Steven C. Pieper
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
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Research Interests
Steven C. Pieper has a total of 118 co-authors. Here are the top co-authors by number of shared publications:
- R. B. Wiringa
Argonne National Laboratory
31 shared publications - Rocco Schiavilla
Theory Center, Jefferson Laboratory, Newport News, Virginia 23606, USA
10 shared publications - Joseph Carlson
Los Alamos National Laboratory
9 shared publications - Kalman Varga
Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
4 shared publications - Muslema Pervin
Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
4 shared publications - Saori Pastore
Department of Physics and Astronomy University of South Carolina 29208 Columbia South Carolina
4 shared publications
Latest Publications
- 28 February 2017
- Published by Office of Scientific and Technical Information (OSTI)
Nuclear Physics Exascale Requirements Review: An Office of Science review sponsored jointly by Advanced Scientific Computing Research and Nuclear Physics, June 15 - 17, 2016, Gaithersburg, Maryland
Imagine being able to predict — with unprecedented accuracy and precision — the structure of the proton and neutron, and the forces between them, directly from the dynamics of quarks and gluons, and then using this information in calculations of the structure and reactions of atomic nuclei and of the properties of dense neutron stars (NSs). Also imagine discovering new and exotic states of matter, and new laws of nature, by being able to collect more experimental data than we dream possible today, analyzing it in real time to feed back into an experiment, and curating the data with full tracking capabilities and with fully distributed data mining capabilities. Making this vision a reality would improve basic scientific understanding, enabling us to precisely calculate, for example, the spectrum of gravity waves emitted during NS coalescence, and would have important societal applications in nuclear energy research, stockpile stewardship, and other areas. This review presents the components and characteristics of the exascale computing ecosystems necessary to realize this vision.
- 28 February 2017
- Published by Office of Scientific and Technical Information (OSTI)
Nuclear Physics Exascale Requirements Review: An Office of Science review sponsored jointly by Advanced Scientific Computing Research and Nuclear Physics, June 15 - 17, 2016, Gaithersburg, Maryland
Imagine being able to predict — with unprecedented accuracy and precision — the structure of the proton and neutron, and the forces between them, directly from the dynamics of quarks and gluons, and then using this information in calculations of the structure and reactions of atomic nuclei and of the properties of dense neutron stars (NSs). Also imagine discovering new and exotic states of matter, and new laws of nature, by being able to collect more experimental data than we dream possible today, analyzing it in real time to feed back into an experiment, and curating the data with full tracking capabilities and with fully distributed data mining capabilities. Making this vision a reality would improve basic scientific understanding, enabling us to precisely calculate, for example, the spectrum of gravity waves emitted during NS coalescence, and would have important societal applications in nuclear energy research, stockpile stewardship, and other areas. This review presents the components and characteristics of the exascale computing ecosystems necessary to realize this vision.
- Open Access
- 25 August 2014
- Published by American Physical Society (APS) in Physical Review C
- Vol. 90 (2) , 024321
Quantum Monte Carlo calculations of electromagnetic transitions inwith meson-exchange currents derived from chiral effective field theoryWe report quantum Monte Carlo calculations of electromagnetic transitions in . The realistic Argonne two-nucleon and Illinois-7 three-nucleon potentials are used to generate the ground state and nine excited states, with energies that are in excellent agreement with experiment. A dozen and eight transition matrix elements between these states are then evaluated. The matrix elements are computed only in impulse approximation, with those transitions from broad resonant states requiring special treatment. The matrix elements include two-body meson-exchange currents derived from chiral effective field theory, which typically contribute 20%–30% of the total expectation value. Many of the transitions are between isospin-mixed states; the calculations are performed for isospin-pure states and then combined with empirical mixing coefficients to compare to experiment. Alternate mixings are also explored. In general, we find that transitions between states that have the same dominant spatial symmetry are in reasonable agreement with experiments, but transitions between different spatial symmetries are often underpredicted.- 25 August 2014
- Published by American Physical Society (APS) in Physical Review C
- Vol. 90 (2) , 024321
Open AccessQuantum Monte Carlo calculations of electromagnetic transitions inwith meson-exchange currents derived from chiral effective field theoryWe report quantum Monte Carlo calculations of electromagnetic transitions in . The realistic Argonne two-nucleon and Illinois-7 three-nucleon potentials are used to generate the ground state and nine excited states, with energies that are in excellent agreement with experiment. A dozen and eight transition matrix elements between these states are then evaluated. The matrix elements are computed only in impulse approximation, with those transitions from broad resonant states requiring special treatment. The matrix elements include two-body meson-exchange currents derived from chiral effective field theory, which typically contribute 20%–30% of the total expectation value. Many of the transitions are between isospin-mixed states; the calculations are performed for isospin-pure states and then combined with empirical mixing coefficients to compare to experiment. Alternate mixings are also explored. In general, we find that transitions between states that have the same dominant spatial symmetry are in reasonable agreement with experiments, but transitions between different spatial symmetries are often underpredicted. - Open Access
Quantum Monte Carlo calculations of electromagnetic transitions in 8Be with meson-exchange currents derived from chiral effective field theory
We report quantum Monte Carlo calculations of electromagnetic transitions in 8Be. The realistic Argonne v18 two-nucleon and Illinois-7 three-nucleon potentials are used to generate the ground state and nine excited states, with energies that are in excellent agreement with experiment. A dozen M1 and eight E2 transition matrix elements between these states are then evaluated. The E2 matrix elements are computed only in impulse approximation, with those transitions from broad resonant states requiring special treatment. The M1 matrix elements include two-body meson-exchange currents derived from chiral effective field theory, which typically contribute 20--30% of the total expectation value. Many of the transitions are between isospin-mixed states; the calculations are performed for isospin-pure states and then combined with empirical mixing coefficients to compare to experiment. Alternate mixings are also explored. In general, we find that transitions between states that have the same dominant spatial symmetry are in reasonable agreement with experiment, but those transitions between different spatial symmetries are often underpredicted.
Open AccessQuantum Monte Carlo calculations of electromagnetic transitions in 8Be with meson-exchange currents derived from chiral effective field theory
We report quantum Monte Carlo calculations of electromagnetic transitions in 8Be. The realistic Argonne v18 two-nucleon and Illinois-7 three-nucleon potentials are used to generate the ground state and nine excited states, with energies that are in excellent agreement with experiment. A dozen M1 and eight E2 transition matrix elements between these states are then evaluated. The E2 matrix elements are computed only in impulse approximation, with those transitions from broad resonant states requiring special treatment. The M1 matrix elements include two-body meson-exchange currents derived from chiral effective field theory, which typically contribute 20--30% of the total expectation value. Many of the transitions are between isospin-mixed states; the calculations are performed for isospin-pure states and then combined with empirical mixing coefficients to compare to experiment. Alternate mixings are also explored. In general, we find that transitions between states that have the same dominant spatial symmetry are in reasonable agreement with experiment, but those transitions between different spatial symmetries are often underpredicted.
- Top Cited Papers
- 10 February 2014
- Published by American Physical Society (APS) in Physical Review C
- Vol. 89 (2)
Nucleon and nucleon-pair momentum distributions innucleiMomentum distributions of nucleons and pairs of nucleons not only reflect the short-range structure of light nuclei arising from tensor and spin-isospin correlations, they also provide useful insights into electroweak interactions with such nuclei.
- 10 February 2014
- Published by American Physical Society (APS) in Physical Review C
- Vol. 89 (2)
Top Cited PapersNucleon and nucleon-pair momentum distributions innucleiMomentum distributions of nucleons and pairs of nucleons not only reflect the short-range structure of light nuclei arising from tensor and spin-isospin correlations, they also provide useful insights into electroweak interactions with such nuclei.
- Open Access
Nucleon and nucleon-pair momentum distributions in A <= 12 nuclei
We report variational Monte Carlo calculations of single-nucleon momentum distributions for A <= 12 nuclei and nucleon-pair and nucleon-cluster momentum distributions for A <= 8. The wave functions have been generated for a Hamiltonian containing the Argonne v18 two-nucleon and Urbana X three-nucleon potentials. The single-nucleon and nucleon-pair momentum distributions exhibit universal features attributable to the one-pion-exchange tensor interaction. The single-nucleon distributions are broken down into proton and neutron components and spin-up and spin-down components where appropriate. The nucleon-pair momentum distributions are given separately for pp and pn pairs. The nucleon-cluster momentum distributions include dp in 3He, tp and dd in 4He, alpha-d in 6Li, alpha-t in 7Li, and alpha-alpha in 8Be. Detailed tables are provided on-line for download.
Open AccessNucleon and nucleon-pair momentum distributions in A <= 12 nuclei
We report variational Monte Carlo calculations of single-nucleon momentum distributions for A <= 12 nuclei and nucleon-pair and nucleon-cluster momentum distributions for A <= 8. The wave functions have been generated for a Hamiltonian containing the Argonne v18 two-nucleon and Urbana X three-nucleon potentials. The single-nucleon and nucleon-pair momentum distributions exhibit universal features attributable to the one-pion-exchange tensor interaction. The single-nucleon distributions are broken down into proton and neutron components and spin-up and spin-down components where appropriate. The nucleon-pair momentum distributions are given separately for pp and pn pairs. The nucleon-cluster momentum distributions include dp in 3He, tp and dd in 4He, alpha-d in 6Li, alpha-t in 7Li, and alpha-alpha in 8Be. Detailed tables are provided on-line for download.
- 31 October 2013
- Published by American Physical Society (APS) in Physical Review C
- Vol. 88 (4)
Charge-symmetry breaking forces and isospin mixing inBeWe report Green's function Monte Carlo calculations of isospin-mixing (IM) matrix elements for the ${2}^{+}$, ${1}^{+}$, and ${3}^{+}$ $T=0$ and 1 pairs of states at 16\char21{}19 MeV excitation in ${}^{8}$Be. The realistic Argonne ${v}_{18}$ (AV18) two-nucleon and Illinois-7 three-nucleon potentials are used to generate the nuclear wave functions. Contributions from the full electromagnetic interaction and strong class III charge-symmetry breaking (CSB) components of the AV18 potential are evaluated. We also examine two theoretically more complete CSB potentials based on $$\rho${}$-$$\omega${}$ mixing, tuned to give the same neutron-neutron scattering length as AV18. The contribution of these different CSB potentials to the ${}^{3}$H-${}^{3}$He, ${}^{7}$Li-${}^{7}$Be, and ${}^{8}$Li-${}^{8}$B isovector energy differences is evaluated and reasonable agreement with experiment is obtained. Finally, for the ${}^{8}$Be IM calculation we add the small class IV CSB terms coming from one-photon, one-pion, and one-$$\rho${}$ exchange, as well as $$\rho${}$-$$\omega${}$ mixing. The expectation values of the three CSB models vary by up to 20% in the isovector energy differences, but only by 10% or less in the IM matrix element. The total matrix element gives 85\char21{}90% of the experimental IM value of $$-${}145$ keV for the ${2}^{+}$ doublet, with about two thirds coming from the Coulomb interaction. We also report the IM matrix element to the first ${2}^{+}$ state at 3 MeV excitation, which is the final state for various tests of the standard model for $$\beta${}$ decay.- 31 October 2013
- Published by American Physical Society (APS) in Physical Review C
- Vol. 88 (4)
Charge-symmetry breaking forces and isospin mixing inBeWe report Green's function Monte Carlo calculations of isospin-mixing (IM) matrix elements for the ${2}^{+}$, ${1}^{+}$, and ${3}^{+}$ $T=0$ and 1 pairs of states at 16\char21{}19 MeV excitation in ${}^{8}$Be. The realistic Argonne ${v}_{18}$ (AV18) two-nucleon and Illinois-7 three-nucleon potentials are used to generate the nuclear wave functions. Contributions from the full electromagnetic interaction and strong class III charge-symmetry breaking (CSB) components of the AV18 potential are evaluated. We also examine two theoretically more complete CSB potentials based on $$\rho${}$-$$\omega${}$ mixing, tuned to give the same neutron-neutron scattering length as AV18. The contribution of these different CSB potentials to the ${}^{3}$H-${}^{3}$He, ${}^{7}$Li-${}^{7}$Be, and ${}^{8}$Li-${}^{8}$B isovector energy differences is evaluated and reasonable agreement with experiment is obtained. Finally, for the ${}^{8}$Be IM calculation we add the small class IV CSB terms coming from one-photon, one-pion, and one-$$\rho${}$ exchange, as well as $$\rho${}$-$$\omega${}$ mixing. The expectation values of the three CSB models vary by up to 20% in the isovector energy differences, but only by 10% or less in the IM matrix element. The total matrix element gives 85\char21{}90% of the experimental IM value of $$-${}145$ keV for the ${2}^{+}$ doublet, with about two thirds coming from the Coulomb interaction. We also report the IM matrix element to the first ${2}^{+}$ state at 3 MeV excitation, which is the final state for various tests of the standard model for $$\beta${}$ decay.- Open Access
Charge-symmetry breaking forces and isospin mixing in 8Be
We report Green's function Monte Carlo calculations of isospin-mixing (IM) matrix elements for the 2+, 1+, and 3+ T=0,1 pairs of states at 16--19 MeV excitation in 8Be. The realistic Argonne v18 (AV18) two-nucleon and Illinois-7 three-nucleon potentials are used to generate the nuclear wave functions. Contributions from the full electromagnetic interaction and strong class III charge-symmetry-breaking (CSB) components of the AV18 potential are evaluated. We also examine two theoretically more complete CSB potentials based on rho-omega mixing, tuned to give the same neutron-neutron scattering length as AV18. The contribution of these different CSB potentials to the 3H-3He, 7Li-7Be, and 8Li-8B isovector energy differences is evaluated and reasonable agreement with experiment is obtained. Finally, for the 8Be IM calculation we add the small class IV CSB terms coming from one-photon, one-pion, and one-rho exchange, as well as rho-omega mixing. The expectation values of the three CSB models vary by up to 20% in the isovector energy differences, but only by 10% or less in the IM matrix element. The total matrix element gives 85--90% of the experimental IM value of -145 keV for the 2+ doublet, with about two thirds coming from the Coulomb interaction. We also report the IM matrix element to the first 2+ state at 3 MeV excitation, which is the final state for various tests of the Standard Model for beta-decay.
Open AccessCharge-symmetry breaking forces and isospin mixing in 8Be
We report Green's function Monte Carlo calculations of isospin-mixing (IM) matrix elements for the 2+, 1+, and 3+ T=0,1 pairs of states at 16--19 MeV excitation in 8Be. The realistic Argonne v18 (AV18) two-nucleon and Illinois-7 three-nucleon potentials are used to generate the nuclear wave functions. Contributions from the full electromagnetic interaction and strong class III charge-symmetry-breaking (CSB) components of the AV18 potential are evaluated. We also examine two theoretically more complete CSB potentials based on rho-omega mixing, tuned to give the same neutron-neutron scattering length as AV18. The contribution of these different CSB potentials to the 3H-3He, 7Li-7Be, and 8Li-8B isovector energy differences is evaluated and reasonable agreement with experiment is obtained. Finally, for the 8Be IM calculation we add the small class IV CSB terms coming from one-photon, one-pion, and one-rho exchange, as well as rho-omega mixing. The expectation values of the three CSB models vary by up to 20% in the isovector energy differences, but only by 10% or less in the IM matrix element. The total matrix element gives 85--90% of the experimental IM value of -145 keV for the 2+ doublet, with about two thirds coming from the Coulomb interaction. We also report the IM matrix element to the first 2+ state at 3 MeV excitation, which is the final state for various tests of the Standard Model for beta-decay.
- Open Access
- 24 July 2013
- Published by Sissa Medialab Srl
- Vol. 172, 105
GFMC calculations of electromagnetic moments and M1 transitions in A ≤ 9 nuclei
We present recent Green's function Monte Carlo calculations of magnetic moments and M1 transitions in A ≤ 9 nuclei, which include corrections arising from two-body meson-exchange electromagnetic currents. Two-body effects provide significant corrections to the calculated observables, bringing them in excellent agreement with the experimental data. In particular, we find that twobody corrections are especially large in the A = 9, T = 3/2 systems, in which they account for up to ∼ 20% (∼ 40%) of the total predicted value for the 9 Li (9 C) magnetic moment.
- 24 July 2013
- Published by Sissa Medialab Srl
- Vol. 172, 105
Open AccessGFMC calculations of electromagnetic moments and M1 transitions in A ≤ 9 nuclei
We present recent Green's function Monte Carlo calculations of magnetic moments and M1 transitions in A ≤ 9 nuclei, which include corrections arising from two-body meson-exchange electromagnetic currents. Two-body effects provide significant corrections to the calculated observables, bringing them in excellent agreement with the experimental data. In particular, we find that twobody corrections are especially large in the A = 9, T = 3/2 systems, in which they account for up to ∼ 20% (∼ 40%) of the total predicted value for the 9 Li (9 C) magnetic moment.
- 25 March 2013
- Published by American Physical Society (APS) in Physical Review C
- Vol. 87 (3)
Quantum Monte Carlo calculations of electromagnetic moments and transitions innuclei with meson-exchange currents derived from chiral effective field theoryQuantum Monte Carlo calculations of electromagnetic moments and transitions are reported for $A$\le${}9$ nuclei. The realistic Argonne ${v}_{18}$ two-nucleon and Illinois-7 three-nucleon potentials are used to generate the nuclear wave functions. Contributions of two-body meson-exchange current (MEC) operators are included for magnetic moments and $M1$ transitions. The MEC operators have been derived in both a standard nuclear physics approach and a chiral effective field theory formulation with pions and nucleons including up to one-loop corrections. The two-body MEC contributions provide significant corrections and lead to very good agreement with experiment. Their effect is particularly pronounced in the $A=9$, $T=3/2$ systems, in which they provide up to $$\sim${}20%$ ($$\sim${}40%$) of the total predicted value for the ${}^{9}$Li (${}^{9}$C) magnetic moment.- 25 March 2013
- Published by American Physical Society (APS) in Physical Review C
- Vol. 87 (3)
Quantum Monte Carlo calculations of electromagnetic moments and transitions innuclei with meson-exchange currents derived from chiral effective field theoryQuantum Monte Carlo calculations of electromagnetic moments and transitions are reported for $A$\le${}9$ nuclei. The realistic Argonne ${v}_{18}$ two-nucleon and Illinois-7 three-nucleon potentials are used to generate the nuclear wave functions. Contributions of two-body meson-exchange current (MEC) operators are included for magnetic moments and $M1$ transitions. The MEC operators have been derived in both a standard nuclear physics approach and a chiral effective field theory formulation with pions and nucleons including up to one-loop corrections. The two-body MEC contributions provide significant corrections and lead to very good agreement with experiment. Their effect is particularly pronounced in the $A=9$, $T=3/2$ systems, in which they provide up to $$\sim${}20%$ ($$\sim${}40%$) of the total predicted value for the ${}^{9}$Li (${}^{9}$C) magnetic moment.- Open Access
Quantum Monte Carlo calculations of electromagnetic moments and transitions in A <= 9 nuclei with meson-exchange currents derived from chiral effective field theory
Quantum Monte Carlo calculations of electromagnetic moments and transitions are reported for A <= 9 nuclei. The realistic Argonne v18 two-nucleon and Illinois-7 three-nucleon potentials are used to generate the nuclear wave functions. Contributions of two-body meson-exchange current (MEC) operators are included for magnetic moments and M1 transitions. The MEC operators have been derived in both a standard nuclear physics approach and a chiral effective field theory formulation with pions and nucleons including up to one-loop corrections. The two-body MEC contributions provide significant corrections and lead to very good agreement with experiment. Their effect is particularly pronounced in the A=9, T=3/2 systems, in which they provide up to 20% (40 %) of the total predicted value for the 9Li (9C) magnetic moment.
Open AccessQuantum Monte Carlo calculations of electromagnetic moments and transitions in A <= 9 nuclei with meson-exchange currents derived from chiral effective field theory
Quantum Monte Carlo calculations of electromagnetic moments and transitions are reported for A <= 9 nuclei. The realistic Argonne v18 two-nucleon and Illinois-7 three-nucleon potentials are used to generate the nuclear wave functions. Contributions of two-body meson-exchange current (MEC) operators are included for magnetic moments and M1 transitions. The MEC operators have been derived in both a standard nuclear physics approach and a chiral effective field theory formulation with pions and nucleons including up to one-loop corrections. The two-body MEC contributions provide significant corrections and lead to very good agreement with experiment. Their effect is particularly pronounced in the A=9, T=3/2 systems, in which they provide up to 20% (40 %) of the total predicted value for the 9Li (9C) magnetic moment.