A5086558518- Nuclear physics research studies
- Quantum Chromodynamics and Particle Interactions
- Atomic and Molecular Physics
- Advanced NMR Techniques and Applications
- Advanced Chemical Physics Studies
- Quantum, superfluid, helium dynamics
- Particle physics theoretical and experimental studies
- Astronomical and nuclear sciences
- Nuclear Physics and Applications
- High-Energy Particle Collisions Research
- Physics of Superconductivity and Magnetism
- Nuclear reactor physics and engineering
- Superconducting Materials and Applications
- Theoretical and Computational Physics
- Quantum chaos and dynamical systems
- Atomic and Subatomic Physics Research
- Scientific Research and Discoveries
- Cold Atom Physics and Bose-Einstein Condensates
- Statistical Mechanics and Entropy
- High-pressure geophysics and materials
- advanced mathematical theories
- Complex Systems and Time Series Analysis
- Fluid Dynamics and Turbulent Flows
- Gas Dynamics and Kinetic Theory
- Surface and Thin Film Phenomena
Michigan State University
2015-2025
Facility for Rare Isotope Beams
2025
National Superconducting Cyclotron Laboratory
2009-2018
Astronomy and Space
2008-2014
The Ohio State University
2005-2008
University of Washington
2003-2004
Stony Brook University
2001-2003
State University of New York
2003
University of Naples Federico II
2002
We present nuclear matter calculations based on low-momentum interactions derived from chiral effective field theory potentials. The current use an improved treatment of the three-nucleon force (3NF) contribution that includes a corrected combinatorial factor beyond Hartree-Fock was omitted in previous calculations. find realistic saturation properties using parameters fit only to few-body data, but with larger uncertainty estimates cutoff dependence and 3NF parametrization than
The similarity renormalization group (SRG) is based on unitary transformations that suppress off-diagonal matrix elements, forcing the Hamiltonian toward a band-diagonal form. A simple SRG transformation applied to nucleon-nucleon interactions leads greatly improved convergence properties while preserving observables and provides method consistently evolve many-body potentials other operators.
We present a nucleus-dependent valence-space approach for calculating ground and excited states of nuclei, which generalizes the shell-model in-medium similarity renormalization group to an ensemble reference with fractionally filled orbitals. Because is used only as reference, not represent physical states, no symmetry restoration required. This allows us capture 3N forces among valence nucleons Hamiltonian specifically targeted each nucleus interest. Predicted ground-state energies from...
We present the first ab initio construction of valence-space Hamiltonians for medium-mass nuclei based on chiral two- and three-nucleon interactions using in-medium similarity renormalization group. When applied to oxygen isotopes, we find experimental ground-state energies are well reproduced, including flat trend beyond drip line at (24)O. Similarly, natural-parity spectra in (21,22,23,24)O agreement with experiment, predictions excited states (25,26)O. The results exhibit a weak...
We present a new ab initio method that uses similarity renormalization group (SRG) techniques to continuously diagonalize nuclear many-body Hamiltonians. In contrast with applications of the SRG two- and three-nucleon interactions in free space, we perform evolution "in medium" directly A-body system interest. The in-medium approach has advantage one can approximately evolve 3,…,A-body operators using only two-body machinery based on normal-ordering techniques. is nonperturbative be tailored...
A low momentum nucleon-nucleon (NN) potential V-low-k is derived from meson exhange potentials by integrating out the model dependent high modes of V_NN. The smooth and approximately unique used as input for shell calculations instead usual Brueckner G matrix. Such an approach eliminates nuclear mass dependence interaction one finds in matrix approach, allowing same to be different regions. Shell 18O, 134Te 135I using have been performed. For cut-off Lambda vicinity 2 fm-1, our calculated...
We use the recently proposed in-medium similarity renormalization group (IM-SRG) to carry out a systematic study of closed-shell nuclei up ${}^{56}\mathrm{Ni}$, based on chiral two- plus three-nucleon interactions. analyze capabilities IM-SRG by comparing our results for ground-state energy coupled cluster calculations, as well quasiexact from importance-truncated no-core shell model. Using Hamiltonians whose resolution scales are lowered free-space SRG evolution, we obtain good agreement...
We present a nonperturbative derivation of effective valence-shell Hamiltonians in the framework recently developed in-medium similarity renormalization group (IM-SRG). As first application, we calculate spectra $p$- and $sd$-shell nuclei, $^6$Li $^{18}$O, based on evolved chiral nucleon-nucleon interactions. For $^6$Li, spectrum is very good agreement with ab-initio results. IM-SRG provides new method for shell model to systematically go beyond interaction techniques diagrammatic expansions.
We use the newly developed multireference in-medium similarity renormalization group to study all even isotopes of calcium and nickel isotopic chains, based on two- plus three-nucleon interactions derived from chiral effective field theory. present results for ground-state two-neutron separation energies quantify their theoretical uncertainties. At shell closures, we find excellent agreement with coupled-cluster obtained same Hamiltonians. Our confirm importance $3N$ obtain a correct...
We present an improved variant of the in-medium similarity renormalization group (IM-SRG) based on Magnus expansion. In new formulation, one solves flow equations for anti-hermitian operator that, upon exponentiation, yields unitary transformation IM-SRG. The resulting can be solved using a first-order Euler method without any loss accuracy, in substantial memory savings and modest computational speedups. Since obtains directly, additional operators beyond Hamiltonian accomplished with...
We present ab initio predictions for ground and excited states of doubly open-shell fluorine neon isotopes based on chiral two- three-nucleon interactions. use the in-medium similarity renormalization group to derive mass-dependent $sd$ valence-space Hamiltonians. The experimental ground-state energies are reproduced through neutron number $N=14$, beyond which a new targeted normal-ordering procedure improves agreement with data large-space multireference calculations. For spectroscopy, we...
The effective low-momentum interaction Vlowk is applied to three- and four-nucleon systems. We investigate the 3H, 3He 4He binding energies for a wide range of momentum cutoffs. By construction, all low-energy two-body observables are cutoff-independent, therefore, any cutoff dependence due missing three-body or higher-body forces. argue that reasonable cutoffs similar high-order interactions derived from chiral field theory. This motivates augmenting by corresponding three-nucleon set...
We present the formalism for consistently transforming transition operators within in-medium similarity renormalization group framework. implement operator transformation in both equations-of-motion and valence-space variants, first results electromagnetic transitions moments medium-mass nuclei using consistently-evolved operators, including induced two-body parts. These are compared to experimental values, and--where possible--the of no-core shell model calculations same input chiral...
The nuclear shell model has been perhaps the most important conceptual and computational paradigm for understanding of structure atomic nuclei. While predominantly used in a phenomenological context, there have efforts stretching back over half century to derive parameters based on realistic interaction between nucleons. More recently, several ab initio many-body methods---in particular perturbation theory, no-core model, in-medium similarity renormalization group, coupled cluster...
In a recent series of articles, Gebremariam, Bogner, and Duguet derived microscopically based nuclear energy density functional by applying the matrix expansion (DME) to Hartree-Fock obtained from chiral effective field theory two- three-nucleon interactions. Owing structure interactions, each coupling in DME is given as sum constant arising zero-range contact interactions function finite-range pion exchanges. Because contributions have essentially same those entering empirical Skyrme...
Recent experiments have succeeded in isolating processes for which short-range correlation (SRC) physics is dominant and well accounted by SRC phenomenology. But an alternative compelling picture emerges from renormalization group (RG) evolution to low RG resolution. At high resolution, SRCs are identified as components the nuclear wave function with relative pair momenta greater than Fermi momentum. Scale separation results wave-function factorization that can be exploited phenomenologies...
Similarity renormalization group (SRG) flow equations can be used to unitarily soften nuclear Hamiltonians by decoupling high-energy intermediate-state contributions low-energy observables while maintaining the natural hierarchy of many-body forces. Analogous consistently evolve operators so that are unchanged if no approximations made. The question in practice is whether advantages a softer Hamiltonian and less-correlated wave functions might offset complications approximating applying...