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By: Prof. Ming-Chung Chu (The Chinese University of Hong Kong) Ka-Wah Wong

Cooling of a New Born Compact Star with Quantum ChromoDynamics (QCD) Phase Transition (cooling from hot quark star to cold neutron star). By: Prof. Ming-Chung Chu (The Chinese University of Hong Kong) Ka-Wah Wong (The Chinese University of Hong Kong, University of Virginia)

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By: Prof. Ming-Chung Chu (The Chinese University of Hong Kong) Ka-Wah Wong

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  1. Cooling of a New Born Compact Star with Quantum ChromoDynamics (QCD) Phase Transition(cooling from hot quark star to cold neutron star) By: Prof. Ming-Chung Chu (The Chinese University of Hong Kong) Ka-Wah Wong (The Chinese University of Hong Kong, University of Virginia) UVa Research Symposium - February 4th, 2005

  2. Outline of the Presentation • Very Brief Introduction of Compact Stars, Quark Matter • Energetic Consideration - Static Properties of Quark Stars (EOS:Perturbative QCD ~ s2) • QCD Phase Transition - Cooling

  3. Compact Star Compact Star White Dwarf - degenerate e pressure (ground state e) - Mass ~ MO - R ~ 1000 km -  ~ 107 g/cm3 Neutron(?) Star - degenerate n pressure (ground state n) - Mass ~ MO - R ~ 10 km -  ~ 1015 g/cm3 Black Hole • normal nuclear matter (e.g. proton, neutron) energy density 0 ~ 2.51 x 1014 g/cm3 . . ~ several 0

  4. q q Strong interaction, S Quark Matter • Gell-Menn 1969 - quarks • Gross, Politzer, Wilczek 1973 – asymptotic freedom in strong interaction (Nobel Prize in Physics 2004) • If the interaction is weak enough => free state • =>New State of Matter: Quark-Gluon Plasma q q density/temperature S weaker

  5. d u d u d u Neutron Proton Phase change under high temperature/density s s u d s d d u u u d s Sea of quark Quark matter (strange matter)

  6. Supernova Cooling Phase Diagram

  7. Outline of the Presentation • Very Brief Introduction of Compact Stars, Quark Matter • Energetic Consideration - Static Properties of Quark Stars (EOS:Perturbative QCD ~ s2) • QCD Phase Transition - Cooling

  8. Energy Consideration Latent Heat = Conversion Energy Econv = MG(QS) - MG(NS) same baryon number

  9. Cold EOS from perturbative Quantum Chromodynamics (pQCD) - S2 [Fraga 2001] (asymptotic freedom)  = 2-3 

  10. () => Pressure, Energy Density, Number Density => EOS, P()

  11. Relativistic Star • Internal structure of a static, isotropic relativistic star: TOV equation

  12. Latent Heat = Econv = MG(QS) - MG(NS) same baryon number Summary of Energy Consideration • Within the uncertainty in EOS, Quark Stars can be unstable compared to Neutron Stars, with conversion energy up to 10^{53} erg (energy is comparable to GRB)

  13. Outline of the Presentation • Very Brief Introduction of Compact Stars, Quark Matter • Energetic Consideration - Static Properties of Quark Stars (EOS:Perturbative QCD ~ s2) • QCD Phase Transition - Cooling

  14. T t Cooling • Quark StarNeutron Star Phase Transition Temperature (Tp??) QS (40MeV) Mixed Phase Latent Heat (Econv) Econv = MG(QS) - MG(NS) NS same MB Econv can be ~ 1053 erg! (1 Solar Mass ~ 1054 erg) (Note:GRB release energy ~ 1052 -1054 erg within 0.1-1000s)

  15.   Cq, T  e-e+   Cooling of Bare Quark Star • Assumption: Uniform Temp. ( conductivity) Cq: heat capacity Lq: total luminosity e.g. L, Lblackbody … Ti ~ 40 MeV

  16. Microphysics of Quark Stars • A) Heat capacity: Free Fermi Gas [Iwamoto 1980]

  17. u  P~20 MeV • B) Cooling Mechanisms: a) Thermal Equilibrium Photon Radiation [Alcock 1986]: b) Non-equilibrium q-q Bramstralung Radiation [Chmaj 1991] c/ P~10 fm Low frequency photon ~10-4 Lblackbody

  18. c) Quark URCA Process (Neutrino Emitting) [Iwamoto 1980]

  19. d) e-e+ pair production – fast cooling! [Usov 1997] -- Strong E-field near surface e-e+ 2e)  production – fast cooling! [C.Y.Ng, K.S.Cheng, M.-C.Chu 2001]  q q

  20.  Tcore • Neutron Star Phase Cooling • Standard Cooling Model • Blackbody Radiation • URCA Process () • e-p Columb Scattering • Neutrino Bremstrahung TS   T t

  21. T • Phase Transition t Constant Temperature in the Mixed Phase d n u n s n d n u n n n u s

  22. 2nd Neutrino burst! Tp=1MeV Tp=10MeV temperature photon neutrino Tp=1MeV L ~1053-1047 erg/s for ~105 s L ~1050 at the burst peak

  23. Summary of Phase Transition • Latent heat ~ 1053 erg (GRB energy source?) • L ~ 1048-1054 erg /s, duration ~ 10-3-1000s (or even longer!), short and long GRB?? • Signature 1: 2nd neutrino burst • Signature 2: long duration –ray source

  24. Conclusion • Within the uncertainty based on pQCD, Quark Star can be energetically unstable compared to Neutron Star. • QS NS • 2nd neutrino burst is a signature of PT • Econv is comparable GRB cooling

  25. NEAR THE END

  26. Future Works • More detail understanding of each piece of physics, e.g. EOS, cooling, phase transition process, hydro process, neutrino, high energy phy… • Full simulation from Core Collapse to the formation of Compact Star. • Rotation (Pulsar), Interaction with the environment (SN remnant), Magnetic (Magnetar), SN – SS, SN-GRB-SS relation … • Compare with observation THE END

  27. THE END

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