outline: Overview of the Brueckner theory of Nuclear Matter 3BF within the meson-exchange model of the interaction Skyrme-type parametrization of the BHF energy functional In medium Nucleon-Nucleon cross section Transport Parameters and dissipation of collective modes in NS Optical – Model Potential for nucleon-Nucleus collisions at E<200 MeV. NN effective interaction from Brueckner Theory and Applications to Nuclear Systems U. Lombardo Dipartimento di Fisica e Astronomia and INFN-LNS,Catania (It Dynamics and Correlations in Exotic Nuclei YITP, Kyoto 2011
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outline : Overview of the Brueckner theory of Nuclear Matter
Dynamics and Correlations in Exotic Nuclei YITP, Kyoto 2011. NN effective interaction from Brueckner Theory and Applications to Nuclear Systems. U. Lombardo - PowerPoint PPT Presentation
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outline:
Overview of the Brueckner theory of Nuclear Matter 3BF within the meson-exchange model of the interaction Skyrme-type parametrization of the BHF energy functional In medium Nucleon-Nucleon cross section Transport Parameters and dissipation of collective modes in NS Optical – Model Potential for nucleon-Nucleus collisions at E<200 MeV.
NN effective interaction from Brueckner Theory and Applications to Nuclear Systems
U. Lombardo Dipartimento di Fisica e Astronomia and INFN-LNS,Catania (Italy)
Dynamics and Correlations in Exotic Nuclei YITP, Kyoto 2011
Collaboration
M. Baldo, HJ Schulze, INFN CataniaI. Bombaci, Pisa UniversityU. Lombardo, Catania University and INFN-LNSA. Lejeune, Liege University J.F. Mathiot, Clermont-Ferrand,CEAW. Zuo, ZH Li . IMP-CAS, LanzhouH.Q. Song, Fudan University
strongly constrained by the most recent data (few thousands, up to 350 MeV) on NN phase shifts, energy scattering parameters, and deuteron binding energies.
The non-relativistic nuclear many-body problem
ijv
)(1
CoulombnovTHA
i
A
jiiji
Nuclear matter is an homogeneous system made of pointlike protons and neutrons interacting through the Hamiltonian
Nucleon-Nucleon phase shiftsAs an example, Argonne v18 potential :
Wiringa, Stoks, Schiavilla, PRC51, (1995) 38
Due to the short range repulsive core of the NN interaction, standard perturbation theory is not applicable.
,....),()(,...),( 2121 rrrfrr ijji The correlation function f represents the correlations induced by the two-body potential. It is expanded in the same spin-isospin, spin-orbit and tensor operators appearing in the NN interaction.The correlation function is obtained from
From HIC (isoscaling, multigragmentation, n-p products,..) still ambiguous
EoS from BHF : individual contributions and comparison with DBHF
nucleon resonances (F-M) :
Δ(1232),R*(1440)
NN excitations (Z-diagrams)
strong compensation !
The G-matrix expansion (full Brueckner theory) is converging
The non relativistic BHF theory with two body force is consistent with other n.r. many body approaches (e.g., variational method) Including relativistic effects (Z-diagrams) the BHF EoS fully overlaps the DBHF
The three-body force pushes the saturation density to the empirical value, but its effect is small on the saturation energy (1-2 MeV) and compression modulus (220->240 MeV) is small
BHF with 2+3 body force
Ambitious task is to build up a unified EDF for nuclei and nuclear matter:The question is:To what extent a Skyrme-type forces can reproduce the BHF (numerical) EDF as well as experimental observables?
Our hope in such study is to learn what is missing in the theory of nuclear matter and which Skyrme parametrizations cannot match nuclear matter
we performed a ‘weighted fit’ of nuclear matter (theory) and nuclei (experiment) via the Skyrme functional:
reconciling nuclei and nuclear matter
Gambacurta,Li,Colo’,Lombardo, Van Giai,Zuo, PRC 2011
Skyrme-like Energy Functionals (LNSx)
Despite large deviations in the individual spin-isospin components of energy potential U(S,T) large compensation gives rise to similar EoS specially around saturationSince U(S,T) probe different observables (compressibility,symmetry energy, GR’s,…) it looks convenient to fit U(S,T) instead of total USimultaneous Skyrme-like fit of nuclear matter (theory) and nuclei (exp) changing the relative weights:
( ) ( ),
sky skyth thi jST ST i
i j j
w U U w O Oa aa
- + -å å th=BHF Oα = nuclear binding energies and radii.Changing the relative weights we produce different parametrizations: LNSn (n=1,2,3,…)
splitting U into (S,T)
HF calculations from the Skyrme-like parametrizations of BHF theor <- ( LNS1 – LNS5 ) -> exp
closed-shell nuclei b. energy and radii
Sn Isotopic chain
Giant Resonances open problems: tensor and spin-orbit
Energy Density Functional on Microscopic BasisBaldo,Robledo,Schuck,Vinas
finite range term (surface)
Microscopic Transport Equation:
( ) ( ' ' ' ')iji i j i j i j i j i j
j
dI n I n n n n n n n n
d
sæ ö÷ç ÷= = × -ç ÷ç ÷ç Wè øå å %% % %
2
2
pUp pm
e = +
In BHF nuclear potential and cross sections are calculated from G-matrix j
n = 1 - n
Applications:
simulations of heavy ion collisions (test-particle method)from linearization : n = n0 + δn -> collective modes nuclear fluidodynamics: transport parameters in dense matter (high-energy HIC, neutron stars)
Linearizing the Boltzmann equation the connection with phenomenologicaltransport equations is established as well as the transport parameters
( , )Es J is the in-medium NN cross section
medium effects in the cross section:
Pauli blocking (Q): nucleons scatter into unoccupied statesStrong mean field (H0) between two collisions Compression of the level densities in entry and exit chennels
To calculate the cross sections at high density the free scattering amplitude
1( ) ( )T E V V T E
E K= +
-
must be replaced by in-medium scattering amplitude (G-matrix)
( ) ( )Q
G E V V G EE Ho
= +-
In-medium NN cross sections
theoretical framework (G-matrix)
2 2'
*' '
' | | '2 2
f
p ap p
p ppp G pp U
m mt tt
tt t
e<
= + < > = +å å
'
'
*22
2 4
( )| | ( ) | ' |
4 z z
z z
np S
S SSS S
d mp G p
d
s JJ
pá ñ
W å:h
in-medium dσ/dΩ
quasiparticle spectrum
mean free path, viscosity, heat conductivity,…
dσ/dΩ(θ) =N2 |<p|G (θ)|p’ >|2
A) -------------Finite Range Interaction---------------------------
G
N
N
1 *p
FF
d mN
dp p
e-æ ö÷ç ÷= =ç ÷ç ÷çè ø
level density:
effective mass vs ρ
empirical OMP data support theprediction m*n>m*p in ANM
effective mass vs β
In medium effects on the scattering cross section
Mean field and Effective Mass vs β
empirical OMP data support theprediction m*n>m*p in ANM
We expect that in neutron-rich matter. σnn is less suppressed than σpp
θ
pF
Fermi sphereIn CM frame
Δp = 2pF sin (θ/2) =
backward and forward scatterings sizably suppressedby Pauli blocking
A non radial collective excitation of a NS is described by avelocity field
2
0
1 1( ) | |
2
R
i j
dEdV r v
E dth
t=- =- Ñò
η(r )= η(ρ(r)) density profile of NS is required !
Tolman-Oppenheimer-Volkov (TOV) and nuclear EoS
Input Equation of State P=P(, p)
Output Mass-Radius plot
Time scale of nonradial mode damping from shear viscosity
( )( ) 234
3
11 2 1
V
Ml l const
t R Rp
hr
r= - + = =e
Li,Lombardo,Peng, PRC (2008)
tk (s)
0.54 1016
1.5 1016
3.0 1015
6.0 1015
thermal cond.
constant mass approximation
integration over the star (0≤r≤R):r → ρ(r) → η(ρ) → TOV
viscosity time scale
l=2 r-mode
Transition to deconfined phase in neutron stars
Despite the contribution of quarks to viscosity is smaller than hadrons the phase transition is pushing the hadron phase to higher density allowing an extra contribution to viscosity
accompanied by larger frequency and amplitude and then more angular momentum loss for radiation
Since rotating NS exist, GR instability must be stopped bySome damping of Y22 the best candidate is viscosity
1 10
( ) ( )GR c V ct w t w+ =interplay between GR driving instability and viscosity damping
critical velocity:
J0 >> J22 which decreases, being Y22 a sourseof gravitational radiation (General Relativity)
expected to be detected in terrestrial labs ( LIGO,VIRGO,…)
Ω~1000 Hz → τGR ~ 100 sec(depending only on rotation)
1 10
( ) ( )GR c V ct w t w+ =
interplay between GR driving instability and viscosity damping critical velocity:
constant density approximation underestimates the effect of viscosity
Nuclear Potential
Optical Potential vs. nucleon-Nucleus Scattering
( ) ( ( ), ) ( ( ), )U E k E E i k E Eopt R I
1 2
2 2 2 2( , ) ( , ) ( , )
2 2
k kE k E k E k E
m m
mass – shell relation
procedure: for a given approximation of ∑ one solve k=k(E) and determines selfconsistently the on-shell selfenergy
on-shell self.energy
Hughenholtz-Van Hove theorem:0( )AF BE r r= =
BBG hole-line expansion in G-matrix
1 1' | | ' ' | | ' ' | | '
' ' ''' ' ''2 2
U GAU n n pp G pp n pp G pp n n pp ppp p p np A p A p Appp p ppn np p
d d ddd d
= = < > = < > + < >å å åé ùê úê úë û
Nuclear Potential
311 ( )1
p p p
VG G nG G G G G G
n n E n
d rd dd d d
-- -=- =- -
core polarization Dirac sea pol.
3123 2
( )NN bare bare
V V V V V r= + = +å
++ + …
n and p self-energies( , ) ( , ) ( , ) ( , )k E k E k E k Ebhf cpol tbf
p,E
EF
p,E
p,E
EF
EF
Dirac Sea
Evidence for “large” mass ?
Nice et al. ApJ 634, 1242 (2005) PSR J0751+1807 M = 2.1 +/- 0.2
Demorest et al. Nature 467, (2010) J1614-2230 M =1.97 +/- 0.04
Ozel, astro-ph /0605106 EXO 0748 – 676 M > 1.8
Quaintrell et al. A&A 401, 313 (2003) NS in VelaX-1 1.8 < M < 2
ρ ≈ 10 ρ0
OMP Imaginary part:absorption from BHF
from a virtual collisions with the Fermi sea
Im ∑bhf
ε > εF
ε < εF
Im ∑cpol
Im ∑3bf = 0At E>0 Im ∑bhf ≠ 0 only
Which information can be extracted from N-ion collisions? We must first single out the volume contribution from others (surface,spin-orbit,Coulomb)
from NM only the strengthsVv(E,ρn,ρp),Wv(E,)ρn,ρp)
on energy (or momentum ) ,density and isospin
n-A total cross sections
From Koning & Delaroche (NP 2003) parametrization of OMP fitting nucleon-A experimental cross sections one can extract the strength g(E) of the volume component
p-A react.cross sections
( )/
( )( , )
1 e r R avol
g Er E
-=
+V
The strength is energy ,density,and isospin dependent
56Fe + n
--Volume term: real part-- vs. energy
no Coulomb correction
with Coulomb correction
Comparison between BHF and empirical OMP
--Volume term: real part-- vs. asymmetry
28Si
208Pb
--Volume term: real part-- vs. asymmetry
absorption
Volume term (absorption)Vs. asymmetry
Volume term (absorption)vs. energy
theory underestimates empirical dataespecially at high energy
ConclusionsThe Brueckner theory with 3bf makes predictions is consistent with the empirical properties of nuclear matter around the saturation density
The meson-exchange model of the interaction allows to build up the two and threebody force with the same meson parameters adjusted on the experimantal phaseshifts on NN scattering
The NN virtual excitations (Z-diagrams) embody most relativistic effects , making non relativistic BHF comparable with DBHF
Preliminary Skyrme parametrization of the BHF potential energy
The estimate of the time-scale of viscosity dissipation of collective r-modes (with and without deconfined quark phase) is comparable with time-scale ofgravitational waves emission, confirming that the viscosity is the mechanismthat guarantees the stability of rotating NS
The BHF self-energy gives a microscopic basis to the optical-model potential, (volume part) describing nucleon-Nucleus collisions