Nuclear forces and their impact on structure, reactions and astrophysics
Dick Furnstahl Ohio State University July, 2013
Lectures for Week 2
M. Chiral EFT 1 (as); χ-symmetry in NN scattering, QCD 2 (rjf) T. Chiral EFT 2 (rjf); Three-nucleon forces 1 (as) W. Renormalization group 1 (rjf); Forces from LQCD (zd) Th. Renormalization group 2 (rjf); Three-nucleon forces 2 (as) F. Many-body overview (rjf); Nuclear forces and electroweak interactions (as) SRG Overview Methods Lattice 3NF Perturbativeness Numerical Outline
SRG leftovers
Overview of nuclear many-body problem
Many-body methods
Nuclear lattice simulations
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice 3NF Perturbativeness Numerical Tjon line revisited
30 Tjon line for NN-only potentials SRG NN-only λ −1 29 SRG NN+NNN ( >1.7 fm ) λ=1.8 λ=1.5 Expt. 28 λ=2.0 λ=2.5 27 He) [MeV] λ 4 =1.2 λ=3.0 ( b E 26 28.4 3 N LO 28.3 25 (500 MeV) 28.2 8.45 8.5 24 7.6 7.8 8 8.2 8.4 8.6 8.8 3 Eb( H) [MeV]
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice 3NF Perturbativeness Numerical Weinberg eigenvalue analysis of convergence 1 1 1 Born Series: T (E) = V + V V + V V V + E H E H E H ··· − 0 − 0 − 0 For fixed E, find (complex) eigenvalues ην(E) [Weinberg] 1 V Γ = η Γ = T (E) Γ = V Γ (1 + η + η2 + ) E H | ν i ν | ν i ⇒ | ν i | ν i ν ν ··· − 0 = T diverges if any η (E) 1 [nucl-th/0602060] ⇒ | ν | ≥ Im η Im η 1 3 3 S0 S1− D1 1 1
−3 −2 −1 1 −3 −2 −1 1 Re η Re η
−1 −1 AV18 CD-Bonn 3 AV18 N LO CD-Bonn −2 −2 3 N LO (500 MeV)
Dick Furnstahl TALENT: Nuclear forces −3 −3 Pauli blocking in nuclear matter increases it even more! at Fermi surface, pairing revealed by η > 1 | ν |
SRG Overview Methods Lattice 3NF Perturbativeness Numerical Lowering the cutoff increases “perturbativeness” Weinberg eigenvalue analysis (repulsive) [nucl-th/0602060]
Im η 1 0 S 1 0 1 S0 −0.2 −3 −2 −1 1 Re η −0.4 (E=0)
−1 -1 ν Λ = 10 fm η −0.6 -1 Λ = 7 fm Argonne v18 -1 Λ = 5 fm 2 -1 N LO-550/600 [19] −2 Λ = 4 fm 3 -1 −0.8 Λ = 3 fm N LO-550/600 [14] -1 3 Λ = 2 fm N LO [13] 3 N LO −1 −3 1.5 2 2.5 3 3.5 4 -1 Λ (fm )
Dick Furnstahl TALENT: Nuclear forces Pauli blocking in nuclear matter increases it even more! at Fermi surface, pairing revealed by η > 1 | ν |
SRG Overview Methods Lattice 3NF Perturbativeness Numerical Lowering the cutoff increases “perturbativeness” Weinberg eigenvalue analysis (repulsive) [nucl-th/0602060]
Im η 3 3 0 S − D 3 3 1 1 1 S1− D1
−3 −2 −1 1 −0.5 Re η
−1 (E=0) −1 ν
-1 η Λ = 10 fm Argonne v -1 18 Λ = 7 fm 2 -1 N LO-550/600 Λ = 5 fm −1.5 3 -1 −2 Λ = 4 fm N LO-550/600 -1 3 Λ = 3 fm N LO [Entem] -1 Λ = 2 fm 3 N LO −2 −3 1.5 2 2.5 3 3.5 4 -1 Λ (fm )
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice 3NF Perturbativeness Numerical Lowering the cutoff increases “perturbativeness” Weinberg eigenvalue analysis (η at 2.22 MeV vs. density) ν −
1 3 S1 with Pauli blocking
0.5 -1 Λ = 4.0 fm
) -1 d Λ = 3.0 fm
(B 0 -1 ν Λ = 2.0 fm η
-0.5
-1
0 0.2 0.4 0.6 0.8 1 1.2 1.4 -1 kF [fm ] Pauli blocking in nuclear matter increases it even more! at Fermi surface, pairing revealed by η > 1 | ν | Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice 3NF Perturbativeness Numerical Comments on computational aspects Although momentum is continuous in principle, in practice represented as discrete (gaussian quadrature) grid:
= ⇒
Calculations become just matrix multiplications! E.g.,
k V k 0 k 0 V k 1 k V k + h | | ih | | i+ = Vii + Vij Vji + 2 2 ( 2 2) h | | i 0 (k k 0 )/m ··· ⇒ ki kj /m ··· Xk − Xj − 100 100 resolution is sufficient for two-body potential × Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice 3NF Perturbativeness Numerical Discretization of integrals = matrices! Momentum-space flow equations⇒ have integrals like:
I(p, q) dk k 2 V (p, k)V (k, q) ≡ Z Introduce gaussian nodes and weights k , w (n = 1, N) { n n} = dk f (k) w f (k ) ⇒ ≈ n n n Z X Then I(p, q) I , where p = k and q = k , and → ij i j I = k 2w V V V V where V = √w k V k w ij n n in nj → in nj ij i i ij j j n n X X e e e p Lets us solve SRG equations, integral equation for phase shift, Schrodinger¨ equation in momentum representation, . . . In practice, N=100 gauss points more than enough for accurate nucleon-nucleon partial waves
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice 3NF Perturbativeness Numerical MATLAB Code for SRG is a direct translation! d The flow equation ds Vs = [[T , Hs], Hs] is solved by discretizing, so it is just matrix multiplication.
If the matrix Vs is converted to a vector by “reshaping”, it can be fed to a differential equation solver, with the right side:
% V_s is a vector of the current potential; convert to square matrix V_s_matrix = reshape(V_s, tot_pts, tot_pts); H_s_matrix = T_matrix + V_s_matrix; % form the Hamiltontian
% Matrix for the right side of the SRG differential equation if (strcmp(evolution,’T’)) rhs_matrix = my_commutator( my_commutator(T_matrix, H_s_matrix), ... H_s_matrix ); elseif (strcmp(evolution,’Wegner’)) rhs_matrix = my_commutator( my_commutator(diag(diag(H_s_matrix)), ... H_s_matrix), H_s_matrix ); [etc.]
% convert the right side matrix to a vector to be returned dVds = reshape(rhs_matrix, tot_pts*tot_pts, 1);
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice 3NF Perturbativeness Numerical Pseudocode for SRG evolution
1 Set up basis (e.g., momentum grid with gaussian quadrature or HO wave functions with Nmax)
2 Calculate (or input) the initial Hamiltonian and Gs matrix elements (including any weight factors)
3 Reshape the right side [[Gs, Hs], Hs] to a vector and pass it to a coupled differential equation solver 1/4 4 Integrate Vs to desired s (or λ = s− )
5 Diagonalize Hs with standard symmetric eigensolver = energies and eigenvectors ⇒ (i) (i) 6 Form U = ψ ψ from the eigenvectors i | s ih s=0| 7 Output or plotP or calculate observables
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice 3NF Perturbativeness Numerical Many versions of SRG codes are in use
Mathematica, MATLAB, Python, C++, Fortran-90 Instructive computational project for undergraduates! Once there are discretized matrices, the solver is the same with any size basis in any number of dimensions! Still the same solution code for a many-particle basis Any basis can be used For 3NF, harmonic oscillators, discretized partial-wave momentum, and hyperspherical harmonics are available An accurate 3NF evolution in HO basis takes 20 million ∼ matrix elements = that many differential equations ⇒
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice Outline
SRG leftovers
Overview of nuclear many-body problem
Many-body methods
Nuclear lattice simulations
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice Low-energy playground: Table of the nuclides
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice Overlapping theory methods cover all nuclei
dimension of the problem
Interfaces provide crucial clues
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice
What is “new” about theory methods? (examples) Really an explosion of new things! New methods for theoretical inputs (Hamiltonians and operators) Three-body (and higher) forces (N3LO chiral 3NF, RG methods) New extensions of established microscopic techniques e.g., IT-NCSM, MBPT, Berggren basis, LIT Spectroscopic factors, ANCs, . . . (e.g., with GFMC, CC) New microscopic many-body techniques e.g., Lattice EFT, IM-SRG, NCSM/RGM New analysis methods/philosophy (theory error bars!!) Correlation analysis of energy functionals Power counting, benchmarking, . . . New computational reach (e.g., from SciDAC projects) Better scaling: massively parallel codes, load balancing Improved algorithms: e.g., optimization (POUNDERS)
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice Why do we need so many different methods?
Each method has strengths and limitations dimension of the problem Need to cross-check results Exploit overlapping domains Trade-offs: Superior scaling vs. accuracy or more microscopic or . . . Interfaces provide crucial clues
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice NCSM Outline
SRG leftovers
Overview of nuclear many-body problem
Many-body methods
Nuclear lattice simulations
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice NCSM Fully microscopic (from input NN + NNN) Ab initio theory for light nuclei and uniform matter Ab initio: QMC, NCSM, CC,… (nuclei, neutron droplets, nuclear matter) Input choices: Ab initio input • Accurate forces based on phase shift analysis and few-body data • EFT-based nonlocal chiral NN and !"#$%&'($% NNN potentials )*+,'(% • RG-softened potentials evolved from NN+NNN interactions
! Quantum Monte Carlo -&.*/0"&1*.% (GFMC, lattice EFT) 12C • Direct comparison ! No-Core Shell Model with experiment 14F, 14C • Pseudo-data to ! Coupled-Cluster Techniques inform theory 17F, 48Ca
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice NCSM
Size and sparsity of Hamiltonian matrices [from P. Maris]
DimensionsHamiltonian and sparsity matrices of grow matrices rapidly – with stable basis nuclei size (Nmax) and A = N + Z from combinatorics:
10 10 9 10 8 10 7 10 6 10 4He 5 6Li 10 8Be 4 10B 10 12C 3 16O 10 19F 2 10 23Na
M-scheme basis space dimension 1 27Al 10 0 10 0 2 4 6 8 10 12 14 Nmax
Dick Furnstahl TALENT: Nuclear forces
Many Fermion Dynamics – nuclear physics – p.7/16 Many-Body Hamiltonian matrix
Harmonic oscillator single-particle basis states SRG Overview Methods Lattice NCSM Many-Body basis states: Size and sparsitySlater of Determinants Hamiltonian matrices of single-particle[from P. Maris] states But fortunately there are many zero elements so storage is large but feasible.Construct How can we Many–Body take advantage of Hamiltonian sparsity? matrix
large sparse matrix Eigenvalues: bound state spectrum Eigenvectors: nuclear wavefunctions
Dick Furnstahl TALENT: Nuclear forces
Many Fermion Dynamics – nuclear physics – p.4/16 Dimensions and sparsity of matrices – light neutron-rich nuclei
8He (Z= 2, N= 6) 14Be (Z= 4, N= 10) 18 18 10 10
dimension dimension # nonzero’s NN # nonzero’s NN 15 # nonzero’s NNN 15 10 10 # nonzero’s NNN # nonzero’s NNNN # nonzero’s NNNN # nonzero’s NNNNN # nonzero’s NNNNN # matrix elements # matrix elements 12 12 10 10
9 9 10 10
6 6 10 10 SRG Overview Methods Lattice NCSM
3 3 10 10 Size and sparsity of Hamiltonian matrices [from P. Maris]
0 0 10 10 But0 fortunately there 4 are many zero 8 elementsso 12 storage is large but0246 8 10 basis space truncation N basis space truncation N feasible. How can we take advantagemax of sparsity? max 11Li (Z= 3, N= 8) 20C (Z= 6, N= 14) 18 18 10 10
dimension dimension # nonzero’s NN # nonzero’s NN 15 15 # nonzero’s NNN 10 # nonzero’s NNN 10 # nonzero’s NNNN # nonzero’s NNNN # nonzero’s NNNNN # nonzero’s NNNNN # matrix elements # matrix elements 12 12 10 10
9 9 10 10
6 6 10 10
3 3 10 10
0 0 10 10 0246 8 10 12 0246 8 basis space truncation Nmax basis space truncation Nmax
Dick Furnstahl TALENT: Nuclear forces
Many Fermion Dynamics – nuclear physics – p.8/16 SRG Overview Methods Lattice NCSM Lanczos method in short
Consider an arbitrary vector Ψ and its expansion in eigenstates | i of H, where H ψ = E ψ . Then Hm Ψ = C E m ψ | k i k | k i | i k k k | k i If m large enough, largest E will dominate the sum | k | P = project out the corresponding eigenvector ⇒ To get lowest eigenvalue, use (H σI)m with σ > 0 large − enough so that E σ > E σ | 0 − | | max − | More efficient to diagonalize H in the basis spanned by H ψ , | k i H2 ψ ,..., Hm ψ | k i | k i Called the “Krylov space” Lanczos: orthogonalize basis states as you go, generating H in tri-diagonal form, which is efficiently diagonalized Re-orthonormalization for numerical stability Many computational advantages to treating sparse matrices with Lanczos [see J. Vary et al., arXiv:0907.0209]
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice NCSM !"#$%&'()%*+,-'./01%234(%)'%2'.567%
!"4,'(2CX*-"&(1*4+#0+)*'(*BJKWQD*.+"4*/"#52#05+K* ,%7*'7/+4*#01/7*(%$#+0*%(-+41'*)060#"4*,+7"*-+$".* @07/*/"#52#0>+)*#+))*7/"(*"*-".Y*
•*Z+6,+4)*'5*[9;<\*$'##",'4"&'(*6"-+*60$4')$'30$* ***(%$#+"4*)74%$7%4+*$"#$%#"&'()*7'*)'#>+*7/+*3%]]#+* •*[)+-*).)7+6"&$*$/04"#*^"60#7'(0"(*54'6*#'@2+(+41.* ***+_+$&>+*`+#-*7/+'4.*'5*a!<* •*b+.*5+"7%4+A*$'()0)7+(7* !"#$%&'(#)0(7+4"$&'()*
Q2(%$#+'(*5'4$+)*)%334+))*$40&$"#*$'63'(+(7*$'63"4+-*7'*I2(%$#+'(*5'4$+)*'(#.*
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!"#$%#"&'()*+(",#+-*,.*/01/23+45'46"($+* $'63%&(1*7/4'%1/*89!8:;*34'14"6* ! <06+()0'(*'5*6"740=*)'#>+-*5'4*?*#'@+)7* )7"7+)A**B*C=CDE* ! F'#%&'(*7''G*B*H*/'%4)*'(*ICJKDDD*$'4+)* '(*!4".*L:J*M"1%"4*"7*NO9P*
(+7*-+$".*4"7+** F$0+($+*4+5RA**S/.)0$"#*O+>0+@*P+T+4)*089K*IDIJDI*UIDCCV* 0)*>+4.*)6"##* !'63%7"&'("#*4+5RA**S4'$+-0"*!'63%7+4*F$0+($+*0K*EW*UIDCDV*
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice NCSM ImportanceImportance Truncated Truncated NCSM NCSM [Roth et al.]
Roth, PRC 79, 064324 (2009); PRL 99, 092501 (2007)
I converged NCSM calcula- -110 16 tions essentially restricted O -120 to lower/mid p-shell ] NNonly -130 α 0.04 fm4 MeV I full Nmx 10 calculation [ hΩ 20 MeV = for 16Overydifficult E -140 ̵ = (basis dimension= 1010) -150 . > 0 24681012 14 16 18 20 Importance -110 G Nmx IT-NCSM Truncation -120 full NCSM ] reduce model space -130 + MeV to the relevant basis [
E -140 states using an apriori importance measure -150 derived from MBPT . 0 24681012 14 16 18 20 Nmx Robert Roth – TU Darmstadt – 05/2013 13 Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice NCSM
Coupled cluster method [from D. Dean, G. Hagen, T. Papenbrock] Coupled-cluster method (in CCSD approximation)
! >6$-,#(?,"%-@(A0*-@"*B7$-C(D7%2(7"6+,$#7"?( !"#$%&' ((( 0+*E-,B(#7&,(*4;F(8( ! G+;"6$.*"(7#(%2,(*"-@($00+*57B$.*"8( ! >7&,(,5%,"#7H,(A,++*+(#6$-,#(D7%2(!C( "((I*#%(,J67,"%(:*+(3*;E-@(B$?76(";6-,7(
)*++,-$.*"#($+,(!"#$%!%&'(!)(/01/2($"3(40142(,567%$.*"#8(9$+%(*:("01"2(,567%$.*"#( 7"6-;3,3<( ( ( (
)*;0-,3(6-;#%,+(,=;$.*"#( !"#$%&'()$*)+$,-*../0*1$&$%'#$2*2+3+"'%+#4* ( #%'&256%3$7*8'3+"#6&+'&*,+#9*&6*:;<:9*'&7* &6*=;<=9*$>?+#'(6&2@* ( (
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice NCSM
Coupled cluster method [from D. Dean, G. Hagen, T. Papenbrock] Asymmetry dependence and spectroscopic factors
•!"#$%&'($'")$*+,$%'&(*,*-'%* '.(#&/,.0#(** •12#3*,*#4%&,$%#5*+&'6*,*$&'((* (#$7'-*.,(#5*'-*,*("#$)8$*(%&9$%9* ,-5*,$7'-*6'5#0** •!%&9$%9*,-5*,$7'-*6'5#0(*-##5(* %'*.#*$'-()(%#-%:**
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice NCSM
Coupled cluster method [from D. Dean, G. Hagen, T. Papenbrock] Quenching of spectroscopic factors for proton removal in neutron rich oxygen isotopes
!"#$%&'($'")$*+,$%'&*)(*,*-(#+-.*%''.*%'*(%-/0* $'&.,1'2(*%'3,&/(*%4#*/&)".)2#5** * !6*+'&*"&'%'2*'8,.*)2*2#-%&'2*&)$4*9:;*(4'3* (%&'2<*=>-#2$4)2
!%&'2<*,(077#%&0*/#"#2/#2$#*'2*%4#*!6* +'&*"&'%'2*,2/*2#-%&'2*'8,.*)2* 2#-%&'2*&)$4*'Q0<#2*)('%'"#(5** * !6RI*+'&*2#-%&'2*'8,.*34).#*"&'%'2(* ,*(%&'2<.0*$'&.,%#/*!6*RJ5S@J5K*)2* 99L9:L9T;**
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice NCSM
In-mediumDecoupling SRG decoupling in A-Body[slides Space from H. Hergert]
ConsiderDecoupling SRG with 0p –0inh A-Bodyreference stateSpace (instead of vacuum)
P / Q P / Q
K. Tsukiyama, S. K. Bogner, and A. Schwenk, PRL 106, 222502 (2011)
Dick Furnstahl TALENT: Nuclear forces H. Hergert - Ohio State University - ANL Theory Seminar, 03/22/12
H. Hergert - Ohio State University - ANL Theory Seminar, 03/22/12 SRG Overview Methods Lattice NCSM In-mediumDecoupling SRG decouplingin A-Body[H. Space Hergert]
Aim: decouple reference state (0p–0h) from excitations
0p-0h 1p-1h 2p-2h 3p-3h
1p-1h 0p-0h
= 2p-2h ⇒ 3p-3h
K. Tsukiyama,P / S.Q K. Bogner, and A. Schwenk, PRL 106, 222502 (2011) Dick Furnstahl TALENT: Nuclear forces
H. Hergert - Ohio State University - ANL Theory Seminar, 03/22/12 Results:SRG Oxygen Overview Methods Chain Lattice NCSM
[H. Hergert] Oxygen0 chain with multi-reference0 IM-SRG ÙÊ A A Û NN + 3N-ind. O ÛÙÊ NN + 3N-full (400) O -25 E3 Max=14 -25 E3 Max=14 l=1.9 fm-1 l=1.9 fm-1 ʇ -50 -50 ʇ
D -75 D -75 ÛÙʇ MeV MeV
@ @ Ù‡ -100 -100 ÛÊ E E
exp. Ù‡ -125 ÛÊ -125 ʇ ÛÙʇ ‡ Ê IM-SRG Ê Ê IM-SRG ʇ ‡ ÙÊ ‡ -150 ‡ IT-NCSM Û ‡ -150 ‡ IT-NCSM Ê ÙÊ Ê‡ Ù CCSD Û Ù CCSD Ùʇ Û ‡ ʇ Û L-CCSD T Û L-CCSD T ÙÊ -175 -175 Û 10 12 14 16 18 20 22 24 26 10 12 14 16 18 20 22 24 26 H L A H L A • ref. state: number-projected Hartree-Fock-Bogoliubov vacuum • results (mostly) insensitive to choice of generator for same Hod • consistency between different many-body methods
Scott Bogner - Michigan State University - NUCLEI Collaboration Meeting, Indiana University Bloomington, 06/25/13
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice NM DFT Outline
SRG leftovers
Overview of nuclear many-body problem
Many-body methods
Nuclear lattice simulations
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice NM DFT
Lattice EFT collaboration [E. Epelbaum] NuclearEffective Lattice field theory Effective on the lattice: Field Theory Ab initio calculations of nuclei and many-body systems The Collaboration: E.E., Hermann Krebs (Bochum), Timo Lähde (Jülich), Dean Lee (NC State), Ulf-G. Meißner (Bonn/Jülich), Gautam Rupak (Mississippi State)
!"#$%&'()&**+#%(,-.(/0$$&10'&*+02 Borasoy, E.E., Krebs, Lee, Meißner, Eur. Phys. J. A31 (07) 105, n Eur. Phys. J. A34 (07) 185,Evgeny Epelbaum (Bochum) Eur. Phys. J. A35 (08) 343, Hermann Krebs (Bochum) Eur. Phys. J. A35 (08) 357, p
E.E., Krebs, Lee, Meißner, Eur. Phys. J A40 (09) 199, Timo Lähde (Jülich) 20 fm 1 Eur. Phys. J A41 (09) 125, Dean Lee (NC State) ...
Phys. Rev. Lett 104 (10)Ulf 142501,-G. Meißner (Bonn/Jülich) 10
Eur. Phys. J. 45 (10) 335, ⇠ Phys. Rev. Lett. 106 (11) 192501, TU Darmstadt L E.E., Krebs, Lähde, Lee, Meißner Phys. Rev. Lett. 109 (12) 252501, Phys. Rev. Lett. 110 (13) 112502, Institut für Kernphysik arXiv:1303.4856 May 22, 2012 a 1 ...2fm ⇠
1
Dick Furnstahl TALENT: Nuclear forces
1 SRG Overview Methods Lattice NM DFT
Lattice QCD versus lattice EFT [from Dean Lee]
Compare variables and lattice spacing a:
Lattice effective field theory Lattice quantum chromodynamics
u n d n
p
p n p u
Dick Furnstahl TALENT: Nuclear forces SRG Overview Methods Lattice NM DFT NUCLEAR LATTICE SIMULATIONS 13 Lattice EFT basics [from U. Meißner] Frank, Brockmann (1992), Koonin, Muller,¨ Seki, van Kolck (2000) , Lee, Schafer¨ (2004), ... Borasoy, Krebs, Lee, UGM, Nucl. Phys. A768 (2006) 179; Borasoy, Epelbaum, Krebs, Lee, UGM, Eur. Phys. J. A31 (2007) 105
new method to tackle the nuclear many-body problem • discretize space-time V = L L L L : p • s × s × s × t nucleons are point-like fields on the sites n discretized chiral potential w/ pion exchanges • and contact interactions p
typical lattice parameters n a • π Λ = 300 MeV [UV cutoff] a ~ 2 fm
strong suppression of sign oscillations due to approximate Wigner SU(4) symmetry • J. W. Chen, D. Lee and T. Schafer,¨ Phys. Rev. Lett. 93 (2004) 242302 hybrid Monte Carlo & transfer matrix (similar to LQCD) •
Nuclear Physics from LatticeDick Simulations Furnstahl – Ulf-G. MeißnerTALENT: – EMMI, MayNuclear 10, 2012 forces < > · ◦ ∧ • 14 CONFIGURATIONS SRG Overview Methods Lattice NM DFT
Lattice EFT basics [from U. Meißner]
all possible configurations are sampled ⇒ clustering emerges naturally ⇒
Nuclear Physics from LatticeDick FurnstahlSimulations – Ulf-G.TALENT: Meißner – Nuclear EMMI, May forces 10, 2012 < > · ◦ ∧ • 15 SRG Overview Methods Lattice NM DFT TRANSFER MATRIX METHOD Lattice EFT basics [from U. Meißner] Correlation–function for A nucleons: Z (t)= Ψ exp( tH) Ψ • A A| − | A with ΨA a Slater determinant for A free nucleons Euclidean time
Ground state energy from the time derivative of the correlator • d EA(t)= ln ZA(t) −dt
0 ground state filtered out at large times: E = lim EA(t) A t → →∞
Expectation value of any normal–ordered operator • O
ZO = Ψ exp( tH/2) exp( tH/2) Ψ A A| − O − | A
ZAO(t) lim = ΨA ΨA t →∞ ZA(t) |O |
Nuclear Physics from Lattice Simulations – Ulf-G. Meißner – EMMI, May 10, 2012 < > Dick Furnstahl TALENT: Nuclear forces· ◦ ∧ • SRG Overview Methods Lattice NM DFT 16 TRANSFER MATRIX CALCULATION Lattice EFT basics [from U. Meißner] Expectation value of any normal–ordered operator • O
ΨA exp( tH/2) exp( tH/2) ΨA ΨA ΨA = lim | − O − | |O | t Ψ exp( tH) Ψ →∞ A| − | A Anatomy of the transfer matrix •
operator insertion for expectation value Ψ free SU π O SU π Ψ free Z,N (4) full LO full LO (4) Z,N
L + L L + L L + L L 2 to ti to ti to ti/2 to 0 { { inexpensive filter inexpensive filter
Dick Furnstahl TALENT: Nuclear forces
Nuclear Physics from Lattice Simulations – Ulf-G. Meißner – EMMI, May 10, 2012 < > · ◦ ∧ • SRG Overview Methods Lattice NM DFT 17
LatticeMONTE EFT CARLO basics with AUXILIARY[from U. Meißner] FILEDS
Contact interactions represented by auxiliary fields s, s • I + 2 ∞ 2 exp(ρ /2) ds exp( s /2 sρ) , ρ N †N ∝ − − ∼ −∞ Correlation function = path-integral over pions & auxiliary fields •
S
S ⇒
Nuclear Physics from LatticeDick Simulations Furnstahl – Ulf-G. MeißnerTALENT: – EMMI, Nuclear May 10, forces 2012 < > · ◦ ∧ • SRG Overview Methods Lattice NM DFT 8 12 Ground statesGround of statesBe and ofC 8Be[E. Epelbaum] and 12C E.E., Krebs, Lee, Meißner, PRL 106 (11) 192501 Ground state of Beryllium-8 Ground state of Carbon-12 Simulations for 8Be and 12C, L=11.8 fm
Epelbaum, Krebs, D.L, Meißner, PRL 106 (2011) 192501 Epelbaum, Krebs, D.L, Meißner, PRL 104 (2010) 142501; Ground state energies (L=11.8 fm) of 4EPJAHe, 45 8 (2010)Be, 335; 12C PRL & 106 16 (2011)O 192501 31 33 4He 8Be 12C 16O LO [Q0], in MeV 28.0(3) 57(2) 96(2) 144(4) NLO [Q2], in MeV 24.9(5) 47(2) 77(3) 116(6) NNLO [Q3], in MeV 28.3(6) 55(2) 92(3) 135(6) Experiment, in MeV 28.30 56.5 92.2 127.6
Dick Furnstahl TALENT: Nuclear forces
⇤⇥ ⇤q ⇤⇥ ⇤q V = 1 · 1 3 · 3 ⌧ ⌧ (q )+⌧ ⌧ ⌧ ⇤q ⇤q ⇤⇥ (q ) 2 [q2 + M 2][q2 + M 2] 1 · 3 A 2 1 ⇥ 3 · 2 1 ⇥ 3 · 2 B 2 1 3 ⇣ ⌘
g2 g2 c (3)(q )= A (2c 4c )M 2 + c q2 , (3)(q )= A 4 , A 2 8F 4 3 1 3 2 B 2 8F 4 ⇣ ⌘
g4 (4)(q )= A A(q ) 2M 4 +5M 2q2 +2q4 + 4g2 +1 M 3 +2 g2 +1 M q2 , A 2 256 F 6 2 2 2 A A 2 h ⇣ ⌘ ⇣ ⌘ ⇣ ⌘ i g4 (4)(q )= A A(q ) 4M 2 + q2 +(2g2 +1)M B 2 256 F 6 2 2 A h ⇣ ⌘ i
g (5)(q )= A M 2q2(F 2 2304 2g (4e¯ +2e¯ e¯ e¯ ) 2304 2d¯ c A 2 4608 2F 6 2 A 14 19 22 36 18 3 h ⇣ ⌘ + g (144c 53c 90c )) + M 4 F 2 4608 2d¯ (2c c )+4608 2g (2e¯ +2e¯ e¯ 4e¯ ) A 1 2 3 18 1 3 A 14 19 36 38 ⇣ ⇣ ⌘ + g 72 64 2¯l +1 c 24c 36c + q4 2304 2e¯ F 2g 2g (5c +18c ) A 3 1 2 3 2 14 A A 2 3 ⇣ 2 ⇣ ⌘ ⌘⌘ ⇣ ⌘i gA 2 2 2 2 2 6 L(q2) M +2q2 4M (6c1 c2 3c3)+q2( c2 6c3) , 768 F g ⇣ ⌘⇣ ⌘ (5)(q )= A M 2 F 2 1152 2d¯ c 1152 2g (2e¯ +2e¯ e¯ ) +108g3 c +24g c B 2 2304 2F 6 18 4 A 17 21 37 A 4 A 4 h ⇣ ⇣ ⌘ ⌘ g2 c + q2 5g c 1152 2e¯ F 2g + A 4 L(q ) 4M 2 + q2 2 A 4 17 A 384 2F 6 2 2 ⇣ ⌘i ⇣ ⌘
p⇤1 p⇤10 p⇤2 p⇤20 p⇤3 p⇤30
22 V loc. = F (r ,r ,r )+5perm.. 3N Gi i 12 23 31 Xi=1 =1, = ⌧ ⌧ , = ⇤⇥ ⇤⇥ ,... G1 G2 1 · 2 G3 1 · 3
1 222 ticeticetice spacing spacing spacingaaa=1=1=1.97..9797 fm fm fm and and and total total total length length lengthLLL=== 12 12 12 fm. fm. fm. In In In SRG Overview Methods Lattice NM DFT TABLETABLETABLE I: I: I: Lattice Lattice Lattice results results results and and and experimental experimental experimental values values values for for for the the the thethe time time direction, direction, we we use use lattice lattice time time step stepaat =1=1..3232 fm fm 44 88 the time direction, we use lattice time step att=1.32 fm groundgroundground state state state energies energies energies of of of4HeHeHe and and and8Be.Be.Be. All All All energies energies energies are are are in in in and vary the propagation time L to extrapolate to the Hoyle State [E. Epelbaum] andand vary vary the the propagation propagation time timeLLttttoto extrapolate extrapolate to to the the unitsunitsunits of of of MeV. MeV. MeV. The Hoyle state EE, Krebs,Nuclear Lähde, Physics Lee, withMeißner, Chiral PRL Effective 106 (2011) Field 192501; Theory PRL 109 (2012) 252501 Evgeny Epelbaum limitlimitlimitLLLt ... The The The nucleons nucleons nucleons are are are treated treated treated as as as point-like point-like point-like 444 888 tt ⇥ HeHeHe BeBeBe ⇥ ⇥ 12 particlesparticlesparticles on on on lattice lattice lattice sites, sites, sites, and and and interactions interactions interactions due due due to to to the the the ex- ex- ex- Lattice0 results for low-lying even-parity states of C LOLOLO [O [ [OO((Q(QQ00)])])] 282828.0(3)..0(3)0(3) 57(2)57(2)57(2) changechangechange of of of pions pions pions and and and multi-nucleon multi-nucleon multi-nucleon operators operators operators are are are gener- gener- gener- + + + + + + 1 222 01 21 (E ) 02 22 (E ) atedatedated using using using auxiliary auxiliary auxiliary fields. fields. fields. Lattice Lattice Lattice e e⌅ e⌅⌅ectiveectiveective field field field theory theory theory NLONLONLO [O [ [OO((Q(QQ)])])] 242424.9(5)..9(5)9(5) 47(2)47(2)47(2) LO 3 96(2) 94(2) 89(2) 88(2) was originally used to calculate the many-body proper- NNLONNLONNLO [O [ [OO((Q(QQ33)])])] 282828.3(6)..3(6)3(6) 55(2)55(2)55(2) 0.5 waswas originally originally used used to to calculate calculate the the many-body many-body proper- proper- NLO 77(3) 74(3) 72(3) 70(3) ties of homogeneous nuclear and neutron matter [19, 20]. Experiment 28.30 56.50 tiesties of of homogeneous homogeneous nuclear nuclear and and neutron neutron matter matter [19, [19, 20]. 20]. ExperimentExperimentNNLO 289228(.330.)30 568956.(50.350) 85(3) 83(3) t