A5021251956- Nuclear physics research studies
- Advanced Chemical Physics Studies
- Atomic and Molecular Physics
- Quantum optics and atomic interactions
- Quantum Chromodynamics and Particle Interactions
- Astronomical and nuclear sciences
- Metamaterials and Metasurfaces Applications
- Spectroscopy and Laser Applications
- Quantum chaos and dynamical systems
- Cold Atom Physics and Bose-Einstein Condensates
- Complex Systems and Time Series Analysis
- Electromagnetic Simulation and Numerical Methods
- High-pressure geophysics and materials
- Physics of Superconductivity and Magnetism
- Quantum, superfluid, helium dynamics
- Electromagnetic Scattering and Analysis
- Semiconductor Quantum Structures and Devices
- Quantum and electron transport phenomena
- Reservoir Engineering and Simulation Methods
- Scientific Research and Discoveries
- Advanced Numerical Methods in Computational Mathematics
- Advanced NMR Techniques and Applications
- Atomic and Subatomic Physics Research
Riverside Research Institute
2023
Michigan State University
2015-2018
The Ohio State University
2017-2018
National Superconducting Cyclotron Laboratory
2015-2017
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 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...
We present two new methods for performing ab initio calculations of excited states closed-shell systems within the in-medium similarity renormalization group (IMSRG) framework. Both are based on combining IMSRG with simple many-body commonly used to target states, such as Tamm-Dancoff approximation (TDA) and equations-of-motion (EOM) techniques. In first approach, a two-step sequential transformation is drive Hamiltonian form where TDA calculation (i.e., diagonalization in space...
Efforts to describe nuclear structure and dynamics from first principles have advanced significantly in recent years. Exact methods for light nuclei are now able include continuum degrees of freedom treat reactions on the same footing, multiple approximate, computationally efficient many-body been developed that can be routinely applied medium-mass nuclei. This has made it possible confront modern interactions Chiral Effective Field Theory, rooted Quantum Chromodynamics with a wealth...
We present and compare several many-body methods as applied to two-dimensional quantum dots with circular symmetry. calculate the approximate ground state energy using a harmonic oscillator basis optimized by Hartree-Fock (HF) theory further improve two post-HF methods: in-medium similarity renormalization group coupled cluster singles doubles. With application of quasidegenerate perturbation or equations-of-motion method results previous methods, we obtain addition removal energies well....
A recompressed nested cross approximation (rNCA) based closely on the recent fast (fNCA) algorithm is formulated in this article. The proposed method builds previous work which fNCA was a purely algebraic and kernel-independent fashion, using top-down recursive application of adaptive cross-approximation (ACA). Our employs ACA recompression to avoid need compute low-rank approximations excessively large far-field matrices, thus mitigates effects high-frequency rank growth run-time scaling...