Theoretical challenges in the physics of nuclei Witold Nazarewicz (Tennessee)

1. Theoretical challenges in the physics of nuclei Witold Nazarewicz (Tennessee) The DNP town meeting on Nuclear Astrophysics/Study of Nuclei Chicago, Jan. 19-21, 2007 • The TM organizers requested to address the following questions: • Identify the major accomplishments in your area since the last long range plan • What has been the impact of this progress within and outside of the field? • Identify the most compelling scientific questions and opportunities for the next decade (within US) and their scientific impact • What facilities and other resources are needed for realizing these opportunities? • A "lower cost" version of an advanced Rare Isotope facility is explicitly mentioned in the charge as the main major new facility for our area compatible with projected funding levels. What role does this facility play in realizing the major future opportunities in the area you are covering? • What other needs does your field have until this new facility is operational? • What will be the scientific impact on other fields, are there interdisciplinary aspects?

2. Input solicited Dec. 18 (RIATG) and Jan. 9 (speakers) • A number of suggestions received Thanks!!! • Other useful sources: • NSAC Theory Report • RIATG Blue Book • RIA Brochure • RISAC report • Various talks, presentations, papers… • Disclaimer: • Not every excellent work/piece of research from 2002-2006 can be highlighted in a 25 min. talk • No pictures, no names (for MANY pictures/names, see Nuclear Theory session) • Only selected/representative references, for the benefit of the writing committee • The focus of this talk is on the questions posed by the Town Meeting Organizers

3. Theory of Nuclei Overarching goal: • Self-bound, two-component quantum many-fermion system • Complicated interaction based on QCD with at least two- and three-nucleon components • We seek to describe the properties of finite and bulk nucleonic matter ranging from the deuteron to neutron stars and nuclear matter; including strange matter • We want to be able to extrapolate to unknown regions To arrive at a comprehensive and unified microscopic description of all nuclei and low-energy reactions from the the basic interactions between the constituent protons and neutrons There is no “one size fits all” theory for nuclei, but all our theoretical approaches need to be linked. We are making great progress in this direction.

4. Weinberg’s Laws of Progress in Theoretical Physics From: “Asymptotic Realms of Physics” (ed. by Guth, Huang, Jaffe, MIT Press, 1983) First Law: “The conservation of Information” (You will get nowhere by churning equations) Second Law: “Do not trust arguments based on the lowest order of perturbation theory” Third Law: “You may use any degrees of freedom you like to describe a physical system, but if you use the wrong ones, you’ll be sorry!” D. Furnstahl, INT Fall’05

5. 2002-2006: very successful period for theory of nuclei • many new ideas leading to new understanding • new theoretical frameworks • exciting developments • high-quality calculations • The nucleon-based description works to <0.5 fm • Effective Field Theory/Renormalization Group provides missing links • Accurate ab-initio methods allow for interaction tests • Quantitative microscopic nuclear structure • Integrating nuclear structure and reactions • High-performance computing continues to revolutionize microscopic nuclear many-body problem: impossible becomes possible

6. Ab initio Configuration interaction Density Functional Theory Roadmap QCDEFT ab-initioeffective many-body methods modern theory of LACM and nuclear reactions Collective and Algebraic Models (top-down) Theoretical approaches overlap and need to be bridged

7. A. Richter, INPC 2004 A cooperative and coherent effort running from QCD through the heaviest nuclei

8. Identify the major accomplishments in your area since the last long range plan I. Science Hard evidence of the progress! • Development of chiral interactions: NN PRC 68, 041001(R)(2003); NNN PRC 66, 064001 (2002) • First fully dynamical lattice QCD calculation of the S-wave NN scattering lengths conducted with pion masses of 350 MeV and larger: PRL 97, 012001 (2006) • Renormalization Group (RG) method used to produce universal low-momentum interactionVlow-k: PRC 70, 061002(R) (2004); Phys. Rep. 386, 1 (2003) • GFMC calculations for 12C and excited states of light nuclei NPA 751, 516c (2005) and EM response in light systems PRC 65, 024002 (2002) • Quantum Monte Carlo description of 1S0 pairing in nuclear matter with NN and NNN: PRL 95,192501 (2005) • No-core Shell Model calculations for light nuclei with chiral NN and NNN forces: PRC 73, 064002 (2006) • Coupled Cluster calculations for light and medium-mass nuclei: PRL 92, 132501 (2004) • Ab-initio description of nuclear reactions; GFMC nucl-th/0612035, NCSM: PRC 73, 065801 (2006); CC: nucl-th/060072 • Explicit RG demonstration that high-energy details in wave functions and operators are irrelevant to low-energy observables: nucl-th/0701013 • Demonstration that conventional nuclear physics explains polarization observables in 4He(e,e’p)3H; no need to modify the proton in nuclear environment: PRL94, 072303 (2005) • Correlations in asymmetric nuclear matter, spectral functions: PRC 71, 014313 (2005); PPNP 52, 377 (2004) • Global Shell Model description of pf nuclei: PRC 69, 034335 (2004) • Unification of structure and reactions - development of modern continuum SM approaches; GSM PRL 89, 042502 (2002); CSM PRL 94, 052501 (2005); SMEC NPA 767, 13 (2006)

9. Science accomplishments (cont.) • Towards universal nuclear density functional • Microscopic DFT mass table: PRC 66, 024326 (2002),PRC 68, 054312 (2003) • Constraints on time-odd fields: PRC 65, 054322 (2002) • Microscopic (GCM+proj) zero-point correlation energies and 2+ states: PRC 73, 034322 (2006); nucl-th/0611089; Gogny+CSE: nucl-th/0701037 • Isovector effective mass: PRC 74 044315 (2006) • Demonstration that the tensor force explicitly impacts shell structure at large isospins: PRL 95, 232502 (2005) • Low-energy strength in exotic nuclei within DFT+QRPA (pygmy and exotic modes): PRC 74, 044301 (2006); PRC 73, 024312 (2006) • Towards microscopic theory of LACM • Projected HFB+GCM description of coexistence phenomena: PRC 69, 064303 (2004) • Fission theory; 5D micro-macro barriers: PRL 92, 072501 (2004); HFB+TDSE: PRC 71, 024316 (2005) • Time-dependent approaches to nuclear fusion; 3D TDHF PRC 73, 054607 (2006); TDSE PLB 637, 53 (2006) • Algebraic description of phase transitions; critical point symmetries: PRL 91, 132502 (2003) • Multistep reactions theory using coupled discretized continuum channels: PRC 65, 024606 (2002) • Determination of spectroscopic factors using ANC PRC 72, 017602 (2005) • Isospin dependence of real and imaginary potentials: PRL 97, 162503 (2006) • Structure of hypernuclei:(SM) NPA 754, 48c (2005); (DFT) NPN 15, 5 (2005)

10. Impact within and outside of the field A. Within Hard evidence of the impact! • Physics of nuclei (guiding experimental programs, see talks by Casten, Macchiavelli, Glasmacher, de Jager) • Can a bound tetraneutron exist?: PRL 90, 252501 (2003) • Analysis of parity-violating electron scattering and proton neutral weak axial form factor: PRL 92, 102003 (2004) • NCSM demonstration of importance of NNN forces in spectroscopy: PRC 68, 034305 (2003) • Nuclear level densities (high-T AFMC shell model): PRC 68, 044322 (2003) • Shell structure of neutron-rich nuclei: PRC 71, 041302 (2005); Phys.Rev. C 66, 054313 (2002) • Predictions of nuclear chiral rotations: Phys. Scr. T125, 1 (2006); PRC 73, 054308 (2006) • Structure of the heaviest and superheavy nuclei: Nature, 433, 705 (2005); PRC 67, 024309 (2003) • Astrophysics (see talks by Truran, Lattimer, Wiescher, Blackmon) • Radiative and weak capture reactions at very low energies (GFMC): NPA 777, 111 (2006) • Superscaling and high-energy -nucleus scattering: PRC73, 035503 (2006); PRL 95, 252502 (2005) • Implementing nuclear physics in supernova models (SM, RPA): PRL 91, 201102 (2003) • Studies of nuclear fusion in dense matter [astrophysics] PRC 72, 025806 (2005) • Neutron stars • Neutron star crust structure (DFT): NPA 719, 217c (2003) • Neutron stars, EOS and neutron skin: Ap. J. 593, 463 (2003) • Pairing, phase transitions and cooling: PRL 92, 082501 (2004); RMP 75, 607 (2003) • Nucleosynthesis (SM, DFT): NPA 752, 560 (2005) • Applications of ANC technique to important transfer reactionsPRC. 67, 6580 (2003) • Fundamental interactions (see talk by Ramsey-Musolf) • Schiff moment of 225Ra (DFT): PRL 94, 232502 (2005) • Neutrinoless double beta decay (SM, QRPA): hep-ph/0611243

11. Impact within and outside of the field B. intersections ! • Dilute Fermions with large/infinite scattering length [impact in nuclear, cold-atom physics, condensed matter and astrophysics (neutron star crust, cooling)] PRL 91, 050401 (2003) 172 citations • EOS, pairing gap near unitarity predicted at T=0 and T>0 PRL 96, 090404 (2006) 43 citations • DFT description: PRA 74, 041602(R) (2006) • EFT/RG treatment of cold atoms: cond-mat/0606069 • Pairing in asymmetric Fermi gasses: PRL 97, 020402 (2006) • Coupled cluster theory, method of moments [impact in nuclear physics and quantum chemistry] PRL 92, 132501 (2004) • DMRG approach to nuclei and open quantum systems Rep. Prog. Phys. 67, 513 (2004) • Description of weakly-bound and unbound states of many-Fermion systems PRL 97, 110603 (2006) • Shell model with random interactions [quantum chaos,quantum dots] PRL 93, 132503 (2004); PRB 72, 045318 (2005); PRB 74, 165333 (2006) • Quantum phase transitions in mesoscopic systems [impact in nuclear, cold-atom, molecular physics] PRL 92, 212501 (2004); NPA 757, 360 (2005) • Applications of SM and DFT to atomic physics: PRA66, 062505 (2002) • Pairing correlations in ultra-small metallic grains (studies of the static-to-dynamic crossover): RMP 76, 643 (2004)

12. Identify the major accomplishments in your area since the last long range plan II. Community http://www.orau.org/ria/RIATG/ The RIA Theory Group (RIATG) Thank you RIA!!!!!

13. Early 2003 Idea behind RIATG conceived November 2003 First RIATG meeting, Tucson November 2003 NSAC Theory Report March 2004 RIATG Charter approved October 2004 Second RIATG meeting, Chicago September 2005 Blue Book finalized September 2005 Third RIATG meeting, Detroit July 2006 JUSTIPEN launched Nov 2006 UNDEF SciDAC-2 funded (DOE and NNSA) Dec 2006 INCITE award (DOE/SC; 5M processor hours)

14. Accomplishments: summary • Progress in all areas • Splendid prospects • Great Expectations see below…

15. Identify the most compelling scientific questions and opportunities for the next decade (within US) and their scientific impact • Working on a bridge between hadrons and nuclei (e.g., lattice QCD with smaller pion masses; match PT with lattice results) • Developing a stringent framework for in-medium modifications • Realistic Hamiltonian (3-nucleon interaction) describing matter and nuclei • GFMC for (i) stable excited states in 12C, A=11 nuclei, unnatural-parity states in A=9,10 and states outside p-shell such as second 0+ in 12C; (ii) scattering states in He and Li nuclei • Studies electroweak observables, including low energy radiative captures, form factors, weak transitions, etc., with the aim of constructing a "realistic" nuclear electroweak current • Studies of correlations via (e,e'p) and (e,e'pN) reactions • Removing “model” from shell model: Applications of NCSM with NN+NNN(+NNNN) chiral EFT forces to light nuclei (structure, reactions/RGM/GSM); help in determining NNN LECs; NCSM in a symplectic basis • Bridging light and heavy: applications of CC theory with NN and NNN forces to halos, unbound states, and A=40-100 • Bridging structure and reactions: advanced GSM, CSM calculations for complex open nuclei, including halo systems; development of realistic interactions.

16. Opportunities (cont.) • Development of realistic nuclear energy density functional (rms error on masses < 500 keV) • Microscopic foundations of NDFT (EFT+RG, SM, ab-initio) • Understanding of density dependence, time-odd fields, effective mass, correlations • Firm analysis of uncertainties • Applications of modern adiabatic and time-dependent theories of LACM to coexistence, fusion, fission; tests of non-adiabatic approaches • Bridging micro and macro: microscopic foundation of symmetry-dictated approaches (predictability added!) • EOS fully characterized at low to moderate densities • Superfluid gaps in nuclear matter pinned down with calculations tied to experimental results in cold atoms and elsewhere; Pairing in asymmetric systems (neutron-proton pairing, polarized cold atoms, and exotic states in nuclei) • Isospin dependence of low- and high-frequency multipole/spin-isospin strength (E1 and GT in particular) • Convergent treatment of many-body continuum • Theoretical justification of surrogate reactions, such as (d,p) • Quantum multi-step excitations in nucleon-nucleus collisions • Microscopic optical potentials and level densities • Time-dependent investigations of the role of neutron skins for heavy ion fusion

17. What will be the scientific impact on other fields, are there interdisciplinary aspects? • Studies of superfluidity in strongly-correlated systems at various density regimes (nuclei, cold atoms, grains, quarks) • AFMC determinations of the level density (tackling the fermionic sign problem) • Applications of nuclear structure models (ab-initio, SM, DFT) to astrophysics (EOS, masses, reaction and decay rates, electroweak capture rates, neutrino propagation in nuclear matter) • Applications of nuclear structure models (ab-initio, SM, DFT) to fundamental interaction/hadronic physics. It is crucial to have reliable estimates of electroweak matrix elements or contaminations from nuclear many-body effects (correlations, two-body currents, etc.). • Applications of nuclear structure models to nanostructures • Study random interaction effects in quantum dots in the presence of spin • Develop a suitable random matrix theory to describe the mesoscopic fluctuations in graphene quantum dots and identify the relevant symmetry classes • Studies of open many-body systems using GSM/CSM (nuclei, atoms and molecules, nanostructures, hadrons) • Studies of quantum phase transitions and phase-transitional behavior

18. Relevance of Nuclear Theory… Addressing national needs • Advanced Fuel Cycles • Workshop in August 2006 identifying needs. • neutron-reaction cross sections from eV to 10 MeV • the full range of (n,f), (n,n’), (n,xn), (n,g) reactions • heavy transuranics, rare actinides, and some light elements (iron, sulfur) • Quantified nuclear theory error bars • Cross sections input to core reactor simulations (via data evaluation) • BETTER CROSS SECTIONS AFFECT both SAFETY and COST of AFC reactors. • Science Based Stockpile Stewardship • Radiochemical analysis from days of testing: inference on device performance shows final products but not how they came to be. • Typical example Yttrium charged particle out reaction. LES THAN 10% of cross sections in region measured. • Theory with quantifiable error bars is needed. These two examples point to the relevance of Nuclear Theory to OTHER programs of national interest. Quantifiable theory error bars is a key desire. Room for large-scale computing (SciDAC) AFC workshop proceedings: www.sc.doe.gov/np/program/docs/AFC_Workshop_Report_FINAL.pdf The Stewardship Science Academic Alliance program workshop: http://www.orau.gov/2007SSAAS/index.htm

19. A "lower cost" version of an advanced Rare Isotope facility is explicitly mentioned in the charge as the main major new facility for our area compatible with projected funding levels. What role does this facility play in realizing the major future opportunities in the area you are covering? • RIA-lite is crucial for theory • The unique data • A unifier • From the RIATG Manifesto… • A unified and consistent approach to nuclear structure phenomena (general) • Nuclei at the extremes of the nuclear chart can magnify important features of the nuclear many-body problem and principal uncertainties of the theoretical description (RIA specific) • Spectroscopy of exotic systems will be an invaluable source of information to learn more about up to now poorly known channels of the shell-model interactions and energy density functionals (RIA specific) also: RIA Brochure, RISAC Report…

20. Postdoctoral prize fellowships Graduate fellowship program Enhanced OJI awards Topical centers Centers of excellence Large scale computing initiatives Elimination of NSF/DOE disparity Increased use of bridge funding Leveraged support for sabbaticals What facilities and other resources are needed for realizing these opportunities? What other needs does your field have until the new RNB facility is operational? Progress since the 2002 LRP and “A Vision for Nuclear Theory” (B. Mueller) Under active consideration for FY07 Considered in broader context (Education Report) Positive response Unrequested proposals submitted to DOE; under consideration Currently dormant Happened Aim in 50% growth in funding Agency positive to bridging opportunities Currently dormant • Need data for calibration and testing! • (to keep theory - and experiment - honest) • LENP facilities and future RIA - for isospin, spin, and mass directions • JLab - for connection to QCD/hadrons, high-k sector, in-medium,…

21. 35% Structure of the nucleon Nuclear structure 21% Hot, dense matter 27% Nuclear astrophysics 10% 2% Fundamental symmetries DOE FY 2006 NP Workforce Survey Results www.sc.doe.gov/production/henp/np/mnpwr/report2006/index.htm DOE Nuclear Theory Support by Subfield (FY05 in k$) + 5% INT

22. Graduate Students, Junior Faculty • Each milestone requires a substantial community of collaborating theorists, with continuing influx of bright young talent ( 20). • 41 milestones (without JLab 12 GeV and RHIC upgrades and without RIA !) require comparable number of theory communities. • 41 x 20 / 2 = 400 (?) Nuclear theory effort must be substantially strengthened and continuously revitalized

23. ENDORSE Instead of conclusions… … a proposal • Possible TM Recommendation • Strongly increase support for theoretical efforts in the areas of nuclear structure, nuclear reactions, and nuclear astrophysics, in concert with an overall increase in nuclear theory as recommended in the 2003 NSAC Theory report.