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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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slide1

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

outline of the presentation
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
slide3

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

quark matter

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

slide5

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)

slide6

Supernova

Cooling

Phase Diagram

outline of the presentation1
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
energy consideration
Energy Consideration

Latent Heat = Conversion Energy

Econv = MG(QS) - MG(NS)

same baryon number

cold eos from perturbative quantum chromodynamics pqcd s 2 fraga 2001
Cold EOS from perturbative Quantum Chromodynamics (pQCD) - S2 [Fraga 2001]

(asymptotic freedom)

 = 2-3 

relativistic star
Relativistic Star
  • Internal structure of a static, isotropic relativistic star: TOV equation
summary of energy consideration

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)
outline of the presentation2
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
slide14

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)

cooling of bare quark star

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

microphysics of quark stars
Microphysics of Quark Stars
  • A) Heat capacity: Free Fermi Gas [Iwamoto 1980]
slide17

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

slide19
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

slide20

Tcore

  • Neutron Star Phase Cooling
  • Standard Cooling Model
  • Blackbody Radiation
  • URCA Process ()
  • e-p Columb Scattering
  • Neutrino Bremstrahung

TS

T

t

slide21

T

  • Phase Transition

t

Constant Temperature

in the Mixed Phase

d

n

u

n

s

n

d

n

u

n

n

n

u

s

slide22

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

summary of phase transition
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
conclusion
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

future works
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