Article records
https://feeds.library.caltech.edu/people/Koonin-S-E/article.rss
A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenTue, 16 Apr 2024 13:48:36 +0000A "hybrid" R-matrix-optical model parametrization of the ^(12)C(α, γ)^(16)O cross section
https://resolver.caltech.edu/CaltechAUTHORS:20151106-135750173
Authors: {'items': [{'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Tombrello-T-A', 'name': {'family': 'Tombrello', 'given': 'T. A.'}}, {'id': 'Fox-G', 'name': {'family': 'Fox', 'given': 'G.'}}]}
Year: 1974
DOI: 10.1016/0375-9474(74)90715-5
The ^(12)C(α,γ)^(16)O cross section at astrophysical energies has been determined from existing ^(12)C(α, α)^(12)C and ^(12)C(α,γ)^(16)O data by means of a "hybrid" R-matrix - optical model method; we obtain an S-factor of 0.08 _(−0.04)^(+0.05) MeV·b at E_(c.m) = 300 keV. The El γ-ray width of the 9.59 MeV state has been determined to be 23 ± 3 meV.https://authors.library.caltech.edu/records/acjqd-4ez73Microscopic calculation of nuclear dissipation
https://resolver.caltech.edu/CaltechAUTHORS:KOOprc76
Authors: {'items': [{'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Nix-J-R', 'name': {'family': 'Nix', 'given': 'J. R.'}}]}
Year: 1976
DOI: 10.1103/PhysRevC.13.209
By use of a time-dependent wave function of the BCS form, we compute microscopically the energy dissipated for a system with a monopole pairing force moving under the influence of a time-dependent single-particle potential. Quasiparticle generation and coupling of the two-quasiparticle modes of the system are included automatically and provide contact with the Landau-Zener formula. The single-particle potential is related to nuclear shapes generated by viscous hydrodynamical calculations of a fissioning 236U nucleus. We attempt to determine the energy dissipated between the saddle point and scission point by requiring that at the scission point the energy dissipated in the microscopic calculations equal that dissipated in the macroscopic hydrodynamical calculations. This procedure leads to 34 MeV of dissipated energy, which is almost twice the value of 18 MeV obtained from macroscopic hydrodynamical calculations that reproduce experimental fission-fragment kinetic energies. The corresponding value of the nuclear viscosity coefficient determined from the microscopic calculations is 0.04 TP, compared to 0.015 ± 0.005 TP obtained from the macroscopic hydrodynamical calculations. The viscosity coefficient determined from the microscopic calculations is even larger if the dissipated energies are compared at a finite scission neck radius. As a possible resolution of this discrepancy, we propose that level splittings arising from axially asymmetric and reflection-asymmetric deformations during the descent from the saddle point to scission reduce the energy dissipation and make the nuclei only moderately viscous.https://authors.library.caltech.edu/records/kq3h7-r4g38One-dimensional nuclear dynamics in the time-dependent Hartree-Fock approximation
https://resolver.caltech.edu/CaltechAUTHORS:BONprc76
Authors: {'items': [{'id': 'Bonche-P', 'name': {'family': 'Bonche', 'given': 'P.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S.'}}, {'id': 'Negele-J-W', 'name': {'family': 'Negele', 'given': 'J. W.'}}]}
Year: 1976
DOI: 10.1103/PhysRevC.13.1226
The time-dependent Hartree-Fock theory is applied to the large amplitude dynamics of slabs of spin and isospin symmetric nuclear matter. The slabs are translationally invariant in two transverse dimensions, and with the simplified effective interaction used in this work, the problem is reduced to a set of coupled nonlinear equations for time-dependent functions of a single spatial variable. By specification of appropriate initial conditions, large amplitude oscillations of a single slab, the scattering of a slab from an external potential barrier, and collisions of two slabs have been investigated. The results evidence a wide variety of dynamic phenomena, including fusion, compound nucleus formation, dissipation, strongly damped collisions, shock wave propagation, and fragmentation. The microscopic aspects of the dynamics, the relation to fluid mechanics, and the practical and conceptual problems arising from the theory are discussed in detail.https://authors.library.caltech.edu/records/r8ngt-k3a78Time-dependent Hartree-Fock calculations for 16O + 16O and 40Ca + 40Ca reactions
https://resolver.caltech.edu/CaltechAUTHORS:KOOprc77
Authors: {'items': [{'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Davies-K-T-R', 'name': {'family': 'Davies', 'given': 'K. T. R.'}}, {'id': 'Maruhn-Rezwani-V', 'name': {'family': 'Maruhn-Rezwani', 'given': 'V.'}}, {'id': 'Feldmeier-H', 'name': {'family': 'Feldmeier', 'given': 'H.'}}, {'id': 'Krieger-S-J', 'name': {'family': 'Krieger', 'given': 'S. J.'}}, {'id': 'Negele-J-W', 'name': {'family': 'Negele', 'given': 'J. W.'}}]}
Year: 1977
DOI: 10.1103/PhysRevC.15.1359
The time-dependent Hartree-Fock approximation is applied to 16O + 16O and 40Ca + 40Ca reactions. An effective interaction which results in a local Hartree-Fock potential is used. The full time-dependent Hartree-Fock problem is reduced to two dimensions by treating the relative orbital motion of the ions in the rotating frame approximation. The detailed dynamics of the nuclear density matrix during these reactions is discussed. The deflection function, energy loss, fragment charge distribution, and ion-ion potential have been computed for several reactions and compared with available data. The physical content and limitations of our calculations are discussed.https://authors.library.caltech.edu/records/8veg5-s4y21Dynamics of induced fission
https://resolver.caltech.edu/CaltechAUTHORS:NEGprc78
Authors: {'items': [{'id': 'Negele-J-W', 'name': {'family': 'Negele', 'given': 'J. W.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Möller-P', 'name': {'family': 'Möller', 'given': 'P.'}}, {'id': 'Nix-J-R', 'name': {'family': 'Nix', 'given': 'J. R.'}}, {'id': 'Sierk-A-J', 'name': {'family': 'Sierk', 'given': 'A. J.'}}]}
Year: 1978
DOI: 10.1103/PhysRevC.17.1098
Induced fission of 236U is calculated in the time-dependent mean-field approximation assuming axial and reflection symmetry and omitting the spin-orbit interaction. Constrained static solutions are used to generate the appropriate initial condition and are compared in detail with results of macroscopic-microscopic calculations. Although dynamic mean-field results are strongly dependent upon an effective pairing gap, predicted observables are consistent with experiment for plausible values of the gap. Detailed comparisons with macroscopic models indicate that both a modified one-body dissipation and two-body viscosity yield observables similar to those of the mean-field theory, even though these physical dissipation mechanisms are fundamentally different.https://authors.library.caltech.edu/records/98tn0-c7s85Three-dimensional time-dependent Hartree-Fock calculations of 16O + 16O and 40Ca + 40Ca fusion cross sections
https://resolver.caltech.edu/CaltechAUTHORS:BONprc78
Authors: {'items': [{'id': 'Bonche-P', 'name': {'family': 'Bonche', 'given': 'P.'}}, {'id': 'Grammaticos-B', 'name': {'family': 'Grammaticos', 'given': 'B.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S.'}}]}
Year: 1978
DOI: 10.1103/PhysRevC.17.1700
Three-dimensional time-dependent Hartree-Fock calculations for the 16O + 16O and 40Ca + 40Ca fusion excitation functions are presented. Results for the former system are in good agreement with experiment for Elab≤120 MeV and indicate a dynamical lower angular momentum limit to fusion for Elab≥54 MeV. Results for 40Ca + 40Ca are compared with previous two-dimensional calculations. The low-energy fusion cross sections obtained for this system demonstrate the sensitivity of time-dependent Hartree-Fock calculations to the effective interaction used.https://authors.library.caltech.edu/records/3qr2z-52n92Three-dimensional time-dependent Hartree-Fock calculations: Application to 16O + 16O collisions
https://resolver.caltech.edu/CaltechAUTHORS:FLOprc78
Authors: {'items': [{'id': 'Flocard-H', 'name': {'family': 'Flocard', 'given': 'H.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Weiss-M-S', 'name': {'family': 'Weiss', 'given': 'M. S.'}}]}
Year: 1978
DOI: 10.1103/PhysRevC.17.1682
A coordinate-space method is developed to solve the three-dimensional time-dependent Hartree-Fock equations. It is applied to the study of 16O + 16O collisions at Elab=105 MeV for incident angular momenta from O to 40h. We find fusion for L=13h through 27h and highly inelastic scattering for L≤12h.
NUCLEAR REACTIONS 16O(16O,x) in three-dimensional time-dependent Hartree-Fock approximation. Fusion and strongly damped collisions.https://authors.library.caltech.edu/records/1a16t-g2e42Test of the time-dependent mean-field theory in Kr-induced strongly damped collisions
https://resolver.caltech.edu/CaltechAUTHORS:DAVprl78
Authors: {'items': [{'id': 'Davies-K-T-R', 'name': {'family': 'Davies', 'given': 'K. T. R.'}}, {'id': 'Maruhn-Rezwani-V', 'name': {'family': 'Maruhn-Rezwani', 'given': 'V.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Negele-J-W', 'name': {'family': 'Negele', 'given': 'J. W.'}}]}
Year: 1978
DOI: 10.1103/PhysRevLett.41.632
Axially symmetric time-dependent mean-field calculations using a Skyrme-type effective interaction have been performed for 84Kr + 208Pb at Elab=494 MeV and 84Kr + 209Bi at Elab=600 MeV. Calculated fragment energies, mean masses, and scattering angles for strongly damped collisions are in good agreement with experiment, but mass distribution widths are an order of magnitude too small.https://authors.library.caltech.edu/records/v8ezk-ane78Time-dependent Hartree-Fock calculations of fusion cross sections for 16O + 40Ca and 28Si + 28Si
https://resolver.caltech.edu/CaltechAUTHORS:BONprc79
Authors: {'items': [{'id': 'Bonche-P', 'name': {'family': 'Bonche', 'given': 'P.'}}, {'id': 'Davies-K-T-R', 'name': {'family': 'Davies', 'given': 'K. T. R.'}}, {'id': 'Flanders-B', 'name': {'family': 'Flanders', 'given': 'B.'}}, {'id': 'Flocard-H', 'name': {'family': 'Flocard', 'given': 'H.'}}, {'id': 'Grammaticos-B', 'name': {'family': 'Grammaticos', 'given': 'B.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Krieger-S-J', 'name': {'family': 'Krieger', 'given': 'S. J.'}}, {'id': 'Weiss-M-S', 'name': {'family': 'Weiss', 'given': 'M. S.'}}]}
Year: 1979
DOI: 10.1103/PhysRevC.20.641
Time-dependent Hartree-Fock calculations are carried out for the systems 16O + 40Ca and 28Si + 28Si. Cross sections for the formation of 56Ni are qualitatively similar in both cases, although there exist significant quantitative differences which reflect the importance of the entrance channel. Both systems exhibit an angular momentum window for fusion. The results of the calculations are compared with currently available experimental data.https://authors.library.caltech.edu/records/fpk6b-jsv20Coulomb Distortion of Pion Spectra from Heavy-Ion Collisions
https://resolver.caltech.edu/CaltechAUTHORS:LIBprl79
Authors: {'items': [{'id': 'Libbrecht-K-G', 'name': {'family': 'Libbrecht', 'given': 'K. G.'}, 'orcid': '0000-0002-8744-3298'}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1979
DOI: 10.1103/PhysRevLett.43.1581
The effects of final-state π-nucleus electromagnetic interactions in heavy-ion collisions are investigated in a covariant classical formulation. Experimentally observed mid-rapidity peaks in π+ spectra are reproduced by a simple model and are shown to be sensitive to the gross features of the time-dependent nuclear charge distribution.https://authors.library.caltech.edu/records/75bpx-byh43Atomic screening of nuclear transitions
https://resolver.caltech.edu/CaltechAUTHORS:20120718-091056106
Authors: {'items': [{'id': 'Davis-B-R', 'name': {'family': 'Davis', 'given': 'B. R.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Vogel-P', 'name': {'family': 'Vogel', 'given': 'P.'}, 'orcid': '0000-0003-0587-5466'}]}
Year: 1980
DOI: 10.1103/PhysRevC.22.1233
In the analysis of time-reversal and Mössbauer absorption experiments, it is important to consider atomic processes which interfere with the direct nuclear transition. Interaction of the photon with the atomic electrons causes the radiation to acquire a phase shift, specified by the interference parameter ξ(L_π). We present theoretical expressions for ξ and compare our calculated values with experiment. Satisfactory agreement is obtained. In particular, an apparent violation of time-reversal invariance in the 129-keV transition of ^(191)Ir is fully explained by these effects.https://authors.library.caltech.edu/records/nwmr5-g7p79Shape parametrization for liquid-drop studies
https://resolver.caltech.edu/CaltechAUTHORS:TREprc80
Authors: {'items': [{'id': 'Trentalange-S', 'name': {'family': 'Trentalange', 'given': 'S.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Sierk-A-J', 'name': {'family': 'Sierk', 'given': 'A. J.'}}]}
Year: 1980
DOI: 10.1103/PhysRevC.22.1159
We present a new method for defining axially symmetric shapes which is particularly appropriate for describing elongated and multineck configurations. This shape parametrization is used to describe the static properties of incompressible, charged liquid drops. In particular, we calculate the properties of binary-fission saddle points and compare these with results using other methods. We also present the geometrical properties and normal mode analyses of the two-and three-necked saddle-point families.https://authors.library.caltech.edu/records/dxfv9-1vq64Mean-field approximation for inclusive observables
https://resolver.caltech.edu/CaltechAUTHORS:ALHprc81a
Authors: {'items': [{'id': 'Alhassid-Y', 'name': {'family': 'Alhassid', 'given': 'Y.'}}, {'id': 'Müller-B', 'name': {'family': 'Müller', 'given': 'B.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1981
DOI: 10.1103/PhysRevC.23.487
The excitation of a many-body system by a one-body perturbation is considered. The stationary phase approximation to a functional-integral representation of the many-body evolution operator shows that the optimal mean field for describing the final expectation values of one- and two-body operators is that given by the time-dependent Hartree-Fock method. The forced Lipkin model is considered as a test of the mean-field approximation.https://authors.library.caltech.edu/records/2y72q-2fa43Mean-field approximation to the many-body S matrix
https://resolver.caltech.edu/CaltechAUTHORS:ALHprc81b
Authors: {'items': [{'id': 'Alhassid-Y', 'name': {'family': 'Alhassid', 'given': 'Y.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1981
DOI: 10.1103/PhysRevC.23.1590
A nonperturbative method is developed for calculating the excitation of a many-body system by a time-dependent Hamiltonian. The stationary-phase approximation to a functional-integral representation of the interaction-picture many-body evolution operator results in a mean-field approximation to the S matrix which is asymptotically time independent. A one-body temporally nonlocal evolution equation defines the stationary mean-field configurations. The general method and character of the stationary solutions are illustrated by application to the forced harmonic oscillator and forced Lipkin model. Potential applications to realistic nuclear and atomic scattering situations are discussed.https://authors.library.caltech.edu/records/xq8mp-v4f89Skyrme-force time-dependent Hartree-Fock calculations with axial symmetry
https://resolver.caltech.edu/CaltechAUTHORS:20120717-151102912
Authors: {'items': [{'id': 'Davies-K-T-R', 'name': {'family': 'Davies', 'given': 'K. T. R.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1981
We discuss axially symmetric time-dependent Hartree-Fock calculations using a finite-range modification of the Skyrme energy functional. The finite-difference forms of the coordinate-space time-dependent Hartree-Fock equations, the method of time evolution, and other numerical aspects are presented. Detailed results for (^84)Kr-induced deep-inelastic collisions with (^208)Pb at E_(lab) = 494 MeV and with (^209)Bi at E_(lab) = 600 MeV and 714 MeV are compared with experiment.
[NUCLEAR REACTIONS (^84)Kr + (^208)Pb at E_lab = 494 MeV and (^84)Kr + (^209)Bi at E_1ab=600 and 714 MeV, in the time-dependent Hartree-Fock approximation. Strongy
damped collisions. Details of Skyrme force calculations with axial symmetry.]https://authors.library.caltech.edu/records/18zhv-6vf75Direct capture cross sections at low energy
https://resolver.caltech.edu/CaltechAUTHORS:20120719-160049801
Authors: {'items': [{'id': 'Williams-R-D', 'name': {'family': 'Williams', 'given': 'R. D.'}, 'orcid': '0000-0002-9145-8580'}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1981
DOI: 10.1103/PhysRevC.23.2773
We derive simple expressions for the low-energy behavior of direct radiative capture cross sections, particularly
those important in solar nucleosynthesis, such as (^3)He(α,γ)(^7)Be, (^3)H(α,γ)(^7)Li, and (^7)Be(p,y)(^8)B. Our results for the (^3)He(α,γ)(^7)Be reaction are inconsistent with a measurement by Rolfs et al.
[NUCLEAR REACTIONS (^3)He(α,γ)(^7)Be, (^3)H(α,γ)(^7)Li, E<300 keV, (^7)Be(p,y)(^8)B, l Ehttps://authors.library.caltech.edu/records/70app-zjp88Mean-Field Approximation to p + He Scattering
https://resolver.caltech.edu/CaltechAUTHORS:SANprl81
Authors: {'items': [{'id': 'Sandhya-Devi-K-R', 'name': {'family': 'Sandhya Devi', 'given': 'K. R.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1981
DOI: 10.1103/PhysRevLett.47.27
The scattering of protons by helium atoms is studied in a mean-field approximation to the many-body S matrix. The one-body equations governing the electron dynamics for elastic scattering are solved iteratively beginning with the interaction-picture time-dependent Hartree-Fock (TDHF) solution. At a representative proton laboratory energy of 20 keV, the converged S-matrix elements are within 10% of the TDHF value. Inclusive single-charge transfer probabilities calculated in the interaction-picture TDHF approximation agree reasonably well with the experimental data.https://authors.library.caltech.edu/records/r2ad1-kd902Prompt emission of nucleon jets in time-dependent Hartree-Fock collisions
https://resolver.caltech.edu/CaltechAUTHORS:DEVprc81
Authors: {'items': [{'id': 'Sandhya-Devi-K-R', 'name': {'family': 'Devi', 'given': 'K. R. S.'}}, {'id': 'Strayer-M-R', 'name': {'family': 'Strayer', 'given': 'M. R.'}}, {'id': 'Davies-K-T-R', 'name': {'family': 'Davies', 'given': 'K. T. R.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Dhar-A-K', 'name': {'family': 'Dhar', 'given': 'A. K.'}}]}
Year: 1981
DOI: 10.1103/PhysRevC.24.2521
The prompt emission of fact nucleon jets is calculated in the time-dependent Hartree-Fock approximation for 16O+93Nb collisions at Elab=204 MeV. The emission time is independent of the entrance channel angular momentum and is approximately equal to the time needed for projectile nucleons to traverse the target without interacting. The mean laboratory velocity, scattering angle, and particle number of the jet are calculated and interpreted in terms of a zero temperature Fermi gas model. The neutron multiplicity in the jet in coincidence with deep inelastic scattering is found to be consistent with recent experimental measurements.
NUCLEAR REACTIONS 16O+93Nb at ELab=204 MeV in the time dependent Hartree-Fock approximation. Single nucleon emission with fusion and deep inelastic scattering.https://authors.library.caltech.edu/records/r5d0b-k3j72Time-dependent Hartree-Fock theory of charge exchange: Application to He2+ + He
https://resolver.caltech.edu/CaltechAUTHORS:KULpra82
Authors: {'items': [{'id': 'Kulander-K-C', 'name': {'family': 'Kulander', 'given': 'K. C.'}}, {'id': 'Sandhya-Devi-K-R', 'name': {'family': 'Sandhya Devi', 'given': 'K. R.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1982
DOI: 10.1103/PhysRevA.25.2968
An application of the time-dependent Hartree-Fock (TDHF) theory of charge transfer in atomic collisions is presented. Probabilities for elastic and double symmetric charge exchange are calculated for a fixed laboratory scattering angle and for collision energies from 10 to 70 keV. The TDHF equations are solved using finite difference techniques and propagated in time using the Peaceman-Rachford alternating-direction implicit method. Plots of time-evolved charge densities are presented also.https://authors.library.caltech.edu/records/zgn64-16n37Atomic final-state interactions in tritium decay
https://resolver.caltech.edu/CaltechAUTHORS:20120712-094010877
Authors: {'items': [{'id': 'Williams-R-D', 'name': {'family': 'Williams', 'given': 'R. D.'}, 'orcid': '0000-0002-9145-8580'}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1983
DOI: 10.1103/PhysRevC.27.1815
We calculate the effect of the Coulomb interaction of the ejected β ray with the bound atomic electron in the β decay of a tritium atom. The excited state probabilities of the residual helium ion are changed by at most 0.17% from the usual sudden approximation.https://authors.library.caltech.edu/records/cqxer-eck32Coupling of phonons to a helium atom adsorbed on graphite
https://resolver.caltech.edu/CaltechAUTHORS:20120712-094504883
Authors: {'items': [{'id': 'Williams-R-D', 'name': {'family': 'Williams', 'given': 'R. D.'}, 'orcid': '0000-0002-9145-8580'}, {'id': 'Cole-M-W', 'name': {'family': 'Cole', 'given': 'M. W.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1983
We compute the self-energy for a ^4He atom adsorbed on graphite to second order in the phonon coupling. The phonon contributions amount to several degrees Kelvin. The imaginary part corresponds to a lifetime of some 10^(-11) s.https://authors.library.caltech.edu/records/kdnj2-7bc32Comment on "Monte Carlo Evaluation of Functional Integrals Using Coherent-State Slater Determinants"
https://resolver.caltech.edu/CaltechAUTHORS:TROprl83
Authors: {'items': [{'id': 'Troudet-T', 'name': {'family': 'Troudet', 'given': 'T.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1983
DOI: 10.1103/PhysRevLett.51.1103
In a recent letter [1], Avishai and Richert proposed a Monte Carlo evaluation of many-fermion functional integrals using real coherent-state Slater determinants.https://authors.library.caltech.edu/records/mp81z-6mc72Inversion formula for the internucleus potential using sub-barrier fusion cross sections
https://resolver.caltech.edu/CaltechAUTHORS:20120710-093132572
Authors: {'items': [{'id': 'Balantekin-A-B', 'name': {'family': 'Balantekin', 'given': 'A. B.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Negele-J-W', 'name': {'family': 'Negele', 'given': 'J. W.'}}]}
Year: 1983
DOI: 10.1103/PhysRevC.28.1565
Subject to the assumption that sub-barrier fusion is described by an effective one-dimensional energy-independent local potential barrier, the Jeffreys-Wentzel-Kramers-Brillouin approximation for the fusion cross sections is inverted to determine this effective potential. Potential barriers, with their associated experimental errors, are presented for ^(13)C+^(13)C and ^(40)Ca+^(40)Ca, and the assumption of a local effective potential is shown to be inadequate for ^(64)Ni+^(64)Ni.https://authors.library.caltech.edu/records/pvedx-ss295Time-dependent mean-field approximations for many-body observables
https://resolver.caltech.edu/CaltechAUTHORS:TROprc83a
Authors: {'items': [{'id': 'Troudet-T', 'name': {'family': 'Troudet', 'given': 'T.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1983
DOI: 10.1103/PhysRevC.28.1465
The excitation of a many-body system by a time-dependent perturbation is considered within the framework of functional integration. The stationary phase approximation to a functional-integral representation of the final expectation values of many-body observables in the interaction picture leads to a new time-dependent mean-field theory. The resulting equations of motion depend upon the observable itself and consequently are nonlocal in time. The method is illustrated by an analytically soluble application to the forced harmonic oscillator.https://authors.library.caltech.edu/records/c2xjp-ryn32Stochastic solution of a model meson-nucleon field theory
https://resolver.caltech.edu/CaltechAUTHORS:SERprc83
Authors: {'items': [{'id': 'Serot-B-D', 'name': {'family': 'Serot', 'given': 'Brian D.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Negele-J-W', 'name': {'family': 'Negele', 'given': 'J. W.'}}]}
Year: 1983
DOI: 10.1103/PhysRevC.28.1679
Ground-state properties in a model quantum field theory are calculated by stochastic evaluation of a path integral representation of the many-body propagator. The model consists of nonrelativistic nucleons coupled to vector and scalar mesons in one spatial dimension. Binding energies and density distributions are calculated for bound states of up to twenty nucleons. The binding energy as a function of density, the nucleon-nucleon correlation function, and the meson-meson correlation function are evaluated in nuclear matter. Exact ground-state solutions to the full field theory are shown to differ relatively little from those of the potential theory corresponding to the static limit. The exact solutions differ substantially from those of the mean-field (Hartree) approximation, but are quite similar to those obtained in the Hartree-Fock approximation.https://authors.library.caltech.edu/records/vcbks-tv473Unified band-crossing interpretation of 16O+16O inelastic reactions
https://resolver.caltech.edu/CaltechAUTHORS:LANprc83
Authors: {'items': [{'id': 'Langanke-K', 'name': {'family': 'Langanke', 'given': 'K.'}}, {'id': 'Friedrich-H', 'name': {'family': 'Friedrich', 'given': 'H.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1983
DOI: 10.1103/PhysRevLett.51.1231
A band-crossing model based on a microscopically derived 16O+ 16O potential and the Pauli principle is used to interpret data on 16O+ 16O reactions to eight inelastic channels. Structures observed in the cross sections are accounted for in all cases.https://authors.library.caltech.edu/records/egrr3-dza43Continuous representation of many-fermion systems over real Slater determinants
https://resolver.caltech.edu/CaltechAUTHORS:TROprc83b
Authors: {'items': [{'id': 'Troudet-T', 'name': {'family': 'Troudet', 'given': 'T.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1983
DOI: 10.1103/PhysRevC.28.2171
We derive a resolution of unity over real Slater determinants using simple symmetry arguments. The resulting simplification of the measure with respect to the previous representations makes it a good candidate for stochastic evaluations.https://authors.library.caltech.edu/records/e6qwz-r1879Determination of the proximity potential from sub-barrier fusion data
https://resolver.caltech.edu/CaltechAUTHORS:INUprc84
Authors: {'items': [{'id': 'Inui-M', 'name': {'family': 'Inui', 'given': 'M.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1984
DOI: 10.1103/PhysRevC.30.175
Sub-barrier fusion cross sections for 12 systems involving p-shell nuclei are analyzed in an attempt to determine directly the universal form of the internucleus potential. We use a previously developed inversion procedure based on the Wentzel-Kramers-Brillouin approximation, which new model calculations presented here show to be highly accurate. The scaling implied by the proximity formulation is found to be roughly consistent with the data, with the structure of the colliding nuclei having little effect. The proximity function Φ determined from the data is consistent with the original function of Blocki et al. at intermediate separations, subject to the use of a different formula for the nuclear radii. Data for selected systems involving sd-shell nuclei lead to a more attractive potential than that found for the p-shell systems, while data for systems involving Ca isotopes exhibit "reentrant" barriers characteristic of a breakdown of the basic assumptions of the inversion procedure.https://authors.library.caltech.edu/records/v2dpz-yc694Mean-Field Calculations of Fluctuations in Nuclear Collisions
https://resolver.caltech.edu/CaltechAUTHORS:MARprl85
Authors: {'items': [{'id': 'Marston-J-B', 'name': {'family': 'Marston', 'given': 'J. B.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1985
DOI: 10.1103/PhysRevLett.54.1139
We apply the new variational principle of Balian and Veneroni to calculate the fluctuations in final-fragment mass, charge, and kinetic energy for the systems 16O + 16O (Elab-160 MeV) and 40Ca + 40Ca (Elab=278 MeV). The calculated fluctuations are larger than conventional time-dependent Hartree-Fock results and, in the latter case, are consistent with the experimental fragment mass distribution.https://authors.library.caltech.edu/records/ab8rk-ymg40Exact ground-state properties of the SU(2) Hamiltonian lattice gauge theory
https://resolver.caltech.edu/CaltechAUTHORS:CHIprd85
Authors: {'items': [{'id': 'Chin-S-A', 'name': {'family': 'Chin', 'given': 'S. A.'}}, {'id': 'van-Roosmalen-O-S', 'name': {'family': 'van Roosmalen', 'given': 'O. S.'}}, {'id': 'Umland-E-A', 'name': {'family': 'Umland', 'given': 'E. A.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1985
DOI: 10.1103/PhysRevD.31.3201
The SU(2) Hamiltonian lattice gauge theory is shown explicitly to be equivalent to a nonrelativistic quantum many-body problem in S3. By exploiting this equivalence, a many-body Monte Carlo algorithm is devised to solve for its ground-state properties. To the extent that a trial wave function consisting of a product of single-plaquette functions is a good approximation to the exact ground state, the present Monte Carlo method is shown to be an efficient means of calculating the ground-state energy with high precision.https://authors.library.caltech.edu/records/64788-r9w50Hartree-Fock calculations of atoms and molecular chains in strong magnetic fields
https://resolver.caltech.edu/CaltechAUTHORS:NEUpra86
Authors: {'items': [{'id': 'Neuhauser-D', 'name': {'family': 'Neuhauser', 'given': 'D.'}}, {'id': 'Langanke-K', 'name': {'family': 'Langanke', 'given': 'K.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1986
DOI: 10.1103/PhysRevA.33.2084
We calculate the binding energies of atoms and molecular chains in 10^12 G magnetic fields using the Hartree-Fock method. For Z>2 (4) at 1×10^12 (5×10^12), the isolated atom is energetically favored over the molecular chain.https://authors.library.caltech.edu/records/tm4cr-w7e68U(1) lattice gauge theory in the electric-field representation
https://resolver.caltech.edu/CaltechAUTHORS:KOOprd86
Authors: {'items': [{'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Umland-E-A', 'name': {'family': 'Umland', 'given': 'E. A.'}}, {'id': 'Zirnbauer-M-R', 'name': {'family': 'Zirnbauer', 'given': 'M. R.'}}]}
Year: 1986
DOI: 10.1103/PhysRevD.33.1795
The Hamiltonian formulation of U(1) lattice gauge theory is studied in a basis of eigenstates of the electric-field operator. The guided-random-walk algorithm of Chin et al. is transcribed to the electric-field basis, and exact ground-state properties of the theory in three space dimensions are calculated. A novel variational scheme is used to compute the potential between two static charges for two space dimensions.https://authors.library.caltech.edu/records/40qg2-7y248Influence of density fluctuations on solar neutrino conversion
https://resolver.caltech.edu/CaltechAUTHORS:20170818-101641976
Authors: {'items': [{'id': 'Schäfer-A', 'name': {'family': 'Schäfer', 'given': 'Andreas'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'Steven E.'}}]}
Year: 1987
DOI: 10.1016/0370-2693(87)91027-6
The conversion of electron-neutrinos into muon-neutrinos within a star was recently proposed as a mechanism to explain the solar neutrino puzzle. We investigate the influence of density fluctuations on the conversion rate. Although the corrections can become large for suitable choices of parameters they are probably negligible for the sun.https://authors.library.caltech.edu/records/xehtn-1pa73Subbarrier interactions of the oxygen isotopes
https://resolver.caltech.edu/CaltechAUTHORS:PONprc87
Authors: {'items': [{'id': 'Pönisch-V', 'name': {'family': 'Pönisch', 'given': 'V.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1987
DOI: 10.1103/PhysRevC.36.633
We derive a unified description of the low-energy elastic, inelastic, neutron transfer, and fusion cross sections of systems involving two stable oxygen isotopes. Coupled channels equations with an incoming wave boundary condition are employed, as is the no-recoil approximation; the adiabatic approximation, which violates unitarity, is avoided. A calculation with phenomenologically determined 16O + 16O and 16O-n potentials reproduces the measured cross sections within the limitations of the model. A possible error in the data analysis for 16O + 17O by Thomas et al. is pointed out.https://authors.library.caltech.edu/records/a24s4-mp682Proposed experiment to produce and detect light pseudoscalars
https://resolver.caltech.edu/CaltechAUTHORS:BIBprl87
Authors: {'items': [{'id': 'Van-Bibber-K', 'name': {'family': 'Van Bibber', 'given': 'K.'}}, {'id': 'Dagdeviren-N-R', 'name': {'family': 'Dagdeviren', 'given': 'N. R.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Kerman-A-K', 'name': {'family': 'Kerman', 'given': 'A. K.'}}, {'id': 'Nelson-H-N', 'name': {'family': 'Nelson', 'given': 'H. N.'}}]}
Year: 1987
DOI: 10.1103/PhysRevLett.59.759
We propose a laboratory experiment to produce and detect a light neutral pseudoscalar particle that couples to two photons. The pseudoscalar would be produced by a (real) photon from a laser beam interacting with a second (virtual) photon from a static magnetic field; it would be detected after it reconverts to a real photon in a duplicate magnetic field. The bounds on the coupling constant that could be obtained from a null result in such an experiment compete favorably with astrophysical limits and would substantially improve those from direct measurements.https://authors.library.caltech.edu/records/3v6gj-0jm45Importance of the deuteron quadrupole moment in 2H(d,γ)4He
https://resolver.caltech.edu/CaltechAUTHORS:PIEprc87
Authors: {'items': [{'id': 'Piekarewicz-J', 'name': {'family': 'Piekarewicz', 'given': 'J.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1987
DOI: 10.1103/PhysRevC.36.875
We present a phenomenological study of the 2H(d,γ) 4He reaction that allows for the D-state component of the colliding deuterons. The low-energy cross section is determined by an interference between E2 transitions from an initial 5S2 scattering state to either the D- or S-state components of 4He, the latter via the internal quadrupole moment of the deuteron. From a fit to the data, we determine the asymptotic D/S ratio of 4He to be ρ∼-0.40.https://authors.library.caltech.edu/records/tzqbe-qty31Structure of matter in strong magnetic fields
https://resolver.caltech.edu/CaltechAUTHORS:NEUpra87
Authors: {'items': [{'id': 'Neuhauser-D', 'name': {'family': 'Neuhauser', 'given': 'D.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Langanke-K', 'name': {'family': 'Langanke', 'given': 'K.'}}]}
Year: 1987
DOI: 10.1103/PhysRevA.36.4163
We give a detailed presentation of Hartree-Fock calculations of atoms and molecular chains in 10^12 G magnetic fields, as are supposed to exist on the surface of neutron stars. These calculations are the first self-consistent ones treating exchange properly for atoms heavier than helium in high fields. We find that the isolated atom is energetically favored over molecular chains for Z>2 at fields greater than 1×10^12G and for Z>4 at fields greater than 5×10^12 G. These results indicate that matter on the surface of neutron stars is bound very weakly, if at all.https://authors.library.caltech.edu/records/3z9yv-ez131Dynamics of Skyrmion Collisions in 3 + 1 Dimensions
https://resolver.caltech.edu/CaltechAUTHORS:ALLprl87
Authors: {'items': [{'id': 'Allder-A-E', 'name': {'family': 'Allder', 'given': 'A. E.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Seki-R', 'name': {'family': 'Seki', 'given': 'R.'}}, {'id': 'Sommermann-H-M', 'name': {'family': 'Sommermann', 'given': 'H. M.'}}]}
Year: 1987
DOI: 10.1103/PhysRevLett.59.2836
We calculate classical skyrmion collisions in 3+1 dimensions. Numerical integration of Hamilton's equations for the chiral fields is based on a staggered leap-frog method. We study collisions of defensive hedgehog solitons at various impact parameters for center-of-mass energies of 157, 432, and 885 MeV. Internal excitations of the skyrmions and meson emission are observed. The time evolution of the pion field and momentum and baryon densities is shown, as are deflection functions and inelasticities. Some results for skyrmion-antiskyrmion annihilation are presented.https://authors.library.caltech.edu/records/hvw4a-68d44Atomic response to strong laser pulses
https://resolver.caltech.edu/CaltechAUTHORS:WASpra88
Authors: {'items': [{'id': 'Wasson-D-A', 'name': {'family': 'Wasson', 'given': 'D. A.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1988
DOI: 10.1103/PhysRevA.37.1541
We formulate a semiclassical model for the collective response of an atom to a strong laser pulse and use it to study the behavior of the valence shell of xenon. We find that, in a monochromatic wave, a fraction of the shell ionizes rapidly and the rest is driven coherently. The energy distributions of the emitted electrons show reasonable agreement with experimental distributions that are generated via single-particle ionization, indicating that the spectra are independent of the ionization dynamics. The remaining part of the shell is driven coherently and expands with time, thus exerting minimal effect on the core. We also analyze the effects of pulse shape, pulse duration, and the ponderomotive potential. In particular, we present results for femtosecond pulses.https://authors.library.caltech.edu/records/a3ekp-zm715Quantum chaos in a schematic shell model
https://resolver.caltech.edu/CaltechAUTHORS:MERpra88
Authors: {'items': [{'id': 'Meredith-D-C', 'name': {'family': 'Meredith', 'given': 'D. C.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Zirnbauer-M-R', 'name': {'family': 'Zirnbauer', 'given': 'M. R.'}}]}
Year: 1988
DOI: 10.1103/PhysRevA.37.3499
To test the connection between chaotic classical motion and quantum spectral and overlap statistics, we examine a schematic three-orbital shell model. This system is novel in that the quantum phase space is compact and the momentum dependence of the classical Hamiltonian is nonstandard. We find good agreement with the expected behavior of the spectral statistics and reasonable agreement for the overlap distributions. Also, there is evidence that the eigenvector statistics are more sensitive to the details of the classical dynamics than are the eigenvalues.https://authors.library.caltech.edu/records/5mf5a-k9h68Positron interactions with high-Z atoms at relativistic energies
https://resolver.caltech.edu/CaltechAUTHORS:BUTpra88
Authors: {'items': [{'id': 'Butler-M-N', 'name': {'family': 'Butler', 'given': 'M. N.'}}, {'id': 'Chu-M-C', 'name': {'family': 'Chu', 'given': 'M.-C.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Piekarewicz-J', 'name': {'family': 'Piekarewicz', 'given': 'J.'}}]}
Year: 1988
DOI: 10.1103/PhysRevA.38.2274
We consider the interaction of a positron with a bound electron of a high-Z atom. In particular, we present relativistic calculations of the cross sections for knockout and/or positronium formation in a thorium target, as well as an internal process in a hypothetical Z=164 "atom." Both plane-wave and distorted-wave Born approximations are discussed. We find peaks in the final sum energy of the electron-positron pairs due to the momentum distribution of the atomic electron. However, these peaks are too low in energy and are too broad compared with peaks claimed in e+e- scattering or with the anomalous positron peaks in heavy-ion experiments.https://authors.library.caltech.edu/records/y54jj-9x030Simulation of vacancies in a two-dimensional Ising antiferromagnet
https://resolver.caltech.edu/CaltechAUTHORS:BAUprb88
Authors: {'items': [{'id': 'Bauer-W', 'name': {'family': 'Bauer', 'given': 'W.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1988
DOI: 10.1103/PhysRevB.38.8958
We present simulations of one- and two-vacancy states in a two-dimensional square-lattice Ising antiferromagnet. We find that the energy of the single-vacancy ground state scales as J2/3, where J is the spin-spin coupling. The S- and P-wave states of two vacancies are bound, with binding energy scrE∝J2/3 and J, respectively, while the D-wave state is unbound.https://authors.library.caltech.edu/records/gmtk1-nv862Interferometry of the compound nucleus
https://resolver.caltech.edu/CaltechAUTHORS:KOOprl89
Authors: {'items': [{'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Bauer-W', 'name': {'family': 'Bauer', 'given': 'W.'}}, {'id': 'Schäfer-A', 'name': {'family': 'Schäfer', 'given': 'A.'}}]}
Year: 1989
DOI: 10.1103/PhysRevLett.62.1247
We consider interference effects in the inclusive emission of two identical particles from a compound nucleus. Statistical assumptions result in a correlation of the emitted particles that depends upon the coherence properties of the level widths in a form similar to that describing fluctuations in an exclusive cross section. A schematic application to the decay of a rapidly rotating compound nucleus shows that the observed source size can depend upon the kinematics of the measurement.https://authors.library.caltech.edu/records/ydjh3-rsr98Molecular-dynamics simulations of atomic ionization by strong laser fields
https://resolver.caltech.edu/CaltechAUTHORS:WASpra89
Authors: {'items': [{'id': 'Wasson-D-A', 'name': {'family': 'Wasson', 'given': 'D. A.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1989
DOI: 10.1103/PhysRevA.39.5676
We use molecular-dynamics simulations to study the competition between sequential and collective ionization in low-Z atoms by strong laser fields. The model shows sequential ionization at low fields, changing to collective ionization at large fields. The field strength at which this occurs is lower for higher frequencies. We also study the ionization as a function of pulse length and find that collective ionization is favored for shorter pulses.https://authors.library.caltech.edu/records/4r892-dwr63Quasielastic response with a real-time path-integral Monte Carlo method
https://resolver.caltech.edu/CaltechAUTHORS:CARprb90
Authors: {'items': [{'id': 'Carraro-C', 'name': {'family': 'Carraro', 'given': 'C.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1990
DOI: 10.1103/PhysRevB.41.6741
We formulate the quasielastic response of a nonrelativistic many-body system at zero temperature in terms of ground-state density-matrix elements and real-time path integrals that embody the final-state interactions. While the former provide the weight for a conventional Monte Carlo calculation, the latter require a more sophisticated treatment. We argue that the stationary-phase Monte Carlo technique recently developed by Doll et al. can be used to study the approach to "Y scaling." We perform calculations for a particle in a potential well in one and three dimensions and compare them with the exact results available for these models.https://authors.library.caltech.edu/records/c2p1e-25x81Constraints on the 12C(α,γ)16O astrophysical S factor from the beta-delayed α emission of 16N
https://resolver.caltech.edu/CaltechAUTHORS:JIXprc90a
Authors: {'items': [{'id': 'Ji-X', 'name': {'family': 'Ji', 'given': 'Xiangdong'}}, {'id': 'Filippone-B-W', 'name': {'family': 'Filippone', 'given': 'B. W.'}, 'orcid': '0000-0002-2618-2688'}, {'id': 'Humblet-J', 'name': {'family': 'Humblet', 'given': 'J.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1990
DOI: 10.1103/PhysRevC.41.1736
The E1 astrophysical S factor for the 12C(α,γ)16O reaction is studied using R-matrix theory. The constraints on this quantity from the α-particle spectrum following 16N β decay are investigated with a set of pseudodata in an attempt to identify what additional information might be extracted from future measurements. The possibility of an experimental separation of the p- and f-wave α particles is discussed. Additional precise measurements of the β-delayed α particles at total center-of-mass energies near 1.0 MeV and the (α,γ) cross section at energies below and above previous measurements are particularly useful in constraining the S factor.https://authors.library.caltech.edu/records/xbgrr-bey38Estimates of cluster-impact fusion yields
https://resolver.caltech.edu/CaltechAUTHORS:CARpra90
Authors: {'items': [{'id': 'Carraro-C', 'name': {'family': 'Carraro', 'given': 'C.'}}, {'id': 'Chen-B-Q', 'name': {'family': 'Chen', 'given': 'B. Q.'}}, {'id': 'Schramm-S', 'name': {'family': 'Schramm', 'given': 'S.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1990
DOI: 10.1103/PhysRevA.42.1379
We present several theoretical estimates of D+D fusion rates for heavy-water molecular clusters impacting on TiD targets. Our considerations range from the simple thick-target yield to single- and multiple-deuteron knock-on to thermonuclear and thermal-spike models; detailed molecular-dynamics simulations are also presented. Each of our models fails, by many orders of magnitude, to reproduce the yields observed in recent experiments. We consider the extent to which experimental artifacts might contribute to the results claimed.https://authors.library.caltech.edu/records/j00c8-pp470Branching ratios in low-energy deuteron-induced reactions
https://resolver.caltech.edu/CaltechAUTHORS:KOOprc90
Authors: {'items': [{'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Mukerjee-M', 'name': {'family': 'Mukerjee', 'given': 'M.'}}]}
Year: 1990
DOI: 10.1103/PhysRevC.42.1639
We consider (d,p) and (d,n) reactions on light nuclei at low energies. A simple estimate using the second-order distorted-wave Born approximation shows that Coulomb-induced predissociation of the deuteron influences the relative rate by less than 10%. This disagrees with a previous explanation of experiments involving 6Li targets and invalidates speculations about such effects in "cold fusion" experiments.https://authors.library.caltech.edu/records/ptcb7-3ja41Final-state effects on the deep-inelastic response of liquid 4He
https://resolver.caltech.edu/CaltechAUTHORS:CARprl90
Authors: {'items': [{'id': 'Carraro-C', 'name': {'family': 'Carraro', 'given': 'C.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1990
DOI: 10.1103/PhysRevLett.65.2792
We calculate the deep-inelastic response of liquid 4He. Using a universality hypothesis for the bridge function, we obtain a new, highly consistent ground-state Jastrow wave function with condensate fraction n0≃0.081. The dynamics of final-state interactions is accounted for by a Monte Carlo sampling of the scattering wave function of the recoiling He atom. The results, in excellent agreement with recent neutron-scattering measurements, indicate that the response has a more complicated dependence on the structure of the ground state than is assumed by all previous theories.https://authors.library.caltech.edu/records/g9ava-zt770Level matrix, 16N β decay, and the 12C(α,γ)16O reaction
https://resolver.caltech.edu/CaltechAUTHORS:HUMprc91
Authors: {'items': [{'id': 'Humblet-J', 'name': {'family': 'Humblet', 'given': 'J.'}}, {'id': 'Filippone-B-W', 'name': {'family': 'Filippone', 'given': 'B. W.'}, 'orcid': '0000-0002-2618-2688'}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1991
DOI: 10.1103/PhysRevC.44.2530
The level matrix corresponding to the scrK-matrix parametrization of a resonant nuclear reaction is derived and applied to the spectrum of α particles emitted following 16N β decay. The parametrized spectrum is fitted to data simultaneously with the E1 capture cross section of the 12C(α,γ)16O reaction and the p-wave phase shift of 12C(α,α)12C. Our analysis shows that new measurements of the α spectrum from 16N β decay could be used to significantly reduce the uncertainty of the 12C(α,γ)16O astrophysical S factor at 0.3 MeV. Various constraints on the parameters are analyzed and suggestions are made for further reducing the uncertainty in this crucial reaction rate.https://authors.library.caltech.edu/records/5jta5-tmz68Environmental fine structure in low-energy β-particle spectra
https://resolver.caltech.edu/CaltechAUTHORS:20150408-112713508
Authors: {'items': [{'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'Steven E.'}}]}
Year: 1991
DOI: 10.1038/354468a0
Some recent measurements of beta-decay spectra show anomalous line shapes which have been interpreted as providing evidence for a neutrino with a mass of about 17 keV; other similar studies, however, find no anomalies. Regardless of the reason for these discrepancies, such studies require a detailed understanding (at the level of accuracy of one part per thousand) of the spectral shape and the detector response expected in the absence of any exotic phenomena. Influences on the beta decay process from outside the nucleus are of great importance in this regard, and the role of atomic screening corrections and atomic and molecular effects on the spectrum near the end point have been considered previously. These produce only smooth, monotonic distortions of the spectrum. Here I note the existence of an effect, previously overlooked, that results in an oscillatory structure in the beta spectrum. The effect is of sufficient magnitude to be relevant to searches for heavy neutrinos that involve tritium beta decay, and it may also provide a basis for studies of molecular or crystal structure, in a manner analogous to extended X-ray absorption fine structure (EXAFS).https://authors.library.caltech.edu/records/2tvpv-gbp47Baryon-antibaryon annihilation in the Skyrme model
https://resolver.caltech.edu/CaltechAUTHORS:SOMprd92
Authors: {'items': [{'id': 'Sommermann-H-M', 'name': {'family': 'Sommermann', 'given': 'H. M.'}}, {'id': 'Seki-R', 'name': {'family': 'Seki', 'given': 'R.'}}, {'id': 'Larson-S', 'name': {'family': 'Larson', 'given': 'S.'}, 'orcid': '0000-0002-0057-8211'}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1992
DOI: 10.1103/PhysRevD.45.4303
The dynamics of Skyrmion-anti-Skyrmion annihilations in 3+1 dimensions is examined by the numerical integration of the classical Hamilton equations of motion. The baryon number is found to disappear extremely rapidly, close to the causal limit, while the energy distribution still remains concentrated in the annihilation region. The emission of pion waves emitted by the annihilation process is investigated.https://authors.library.caltech.edu/records/kdpbd-rp573Determining the 12C(α,γ) 16O cross section from Coulomb dissociation
https://resolver.caltech.edu/CaltechAUTHORS:SHOprc92
Authors: {'items': [{'id': 'Shoppa-T-D', 'name': {'family': 'Shoppa', 'given': 'T. D.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1992
DOI: 10.1103/PhysRevC.46.382
We estimate the E1 and E2 contributions to the Coulomb dissociation reaction 16O+Pb→α+12C+Pb using semiclassical Coulomb excitation theory. For projectile energies below 300 MeV/nucleon and scattering angles greater than 1°, we find that the process is dominated by the E2 component. This is in contrast to the astrophysically interesting 12C(α,γ)16O cross section, which is dominated by the E1 multipole at the most effective energy of 300 keV. The E2 sensitivity of Coulomb dissociation would usefully complement forthcoming 16N β-decay data, which will constrain only the E1 component.https://authors.library.caltech.edu/records/xr1es-w1874Optical model description of parity-nonconserving neutron resonances
https://resolver.caltech.edu/CaltechAUTHORS:KOOprl92
Authors: {'items': [{'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Johnson-C-W', 'name': {'family': 'Johnson', 'given': 'C. W.'}}, {'id': 'Vogel-P', 'name': {'family': 'Vogel', 'given': 'P.'}, 'orcid': '0000-0003-0587-5466'}]}
Year: 1992
DOI: 10.1103/PhysRevLett.69.1163
We calculate the average helicity dependence of the low-energy neutron-nucleus cross section in terms of a phenomenological optical model. Comparison with recent measurements on 232Th and 238U by the TRIPLE Collaboration shows that the effective parity-nonconserving interaction is two orders of magnitude larger than estimates based on standard meson-exchange models. The helicity dependence is predicted to oscillate with target mass due to shape resonances.https://authors.library.caltech.edu/records/x77rk-zxt98Monte Carlo methods for the nuclear shell model
https://resolver.caltech.edu/CaltechAUTHORS:JOHprl92
Authors: {'items': [{'id': 'Johnson-C-W', 'name': {'family': 'Johnson', 'given': 'C. W.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Lang-G-H', 'name': {'family': 'Lang', 'given': 'G. H.'}}, {'id': 'Ormand-W-E', 'name': {'family': 'Ormand', 'given': 'W. E.'}}]}
Year: 1992
DOI: 10.1103/PhysRevLett.69.3157
We present novel Monte Carlo methods for treating the interacting shell model that allow exact calculations much larger than those heretofore possible. The two-body interaction is linearized by an auxiliary field; Monte Carlo evaluation of the resulting functional integral gives ground-state or thermal expectation values of few-body operators. The "sign problem" generic to quantum Monte Carlo calculations is absent in a number of cases. We discuss the favorable scaling of these methods with nucleon number and basis size and their suitability to parallel computation.https://authors.library.caltech.edu/records/59qv2-4pe16Comment on "Shadow model for sub-barrier fusion applied to light systems"
https://resolver.caltech.edu/CaltechAUTHORS:BARprc93
Authors: {'items': [{'id': 'Barnes-C-A', 'name': {'family': 'Barnes', 'given': 'C. A.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Langanke-K', 'name': {'family': 'Langanke', 'given': 'K.'}}]}
Year: 1993
DOI: 10.1103/PhysRevC.48.479
We demonstrate that the cross sections derived from the "shadow model" for reactions between light nuclei disagree with low-energy laboratory data and exhibit unphysical behavior at energies below those for which data exist. As a consequence, the large thermonuclear reaction rates obtained by Scalia and Figuera [Phys. Rev. C 46, 2610 (1992)] are incorrect.https://authors.library.caltech.edu/records/1ftyv-qz487One- and two-electron atomic screening in fusion reactions
https://resolver.caltech.edu/CaltechAUTHORS:SHOprc93
Authors: {'items': [{'id': 'Shoppa-T-D', 'name': {'family': 'Shoppa', 'given': 'T. D.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Langanke-K', 'name': {'family': 'Langanke', 'given': 'K.'}}, {'id': 'Seki-R', 'name': {'family': 'Seki', 'given': 'R.'}}]}
Year: 1993
DOI: 10.1103/PhysRevC.48.837
Recent laboratory experiments have measured fusion cross sections at center-of-mass energies low enough that the effects of atomic electrons are important. To extract the cross section for bare nuclei from these data (as required for astrophysical applications), it is necessary to understand these screening effects. We present a model in which the evolution of the electron wave function is treated dynamically in the time-dependent Hartree-Fock scheme, while the motion of the nuclei is treated classically. We have calculated screening in the d+2H and d+3He reactions and give the effective screening energy Ue at small internuclear separations as a function of E. The resulting Ue values do not exceed the previously established adiabatic limits, and thus cannot explain the higher screening energies derived from experiment.https://authors.library.caltech.edu/records/w6jtm-7bn59α spectrum from 16N β decay and the 12C(α,γ)16O reaction
https://resolver.caltech.edu/CaltechAUTHORS:HUMprc93
Authors: {'items': [{'id': 'Humblet-J', 'name': {'family': 'Humblet', 'given': 'J.'}}, {'id': 'Filippone-B-W', 'name': {'family': 'Filippone', 'given': 'B. W.'}, 'orcid': '0000-0002-2618-2688'}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1993
DOI: 10.1103/PhysRevC.48.2114
New data on the spectrum of α particles following the 16N β decay are used to revise and extend a previous evaluation of the E1 part of the astrophysical S factor for the 12C(α,γ)16O reaction.https://authors.library.caltech.edu/records/606s7-5xx71Monte Carlo evaluation of path integrals for the nuclear shell model
https://resolver.caltech.edu/CaltechAUTHORS:LANprc93
Authors: {'items': [{'id': 'Lang-G-H', 'name': {'family': 'Lang', 'given': 'G. H.'}}, {'id': 'Johnson-C-W', 'name': {'family': 'Johnson', 'given': 'C. W.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Ormand-W-E', 'name': {'family': 'Ormand', 'given': 'W. E.'}}]}
Year: 1993
DOI: 10.1103/PhysRevC.48.1518
We present in detail a formulation of the shell model as a path integral and Monte Carlo techniques for its evaluation. The formulation, which linearizes the two-body interaction by an auxiliary field, is quite general, both in the form of the effective ''one-body'' Hamiltonian and in the choice of ensemble. In particular, we derive formulas for the use of general (beyond monopole) pairing operators, as well as a novel extraction of the canonical (fixed-particle-number) ensemble via an activity expansion. We discuss the advantages and disadvantages of the various formulations and ensembles and give several illustrative examples. We also discuss and illustrate calculation of the imaginary-time response function and the extraction, by maximum entropy methods, of the corresponding strength function. Finally, we discuss the "sign problem" generic to fermion Monte Carlo calculations, and prove that a wide class of interactions are free of this limitation.https://authors.library.caltech.edu/records/a3hx9-qg076Practical solution to the Monte Carlo sign problem: Realistic calculations of 54Fe
https://resolver.caltech.edu/CaltechAUTHORS:ALHprl94
Authors: {'items': [{'id': 'Alhassid-Y', 'name': {'family': 'Alhassid', 'given': 'Y.'}}, {'id': 'Dean-D-J', 'name': {'family': 'Dean', 'given': 'D. J.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Lang-G-H', 'name': {'family': 'Lang', 'given': 'G.'}}, {'id': 'Ormand-W-E', 'name': {'family': 'Ormand', 'given': 'W. E.'}}]}
Year: 1994
DOI: 10.1103/PhysRevLett.72.613
We present a practical solution to the "sign problem" in the auxiliary field Monte Carlo approach to the nuclear shell model. The method is based on extrapolation from a continuous family of problem-free Hamiltonians. To demonstrate the resultant ability to treat large shell-model problems, we present results for the 54Fe in the full fp-shell basis using the Brown-Richter interaction. We find the Gamow-Teller β+ strength to be quenched by 58% relative to the single-particle estimate, in better agreement with experiment than previous estimates based on truncated bases.https://authors.library.caltech.edu/records/4t2sr-f2160Demonstration of the auxiliary-field Monte Carlo approach for sd-shell nuclei
https://resolver.caltech.edu/CaltechAUTHORS:ORMprc94
Authors: {'items': [{'id': 'Ormand-W-E', 'name': {'family': 'Ormand', 'given': 'W. E.'}}, {'id': 'Dean-D-J', 'name': {'family': 'Dean', 'given': 'D. J.'}}, {'id': 'Johnson-C-W', 'name': {'family': 'Johnson', 'given': 'C. W.'}}, {'id': 'Lang-G-H', 'name': {'family': 'Lang', 'given': 'G. H.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1994
DOI: 10.1103/PhysRevC.49.1422
We apply the auxiliary-field Monte Carlo approach to the nuclear shell model in the 1s-0d configuration space. The Hamiltonian was chosen to have isovector pairing and isoscalar multipole-multipole interactions, and the calculations were performed within the fixed-particle, canonical ensemble. The results demonstrate the feasibility of the method for N≠Z even-even and odd-odd N=Z nuclei. In particular, static observables for even-even Ne isotopes and 22Na compare well with results obtained from exact diagonalization of the Hamiltonian. Response functions are presented for 22Ne and compared with exact results, and the viability of cranked calculations for N≠Z even-even nuclei is addressed. We present methods for computing observables in the canonical ensemble using Fourier extraction, and for determining the nucelar shape.https://authors.library.caltech.edu/records/436gf-z5v49Complete 0ħω calculations of Gamow-Teller strengths for nuclei in the iron region
https://resolver.caltech.edu/CaltechAUTHORS:DEAprl94
Authors: {'items': [{'id': 'Dean-D-J', 'name': {'family': 'Dean', 'given': 'D. J.'}}, {'id': 'Radha-P-B', 'name': {'family': 'Radha', 'given': 'P. B.'}}, {'id': 'Langanke-K', 'name': {'family': 'Langanke', 'given': 'K.'}}, {'id': 'Alhassid-Y', 'name': {'family': 'Alhassid', 'given': 'Y.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Ormand-W-E', 'name': {'family': 'Ormand', 'given': 'W. E.'}}]}
Year: 1994
DOI: 10.1103/PhysRevLett.72.4066
Gamow-Teller strengths for selected nuclei in the iron region (A∼56) have been investigated via shell-model Monte Carlo calculations with realistic interactions in the complete fp basis. Results for all cases show significant quenching relative to single-particle estimates, in quantitative agreement with (n,p) data. The T=0 residual interaction and the f7/2-f5/2 spin-orbit splitting are shown to play major roles in the quenching mechanism. Calculated B(E2,21+→01+) values are in fair agreement with experiment using effective charges of ep=1.1e and en=0.1e.https://authors.library.caltech.edu/records/zpq3y-j7648Thermal properties of 54Fe
https://resolver.caltech.edu/CaltechAUTHORS:DEAprl95
Authors: {'items': [{'id': 'Dean-D-J', 'name': {'family': 'Dean', 'given': 'D. J.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Langanke-K', 'name': {'family': 'Langanke', 'given': 'K.'}}, {'id': 'Radha-P-B', 'name': {'family': 'Radha', 'given': 'P. B.'}}, {'id': 'Alhassid-Y', 'name': {'family': 'Alhassid', 'given': 'Y.'}}]}
Year: 1995
DOI: 10.1103/PhysRevLett.74.2909
We study the thermal properties of 54Fe with the Brown-Richter interaction in the complete 1p0f model space. Monte Carlo calculations show a peak in the heat capacity and rapid increases in both the moment of inertia and M1 strength near a temperature of 1.1 MeV that are associated with the vanishing of proton-proton and neutron-neutron monopole pair correlations; neutron-proton correlations persist to higher temperatures. Our results are consistent with a Fermi gas level density whose backshift vanishes with increasing temperature.https://authors.library.caltech.edu/records/fecx0-v7113^7Be(p,γ)^8B cross section and the properties of ^7Be
https://resolver.caltech.edu/CaltechAUTHORS:20120216-094113443
Authors: {'items': [{'id': 'Csόtό-A', 'name': {'family': 'Csόtό', 'given': 'A.'}}, {'id': 'Langanke-K', 'name': {'family': 'Langanke', 'given': 'K.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Shoppa-T-D', 'name': {'family': 'Shoppa', 'given': 'T. D.'}}]}
Year: 1995
DOI: 10.1103/PhysRevC.52.1130
We study the nonresonant part of the ^7Be(p,γ)^8B reaction using a three-cluster resonating group model that is variationally converged and virtually complete in ^4He+^3He+p model space. The importance of using adequate nucleon-nucleon interaction is demonstrated. We find that the low-energy astrophysical S factor is linearly correlated with the quadrupole moment of ^7Be. A range of parameters is found where the most important ^8B, ^7Be, and ^7Li properties are reproduced simultaneously; the corresponding S factor at E_(c.m.)=20 keV is 24.6–26.1 eV b.https://authors.library.caltech.edu/records/fr25f-s1x51Shell-model Monte Carlo studies of fp-shell nuclei
https://resolver.caltech.edu/CaltechAUTHORS:LANprc95
Authors: {'items': [{'id': 'Langanke-K', 'name': {'family': 'Langanke', 'given': 'K.'}}, {'id': 'Dean-D-J', 'name': {'family': 'Dean', 'given': 'D. J.'}}, {'id': 'Radha-P-B', 'name': {'family': 'Radha', 'given': 'P. B.'}}, {'id': 'Alhassid-Y', 'name': {'family': 'Alhassid', 'given': 'Y.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1995
DOI: 10.1103/PhysRevC.52.718
We study the gross properties of even-even and N=Z nuclei with A=48–64 using shell-model Monte Carlo methods. Our calculations account for all 0ħω configurations in the fp shell and employ the modified Kuo-Brown interaction KB3. We find good agreement with data for masses and total B(E2) strengths, the latter employing effective charges ep=1.35e and en=0.35e. The calculated total Gamow-Teller strengths agree consistently with the B(GT+) values deduced from (n,p) data if the shell-model results are renormalized by 0.64, as has already been established for sd-shell nuclei. The present calculations therefore suggest that this renormalization (i.e., gA=1 in the nuclear medium) is universal.https://authors.library.caltech.edu/records/zw5gz-d0763Shell model Monte Carlo method for two-neutrino double beta decay
https://resolver.caltech.edu/CaltechAUTHORS:RADprl96
Authors: {'items': [{'id': 'Radha-P-B', 'name': {'family': 'Radha', 'given': 'P. B.'}}, {'id': 'Dean-D-J', 'name': {'family': 'Dean', 'given': 'D. J.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Kuo-T-T-S', 'name': {'family': 'Kuo', 'given': 'T. T. S.'}}, {'id': 'Langanke-K', 'name': {'family': 'Langanke', 'given': 'K.'}}, {'id': 'Poves-A', 'name': {'family': 'Poves', 'given': 'A.'}}, {'id': 'Retamosa-J', 'name': {'family': 'Retamosa', 'given': 'J.'}}, {'id': 'Vogel-P', 'name': {'family': 'Vogel', 'given': 'P.'}, 'orcid': '0000-0003-0587-5466'}]}
Year: 1996
DOI: 10.1103/PhysRevLett.76.2642
Shell model Monte Carlo techniques are used to calculate two-neutrino double beta decay matrix elements. We test the approach against direct diagonalization for 48Ca in the complete pf shell using the KB3 interaction. The method is then applied to the decay of 76Ge in the (0f5/2,1p,0g9/2) model space using a newly calculated realistic interaction. Our result for the matrix element is 0.12±0.05 MeV-1, in reasonable agreement with the experimental value.https://authors.library.caltech.edu/records/dfzn5-kap60Shell model Monte Carlo studies of γ-soft nuclei
https://resolver.caltech.edu/CaltechAUTHORS:ALHprl96
Authors: {'items': [{'id': 'Alhassid-Y', 'name': {'family': 'Alhassid', 'given': 'Y.'}}, {'id': 'Bertsch-G-F', 'name': {'family': 'Bertsch', 'given': 'G. F.'}}, {'id': 'Dean-D-J', 'name': {'family': 'Dean', 'given': 'D. J.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1996
DOI: 10.1103/PhysRevLett.77.1444
We present shell model Monte Carlo calculations for nuclei in the full major shell 50–82 for both protons and neutrons. For the interaction we use a pairing plus quadrupole derived from a surface-peaked separable force. The methods are illustrated for 124Sn, 128Te, and 124Xe. We calculate shape distributions, moments of inertia, and pairing correlations as functions of temperature and angular velocity. Our calculations are the first microscopic evidence of γ-softness of nuclei in this region.https://authors.library.caltech.edu/records/zzz74-7n610Phase transitions in quantum dots
https://resolver.caltech.edu/CaltechAUTHORS:MULprb96
Authors: {'items': [{'id': 'Müller-H-M', 'name': {'family': 'Müller', 'given': 'H.-M.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1996
DOI: 10.1103/PhysRevB.54.14532
We perform Hartree-Fock calculations to show that quantum dots (i.e., two-dimensional systems of up to twenty interacting electrons in an external parabolic potential) undergo a gradual transition to a spin-polarized Wigner crystal with increasing magnetic-field strength. The phase diagram and ground-state energies have been determined. We tried to improve the ground state of the Wigner crystal by introducing a Jastrow ansatz for the wave function and performing a variational Monte Carlo calculation. The existence of so-called magic numbers was also investigated. Finally, we also calculated the heat capacity associated with the rotational degree of freedom of deformed many-body states.https://authors.library.caltech.edu/records/3d44h-9ga54Results from Shell-Model Monte Carlo studies
https://resolver.caltech.edu/CaltechAUTHORS:KOOarnps97
Authors: {'items': [{'id': 'Koonin-S-E', 'name': {'family': 'Koonin\xad', 'given': 'S. E.'}}, {'id': 'Dean-D-J', 'name': {'family': 'Dean\xad', 'given': 'D. J.'}}, {'id': 'Langanke-K', 'name': {'family': 'Langanke\xad', 'given': 'K.'}}]}
Year: 1997
DOI: 10.1146/annurev.nucl.47.1.463
We review results obtained using Shell-Model Monte Carlo (SMMC) techniques. These methods reduce the imaginary-time many-body evolution operator to a coherent superposition of one-body evolutions in fluctuating one-body fields; the resultant path integral is evaluated stochastically. After a brief review of the methods, we discuss a variety of nuclear-physics applications. These include studies of the ground-state properties of pf-shell nuclei, Gamow-Teller strength distributions, thermal and rotational pairing properties of nuclei near N = Z, γ-soft nuclei, and ββ-decay in ⁷⁶Ge. Several other illustrative calculations are also reviewed. Finally, we discuss prospects for further progress in SMMC and related calculations.https://authors.library.caltech.edu/records/5517q-nf413Spin-polarization response functions in high-energy (e→,e′,p→) reactions
https://resolver.caltech.edu/CaltechAUTHORS:ITOprc97
Authors: {'items': [{'id': 'Ito-H', 'name': {'family': 'Ito', 'given': 'Hiroshi'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Seki-R', 'name': {'family': 'Seki', 'given': 'Ryoichi'}}]}
Year: 1997
DOI: 10.1103/PhysRevC.56.3231
Spin-polarization response functions for the high-energy (e→,e′p→) reaction are examined by computing all 18 response functions for proton kinetic energies of 0.515 and 3.170 GeV from an 16O target. The Dirac eikonal formalism is applied to account for the final-state interactions. It is found to yield the response functions in good agreement with those calculated by partial-wave expansion at 0.5 GeV. We identify the response functions that are dominantly determined by the spin-orbit potential in the final-state interaction. Dependence on the Dirac- or Pauli-type current of the nucleon is investigated in the helicity-dependent response functions, and the normal-component polarization of the knocked-out proton is computed.https://authors.library.caltech.edu/records/b93ka-zt125Gamow-Teller strength distributions in fp-shell nuclei
https://resolver.caltech.edu/CaltechAUTHORS:RADprc97
Authors: {'items': [{'id': 'Radha-P-B', 'name': {'family': 'Radha', 'given': 'P. B.'}}, {'id': 'Dean-D-J', 'name': {'family': 'Dean', 'given': 'D. J.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Langanke-K', 'name': {'family': 'Langanke', 'given': 'K.'}}, {'id': 'Vogel-P', 'name': {'family': 'Vogel', 'given': 'P.'}, 'orcid': '0000-0003-0587-5466'}]}
Year: 1997
DOI: 10.1103/PhysRevC.56.3079
We use the shell model Monte Carlo method to calculate complete 0f1p-shell response functions for Gamow-Teller (GT) operators and obtain the corresponding strength distributions using a maximum entropy technique. The approach is validated against direct diagonalization for 48Ti. Calculated GT strength distributions agree well with data from (n,p) and (p,n) reactions for nuclei with A=48–64. We also calculate the temperature evolution of the GT+ distributions for representative nuclei and find that the GT+ distributions broaden and the centroids shift to lower energies with increasing temperature.https://authors.library.caltech.edu/records/6acnt-ee187Human Genome Project: Data Quality
https://resolver.caltech.edu/CaltechAUTHORS:20141125-102829500
Authors: {'items': [{'id': 'Green-P', 'name': {'family': 'Green', 'given': 'Phil'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'Steven E.'}}]}
Year: 1998
DOI: 10.1126/science.279.5354.1113f
Steven E. Koonin's interdisciplinary perspective on the Human Genome Project (Science's Compass, 2 Jan., p. 36) is intriguing, but I would like to comment on two key issues regarding data quality.https://authors.library.caltech.edu/records/5b1k4-art96A different view
https://resolver.caltech.edu/CaltechAUTHORS:20150617-141214531
Authors: {'items': [{'id': 'Alkire-R-C', 'name': {'family': 'Alkire', 'given': 'Richard C.'}}, {'id': 'Koehn-R-K', 'name': {'family': 'Koehn', 'given': 'Richard K.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'Steven E.'}}, {'id': 'Kruger-C-H', 'name': {'family': 'Kruger', 'given': 'Charles'}}, {'id': 'Zimmer-R-J', 'name': {'family': 'Zimmer', 'given': 'Robert J.'}}]}
Year: 1998
DOI: 10.1038/32268
Colin Macilwain's News article of 22 January and your leading article of 29 January (Nature 391311–312 & 419; 1998) offer one perspective on the US Department of Energy's Academic Strategic Alliances Program (ASAP). As the senior research administrators of the five universities involved, we offer another.https://authors.library.caltech.edu/records/q6448-m7z37Solar fusion cross sections
https://resolver.caltech.edu/CaltechAUTHORS:ADErmp98
Authors: {'items': [{'id': 'Adelberger-E-G', 'name': {'family': 'Adelberger', 'given': 'Eric G.'}}, {'id': 'Austin-S-M', 'name': {'family': 'Austin', 'given': 'Sam M.'}}, {'id': 'Bahcall-J-N', 'name': {'family': 'Bahcall', 'given': 'John N.'}}, {'id': 'Balantekin-A-B', 'name': {'family': 'Balantekin', 'given': 'A. B.'}}, {'id': 'Bogaert-G', 'name': {'family': 'Bogaert', 'given': 'Gilles'}}, {'id': 'Brown-L-S', 'name': {'family': 'Brown', 'given': 'Lowell S.'}}, {'id': 'Buchmann-L', 'name': {'family': 'Buchmann', 'given': 'Lothar'}}, {'id': 'Cecil-F-E', 'name': {'family': 'Cecil', 'given': 'F. Edward'}}, {'id': 'Champagne-A-E', 'name': {'family': 'Champagne', 'given': 'Arthur E.'}}, {'id': 'Braeckeleer-L-D', 'name': {'family': 'Braeckeleer', 'given': 'Ludwig de'}}, {'id': 'Elliott-C-A', 'name': {'family': 'Duba', 'given': 'Charles A.'}}, {'id': 'Elliott\xad-S-R', 'name': {'family': 'Elliott', 'given': 'Steven R.'}}, {'id': 'Freedman-S-J', 'name': {'family': 'Freedman', 'given': 'Stuart J.'}}, {'id': 'Gai-M', 'name': {'family': 'Gai', 'given': 'Moshe'}}, {'id': 'Goldring-G', 'name': {'family': 'Goldring', 'given': 'G.'}}, {'id': 'Gould-C-R', 'name': {'family': 'Gould', 'given': 'Christopher R.'}}, {'id': 'Gruzinov-A', 'name': {'family': 'Gruzinov', 'given': 'Andrei'}}, {'id': 'Haxton-W-C', 'name': {'family': 'Haxton', 'given': 'Wick C.'}}, {'id': 'Heeger-K-M', 'name': {'family': 'Heeger', 'given': 'Karsten M.'}}, {'id': 'Henley-E', 'name': {'family': 'Henley', 'given': 'Ernest'}}, {'id': 'Johnson-C-W', 'name': {'family': 'Johnson', 'given': 'Calvin W.'}}, {'id': 'Kamionkowski-M', 'name': {'family': 'Kamionkowski', 'given': 'Marc'}, 'orcid': '0000-0001-7018-2055'}, {'id': 'Kavanagh-R-W', 'name': {'family': 'Kavanagh', 'given': 'Ralph W.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'Steven E.'}}, {'id': 'Kubodera-K', 'name': {'family': 'Kubodera', 'given': 'Kuniharu'}}, {'id': 'Langanke-K', 'name': {'family': 'Langanke', 'given': 'Karlheinz'}}, {'id': 'Motobayashi-T', 'name': {'family': 'Motobayashi', 'given': 'Tohru'}}, {'id': 'Pandharipande-V', 'name': {'family': 'Pandharipande', 'given': 'Vijay'}}, {'id': 'Parker-P', 'name': {'family': 'Parker', 'given': 'Peter'}}, {'id': 'Robertson-R-G-H', 'name': {'family': 'Robertson', 'given': 'R. G. H.'}}, {'id': 'Rolfs-C', 'name': {'family': 'Rolfs', 'given': 'Claus'}}, {'id': 'Sawyer-R-F', 'name': {'family': 'Sawyer', 'given': 'R. F.'}}, {'id': 'Shaviv-N', 'name': {'family': 'Shaviv', 'given': 'N.'}}, {'id': 'Shoppa-T-D', 'name': {'family': 'Shoppa', 'given': 'T. D.'}}, {'id': 'Snover-K-A', 'name': {'family': 'Snover', 'given': 'K. A.'}}, {'id': 'Swanson-E', 'name': {'family': 'Swanson', 'given': 'Erik'}}, {'id': 'Tribble-R-E', 'name': {'family': 'Tribble', 'given': 'Robert E.'}}, {'id': 'Turck-Chièze-S', 'name': {'family': 'Turck-Chièze', 'given': 'Sylvaine'}}, {'id': 'Wilkerson-J-F', 'name': {'family': 'Wilkerson', 'given': 'John F.'}}]}
Year: 1998
DOI: 10.1103/RevModPhys.70.1265
We review and analyze the available information on the nuclear-fusion cross sections that are most important for solar energy generation and solar neutrino production. We provide best values for the low-energy cross-section factors and, wherever possible, estimates of the uncertainties. We also describe the most important experiments and calculations that are required in order to improve our knowledge of solar fusion rates.https://authors.library.caltech.edu/records/x7hq2-t6996Shell-model Monte Carlo studies of neutron-rich nuclei in the 1s-0d-1p-0f shells
https://resolver.caltech.edu/CaltechAUTHORS:DEAprc99a
Authors: {'items': [{'id': 'Dean-D-J', 'name': {'family': 'Dean', 'given': 'D. J.'}}, {'id': 'Ressell-M-T', 'name': {'family': 'Ressell', 'given': 'M. T.'}}, {'id': 'Hjorth-Jensen-M', 'name': {'family': 'Hjorth-Jensen', 'given': 'M.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Langanke-K', 'name': {'family': 'Langanke', 'given': 'K.'}}, {'id': 'Zuker-A-P', 'name': {'family': 'Zuker', 'given': 'A. P.'}}]}
Year: 1999
DOI: 10.1103/PhysRevC.59.2474
We demonstrate the feasibility of realistic shell-model Monte Carlo (SMMC) calculations spanning multiple major shells, using a realistic interaction whose bad saturation and shell properties have been corrected by a newly developed general prescription. Particular attention is paid to the approximate restoration of translational invariance. The model space consists of the full sd-pf shells. We include in the study some well-known T=0 nuclei and several unstable neutron-rich ones around N=20,28. The results indicate that SMMC calculations can reproduce binding energies, B(E2) transitions, and other observables with an interaction that is practically parameter free. Some interesting insight is gained into the nature of deep correlations. The validity of previous studies is confirmed.https://authors.library.caltech.edu/records/0qy6m-a3363Calculation of exciton densities in the shell-model Monte Carlo method
https://resolver.caltech.edu/CaltechAUTHORS:DEAprc99b
Authors: {'items': [{'id': 'Dean-D-J', 'name': {'family': 'Dean', 'given': 'D. J.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 1999
DOI: 10.1103/PhysRevC.60.054306
We develop a shell-model Monte Carlo method to calculate densities of states with varying exciton (particle-hole) number. We then apply this method to the doubly closed-shell nucleus 40Ca in a full 0s-1d-0f-1p shell-model space and compare our results to those found using approximate analytic expressions for the partial densities. We find that the effective one-body level density is reduced by approximately 22% when a residual two-body interaction is included in the shell-model calculation.https://authors.library.caltech.edu/records/62485-rev76Shell model Monte Carlo investigation of rare earth nuclei
https://resolver.caltech.edu/CaltechAUTHORS:WHIprc00
Authors: {'items': [{'id': 'White-J-A', 'name': {'family': 'White', 'given': 'J. A.'}, 'orcid': '0000-0002-7009-3332'}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Dean-D-J', 'name': {'family': 'Dean', 'given': 'D. J.'}}]}
Year: 2000
DOI: 10.1103/PhysRevC.61.034303
We utilize the shell model Monte Carlo method to study the structure of rare earth nuclei. This work demonstrates the first systematic full oscillator shell with intruder calculations in such heavy nuclei. Exact solutions of a pairing plus quadrupole Hamiltonian are compared with the static path approximation in several dysprosium isotopes from A=152 to 162, including the odd mass A=153. Some comparisons are also made with Hartree-Fock-Bogoliubov results from Baranger and Kumar. Basic properties of these nuclei at various temperatures and spin are explored. These include energy, deformation, moments of inertia, pairing channel strengths, band crossing, and evolution of shell model occupation numbers. Exact level densities are also calculated and, in the case of 162Dy, compared with experimental data.https://authors.library.caltech.edu/records/x3mbn-pb880Nuclear matter on a lattice
https://resolver.caltech.edu/CaltechAUTHORS:MULprc00
Authors: {'items': [{'id': 'Müller-H-M', 'name': {'family': 'Müller', 'given': 'H.-M.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Seki-R', 'name': {'family': 'Seki', 'given': 'R.'}}, {'id': 'van-Kolck-U', 'name': {'family': 'van Kolck', 'given': 'U.'}}]}
Year: 2000
DOI: 10.1103/PhysRevC.61.044320
We investigate nuclear matter on a cubic lattice. An exact thermal formalism is applied to nucleons with a Hamiltonian that accommodates on-site and next-neighbor parts of the central, spin-, and isospin-exchange interactions. We describe the nuclear matter Monte Carlo methods which contain elements from shell model Monte Carlo methods and from numerical simulations of the Hubbard model. We show that energy and basic saturation properties of nuclear matter can be reproduced. Evidence of a first-order phase transition from an uncorrelated Fermi gas to a clustered system is observed by computing mechanical and thermodynamical quantities such as compressibility, heat capacity, entropy, and grand potential. We compare symmetry energy and first sound velocities with literature and find reasonable agreement.https://authors.library.caltech.edu/records/8kspa-km373Effect of the source charge on charged-boson interferometry
https://resolver.caltech.edu/CaltechAUTHORS:SHOprc00
Authors: {'items': [{'id': 'Shoppa-T-D', 'name': {'family': 'Shoppa', 'given': 'T. D.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}, {'id': 'Seki-R', 'name': {'family': 'Seki', 'given': 'R.'}}]}
Year: 2000
DOI: 10.1103/PhysRevC.61.054902
We investigate quantal perturbations of the interferometric correlations of charged bosons by the Coulomb field of an instantaneous, charged source. The source charge increases the apparent source size by weakening the correlation at nonzero relative momenta. The effect is strongest for pairs with a small total momentum and is stronger for kaons than for pions of the same momenta. The low-energy data currently available are well described by this effect. A simple expression is proposed to account for the effect.https://authors.library.caltech.edu/records/e2cbp-z7m35Earthshine observations of the Earth's reflectance
https://resolver.caltech.edu/CaltechAUTHORS:20141027-101109172
Authors: {'items': [{'id': 'Goode-P-R', 'name': {'family': 'Goode', 'given': 'P. R.'}}, {'id': 'Qiu-J', 'name': {'family': 'Qiu', 'given': 'J.'}}, {'id': 'Yurchysyn-V', 'name': {'family': 'Yurchyshyn', 'given': 'V.'}}, {'id': 'Hickey-J', 'name': {'family': 'Hickey', 'given': 'J.'}}, {'id': 'Chu-M-C', 'name': {'family': 'Chu', 'given': 'M.-C.'}}, {'id': 'Kolbe-E', 'name': {'family': 'Kolbe', 'given': 'E.'}}, {'id': 'Brown-C-T', 'name': {'family': 'Brown', 'given': 'C. T.'}, 'orcid': '0000-0001-6001-2677'}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 2001
DOI: 10.1029/2000GL012580
Regular photometric observations of the moon's "ashen light" (earthshine) from the Big Bear Solar Observatory (BBSO) since December 1998 have quantified the earth's optical reflectance. We find large (∼5%) daily variations in the reflectance due to large-scale weather changes on the other side of the globe. Separately, we find comparable hourly variations during the course of many nights as the earth's rotation changes that portion of the earth in view. Our data imply an average terrestrial albedo of 0.297±0.005, which agrees with that from simulations based upon both changing snow and ice cover and satellite-derived cloud cover (0.296±0.002). However, we find seasonal variations roughly twice those of the simulation, with the earth being brightest in the spring. Our results suggest that long-term earthshine observations are a useful monitor of the earth's albedo. Comparison with more limited earthshine observations during 1994–1995 show a marginally higher albedo then.https://authors.library.caltech.edu/records/8qeea-3n708Changes in Earth's Reflectance over the Past Two Decades
https://resolver.caltech.edu/CaltechAUTHORS:20141119-110806555
Authors: {'items': [{'id': 'Pallé-E', 'name': {'family': 'Pallé', 'given': 'E.'}}, {'id': 'Goode-P-R', 'name': {'family': 'Goode', 'given': 'P. R.'}}, {'id': 'Montañés-Rodríguez-P', 'name': {'family': 'Montañés-Rodríguez', 'given': 'P.'}}, {'id': 'Koonin-S-E', 'name': {'family': 'Koonin', 'given': 'S. E.'}}]}
Year: 2004
DOI: 10.1126/science.1094070
We correlate an overlapping period of earthshine measurements of Earth's reflectance (from 1999 through mid-2001) with satellite observations of global cloud properties to construct from the latter a proxy measure of Earth's global shortwave reflectance. This proxy shows a steady decrease in Earth's reflectance from 1984 to 2000, with a strong climatologically significant drop after 1995. From 2001 to 2003, only earthshine data are available, and they indicate a complete reversal of the decline. Understanding how the causes of these decadal changes are apportioned between natural variability, direct forcing, and feedbacks is fundamental to confidently assessing and predicting climate change.https://authors.library.caltech.edu/records/8vgfy-byy09