Neutrino process Neutrino process es es in dense quark in dense quark matter: matter: e e missivity and bulk viscosity missivity and bulk viscosity Qun Wang University of Science and Technology of China Introduction Neutrino emissivity in dense quark matter Bulk viscosity in strange quark matter Discussions and outlooks Strange Quark Matter, Beijing, Oct 6- 10, 2008 • A. Schmitt, I. Shovkovy, QW, PRL 94, 211101(2005) [Erratum: PRL 95, 159902(2005)] • A. Schmitt, I. Shovkovy, QW, PRD 73, 034012(2006) • QW, Z. Wang, J. Wu, PRD 74, 014021 (2006) • X. Huang, QW, P. Zhuang, PRD 76, 094008 (2007) • H. Dong, N. Su, QW, 75, 074016 (2007)
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Neutrino processes in dense quark matter: emissivity and bulk viscosity Qun Wang University of Science and Technology of China Introduction Neutrino.
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Neutrino processNeutrino processeses in dense quark in dense quark matter:matter:eemissivity and bulk viscositymissivity and bulk viscosity
Qun WangUniversity of Science and Technology of China
Introduction Neutrino emissivity in dense quark matter Bulk viscosity in strange quark matter Discussions and outlooks
Strange Quark Matter, Beijing, Oct 6-10, 2008
• A. Schmitt, I. Shovkovy, QW, PRL 94, 211101(2005) [Erratum: PRL 95, 159902(2005)]• A. Schmitt, I. Shovkovy, QW, PRD 73, 034012(2006)• QW, Z. Wang, J. Wu, PRD 74, 014021 (2006)• X. Huang, QW, P. Zhuang, PRD 76, 094008 (2007)• H. Dong, N. Su, QW, 75, 074016 (2007)
Compact Star as LabCompact Star as Lab Mass:Mass:
1.25M1.25M M M 2M 2M
Radius:Radius:RR10 km10 km
Period:Period:1.6 ms1.6 ms P P 12 s 12 s
Core temperature:Core temperature:10 keV10 keV T T 10 MeV 10 MeV
Surface magnetic field:Surface magnetic field:101088 G G B B 10 101414 G G
Overview about neutron stars: Schaffner-Bielich’s talkBlaschke’s talkXu’s talk
Freezeout temperature and chemical potential iFreezeout temperature and chemical potential in n HHeavy eavy IIon on CCollisionsollisions
Physically, bulk viscosity arises from re-equilibration processes. If some quantity goes out of equilibrium on compression, and re-equilibrates on a timescale , then pressure gets out of phase with volume and energy is consumed.
DissipationDissipationA phase lag between density and pressure perturbation
weak interaction
Nature of chemical reaction driven Nature of chemical reaction driven bulk viscositybulk viscosity
Weak processes in bulk viscosityWeak processes in bulk viscosity
• Re-equilibration via
• 2 time scales: external oscillation frequency ω microscopic relaxation time τ
• Volume oscillation → Chemical non-equilibrium
Weak processes in bulk viscosityWeak processes in bulk viscosity
/ ( 0)
d s
u e d
u e s
Chemical equilibrium
Electric charge neutralityEquation of state
3
2 2 322 2
( , ,0
1 1,
)
3
1
3
i i ei
i i i e e
i Bi
Q n n
n m n
n
i u d s
n
Constraints in strange quark matterConstraints in strange quark matter
Baryon number conservationBaryon number conservation
0s
u d
v
v v
New solution respecting new constraints: an extreme case
new constraints
(2 )
( )
3
B u de B
e u d
Bu B
u d
n n n
n n n
n
n n
v v
v v
New solution
Conventional solution
H.Dong, N.Su, Q.Wang PRD 75, 074016 (2007)
Numerical resultsNumerical results
Change of internal energy during a period (heat and particle exchange in current problem are negligible)
Positivity of bulk viscosity in multi-component fluidsPositivity of bulk viscosity in multi-component fluids
Multi-component fluids as an open system locally, with particle exchange
Internal energy work done on system heat transfer particle exchange
period
the i-th cellChen, Dong, QW, in preparation
Positivity of bulk viscosity in multi-component fluidsPositivity of bulk viscosity in multi-component fluids
Chen, Dong, QW, in preparation
Positivity of bulk viscosity in multi-component fluidsPositivity of bulk viscosity in multi-component fluids
Chen, Dong, QW, in preparation
Israel, Stewart, 1976
reproduce coventional results for simple fluid
Summary and conclusionSummary and conclusion
• We have studied neutrino emissions in spin-1 CSC phases and pion condensed quark matter
• Anisotropy in neutrino emission is found in the A-phase of spin-1 CSC
• General constraints on fluid velocity divergences for particles in quark matter are derived from baryon number conservation and enforced electric charge neutrality. A new oscillation pattern in strange quark matter satisfying these conditions is found and its bulk viscosity is calculated
• Positivity of bulk viscosity is proved for multi-component fluid, and a new method for bulk viscosity based on entropy is proposed, which can reproduce coventional results for simple fluid