments Qun Wang Department of Modern Physics China University of Science and Technology Quark Matter 2006, Shanghai Nov 2006
Outline • Some concepts of CSC • Neutrino emissions in CSC • BCS-BEC crossover in CSC
QCD: From Paradox to Paradigm David J. GrossH. David PolitzerFrank Wilczek The Nobel Prize in Physics 2004 "for the discovery of asymptotic freedom in the theory of the strong interaction"
Color Confinement Yang-Mills and Mass gap -- A Millenium Problem ($1,000,000) Clay Mathematics Institute -- Officially described by A. Jaffe & E. Witten
DeConfinement: Quark Matter ◆Compress & heat nuclear matter: formation of QM T.D. Lee, 74; Stoecker et al., 74 Collins & Perry, 75 Dense Quark Matter ◆ QM in our Universe ▲Compact Star ▲First few seconds after big bang High-T Quark Matter
Quark Matter in Compact Star F. Weber, astro-ph/007155
Typical energy scale: gap Dissipation free: small perturbation cannot excite system
Spin-zero pairings 2-flavor SC (2SC) Bailin, Love (1984) Color-flavor-locking (CFL) Alford, Rajagopal, Wilczek (1984)
Spin-one pairings Color-spin-locking (CSL) Bailin, Love (1984) Schafer (2000) Polar phase Schafer (2000)
Unconventional pairings Pairings between quarks with non-equal Fermi momenta [See Mei Huang’s talk]
Neutrino processes in quark matter Direct Urca fast Modified-Urca slow
Neutrino processes in quark matter Bremstrahlung slow
Cooling curve for NS F. Weber, 2005; Prakash’s Talk
Phase space for Urca [ Iwamoto 1984 ] [ QW, Wang and Wu, PRD 2006 ] Fermi liquid properties open up phase space for neutrino emissions in Urca (valid for normal and super state)
Neutrino emissivity for S=1 CSC • Gaps in S=0 are large leading to slow cooling; [Alford et al, 2005; Anglani et al, 2006] • Normal state: fast cooling; • Gaps in S=1 are small right to describe data. [Schafer, 2000; Schmitt, Wang, Rischke, 2003]
Spatial Asymmetry in neutrino emissions in A phase Schmitt, Shovkovy, Wang PRL(2005)
Neutrino emissivity in S=1 phases Asymptotic form Schmitt, Shovkovy, QW, PRD(2005) QW, Wang and Wu, PRD(2006)
Science Superfluids:Weak and Strong Couplings BEC, strong couplings BCS, weak couplings
BCS-BEC crossover in relativistic superfluids: fermion-boson model fermions NJL models: Nishida, Abuki, 2005 Abuki, 2006 Bosons: di-fermions
Results: T=0 BCS-BEC crossover parameter A type of scattering length
Results: at unitary limit Unitary limit x=0: In agreement with results of cold atomic system: Physics at unitary limit independent of details of interactions Cold atomic system: Carlson, Reddy, 2005; Nishida, Son, 2006; Rupak, Schafer, Kryjevski, 2006
Summary • CSC is a developing area in particle and nuclear physics • Driven by recent findings at RHIC, strongly coupled CSC will be the next direction to go • Searching for signals of CSC in compact star and high baryon region in heavy ion collisions are the future goal [Randup’s talk], but it is as challenging as to pin down QGP